|**LOANS AND ALLOWANCE FOR CREDIT LOSSES (Loan and Lease Portfolio Composition) (Details) - USD ($) $ in Thousands**                                                                                                                                                                                                                                                                                                                                                                                      | Mar. 31, 2017                                                                                                                                                                                                                                                                                                                | Dec. 31, 2016                                                                                                                                                        | Mar. 31, 2016
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------
|**Loans Receivable [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                      |              
|Total loans held for investment                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | [1],[2]                                                                                                                                                                                                                                                                                                                      | $ 83,714,900                                                                                                                                                         | $ 85,819,785 
|Loans held for investment with fixed rate of interest                                                                                                                                                                                                                                                                                                                                                                                                                                                    |                                                                                                                                                                                                                                                                                                                              | 50,822,537                                                                                                                                                           | 51,752,761   
|Loans held for investment with variable rate of interest                                                                                                                                                                                                                                                                                                                                                                                                                                                 |                                                                                                                                                                                                                                                                                                                              | $ 32,892,363                                                                                                                                                         | $ 34,067,024 
|Loans held for investment, percent of total loans                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                              | 100.00%                                                                                                                                                              | 100.00%      
|Loans held for investment with fixed rate of interest, percent of total loans                                                                                                                                                                                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                              | 60.70%                                                                                                                                                               | 60.30%       
|Loans held for investment with variable rate of interest, percent of total loans                                                                                                                                                                                                                                                                                                                                                                                                                         |                                                                                                                                                                                                                                                                                                                              | 39.30%                                                                                                                                                               | 39.70%       
|Net increase in loan balances                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                              | $ 968,300                                                                                                                                                            | $ 845,800    
|Ending balance, collectively evaluated for impairment                                                                                                                                                                                                                                                                                                                                                                                                                                                    |                                                                                                                                                                                                                                                                                                                              | 76,990,063                                                                                                                                                           |              
|Commercial                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                      |              
|**Loans Receivable [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                      |              
|Total loans held for investment                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                                                              | $ 42,311,972                                                                                                                                                         | $ 44,440,128 
|Loans held for investment, percent of total loans                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                              | 50.50%                                                                                                                                                               | 51.80%       
|Ending balance, collectively evaluated for impairment                                                                                                                                                                                                                                                                                                                                                                                                                                                    |                                                                                                                                                                                                                                                                                                                              | $ 41,636,856                                                                                                                                                         |              
|Commercial | Commercial real estate loans                                                                                                                                                                                                                                                                                                                                                                                                                                                                |                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                      |              
|**Loans Receivable [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                      |              
|Total loans held for investment                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                                                              | $ 9,883,926                                                                                                                                                          | $ 10,112,043 
|Loans held for investment, percent of total loans                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                              | 11.80%                                                                                                                                                               | 11.80%       
|Commercial | Commercial and industrial loans                                                                                                                                                                                                                                                                                                                                                                                                                                                             |                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                      |              
|**Loans Receivable [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                      |              
|Total loans held for investment                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                                                              | $ 17,218,865                                                                                                                                                         | $ 18,812,002 
|Loans held for investment, percent of total loans                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                              | 20.60%                                                                                                                                                               | 21.90%       
|Commercial | Multifamily loans                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                      |              
|**Loans Receivable [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                      |              
|Total loans held for investment                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                                                              | $ 8,462,464                                                                                                                                                          | $ 8,683,680  
|Loans held for investment, percent of total loans                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                              | 10.10%                                                                                                                                                               | 10.10%       
|Commercial | Other commercial                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                      |              
|**Loans Receivable [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                      |              
|Total loans held for investment                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                                                              | $ 6,746,717                                                                                                                                                          | $ 6,832,403  
|Loans held for investment, percent of total loans                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                              | 8.00%                                                                                                                                                                | 8.00%        
|Consumer                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                      |              
|**Loans Receivable [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                      |              
|Total loans held for investment                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                                                              | $ 41,402,928                                                                                                                                                         | $ 41,379,657 
|Loans held for investment, percent of total loans                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                              | 49.50%                                                                                                                                                               | 48.20%       
|Ending balance, collectively evaluated for impairment                                                                                                                                                                                                                                                                                                                                                                                                                                                    |                                                                                                                                                                                                                                                                                                                              | $ 35,353,207                                                                                                                                                         |              
|Consumer | RICs and auto loans - originated                                                                                                                                                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                      |              
|**Loans Receivable [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                      |              
|Total loans held for investment                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                                                              | 22,729,892                                                                                                                                                           | $ 22,104,918 
|Consumer loans secured by real estate                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                      |              
|**Loans Receivable [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                      |              
|Total loans held for investment                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                                                              | $ 13,742,515                                                                                                                                                         | $ 13,776,464 
|Loans held for investment, percent of total loans                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                              | 16.40%                                                                                                                                                               | 16.10%       
|Consumer loans secured by real estate | Residential mortgages                                                                                                                                                                                                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                      |              
|**Loans Receivable [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                      |              
|Total loans held for investment                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                                                              | $ 7,801,175                                                                                                                                                          | $ 7,775,272  
|Loans held for investment, percent of total loans                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                              | 9.30%                                                                                                                                                                | 9.10%        
|Consumer loans secured by real estate | Home equity loans and lines of credit                                                                                                                                                                                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                      |              
|**Loans Receivable [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                      |              
|Total loans held for investment                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                                                              | $ 5,941,340                                                                                                                                                          | $ 6,001,192  
|Loans held for investment, percent of total loans                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                              | 7.10%                                                                                                                                                                | 7.00%        
|Consumer loans not secured by real estate | RICs and auto loans - originated                                                                                                                                                                                                                                                                                                                                                                                                                             |                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                      |              
|**Loans Receivable [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                      |              
|Total loans held for investment                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                                                              | $ 22,729,892                                                                                                                                                         | $ 22,104,918 
|Loans held for investment, percent of total loans                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                              | 27.20%                                                                                                                                                               | 25.80%       
|Consumer loans not secured by real estate | RICs and auto loans - purchased                                                                                                                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                      |              
|**Loans Receivable [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                      |              
|Total loans held for investment                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                                                              | $ 2,976,567                                                                                                                                                          | $ 3,468,803  
|Loans held for investment, percent of total loans                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                              | 3.60%                                                                                                                                                                | 4.00%        
|Consumer loans not secured by real estate | Personal unsecured loans                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                      |              
|**Loans Receivable [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                      |              
|Total loans held for investment                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                                                              | $ 1,211,922                                                                                                                                                          | $ 1,234,094  
|Loans held for investment, percent of total loans                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                              | 1.40%                                                                                                                                                                | 1.40%        
|Consumer loans not secured by real estate | Other consumer                                                                                                                                                                                                                                                                                                                                                                                                                                               |                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                      |              
|**Loans Receivable [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                      |              
|Total loans held for investment                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                                                              | $ 742,032                                                                                                                                                            | $ 795,378    
|Loans held for investment, percent of total loans                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                              | 0.90%                                                                                                                                                                | 0.90%        
|Unallocated                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                      |              
|**Loans Receivable [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                      |              
|Ending balance, collectively evaluated for impairment                                                                                                                                                                                                                                                                                                                                                                                                                                                    |                                                                                                                                                                                                                                                                                                                              | $ 0                                                                                                                                                                  |              
|Unallocated | Other commercial                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                      |              
|**Loans Receivable [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                      |              
|Ending balance, collectively evaluated for impairment                                                                                                                                                                                                                                                                                                                                                                                                                                                    |                                                                                                                                                                                                                                                                                                                              | $ 3,600,000                                                                                                                                                          | $ 3,700,000  
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        
|[1]
Loans held-for-investment ("LHFI") includes $202.5 million and $217.2 million of loans recorded at fair value at March 31, 2017 and December 31, 2016, respectively.[2]
The Company has interests in certain securitization trusts ("Trusts") that are considered variable interest entities ("VIEs") for accounting purposes. The Company consolidates VIEs where it is deemed the primary beneficiary. See Note 6 to these Condensed Consolidated Financial Statements for additional information. | [1]                                                                                                                                                                                                                                                                                                                          | Loans held-for-investment ("LHFI") includes $202.5 million and $217.2 million of loans recorded at fair value at March 31, 2017 and December 31, 2016, respectively. | [2]          
|[1]                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | Loans held-for-investment ("LHFI") includes $202.5 million and $217.2 million of loans recorded at fair value at March 31, 2017 and December 31, 2016, respectively.                                                                                                                                                        
|[2]                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | The Company has interests in certain securitization trusts ("Trusts") that are considered variable interest entities ("VIEs") for accounting purposes. The Company consolidates VIEs where it is deemed the primary beneficiary. See Note 6 to these Condensed Consolidated Financial Statements for additional information.

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