| **DEPOSITS AND OTHER CUSTOMER ACCOUNTS (Maturities of Certificates of Deposit) (Details) - USD ($) $ in Thousands** | Dec. 31, 2015 | Dec. 31, 2014 |
|---------------------------------------------------------------------------------------------------------------------|---------------|---------------|
| **Financial Instruments Owned and Pledged as Collateral [Line Items]**                                              |          |          |
| Time Deposits, $250,000 or More                                                                                     | $ 1,500,000   | $ 993,400     |
| Securities pledged as collateral, fair value                                                                        | 3,500,000     | 3,500,000     |
| Deposit Liabilities Reclassified as Loans Receivable                                                                | 25,200        | 51,300        |
| **Contractual Maturities, Time Deposits, $100,000 or More [Abstract]**                                              |          |          |
| Three months or less                                                                                                | 1,403,554     |          |
| Over three through six months                                                                                       | 563,199       |          |
| Over six through twelve months                                                                                      | 250,823       |          |
| Over twelve months                                                                                                  | 453,953       |          |
| Total                                                                                                               | 2,671,529     |          |
| **Time Deposits Maturities, after Next Twelve Months [Abstract]**                                                   |          |          |
| 2016                                                                                                                | 7,002,884     |          |
| 2017                                                                                                                | 875,679       |          |
| 2018                                                                                                                | 378,881       |          |
| 2019                                                                                                                | 29,265        |          |
| 2020                                                                                                                | 223,074       |          |
| Thereafter                                                                                                          | 3,220         |          |
| Total                                                                                                               | 8,513,003     | 7,311,309     |
| Public fund deposits                                                                                                |          |          |
| **Financial Instruments Owned and Pledged as Collateral [Line Items]**                                              |          |          |
| Securities pledged as collateral, fair value                                                                        | $ 2,900,000   | $ 2,600,000   |

| X                                                                                                                                                                                                                                            |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Time Deposits, $250,000 or More
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The amount of contractual maturities of domestic and foreign time deposits (including certificates of deposits, individual retirement accounts and open accounts) in denominations of $100,000 or more, after twelve months from the balance sheet date.
+ References
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|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The amount of contractual maturities of domestic and foreign time deposits (including certificates of deposits, individual retirement accounts and open accounts) in denominations of $100,000 or more, for the period from six months through twelve months after the balance sheet date.
+ References
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|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The amount of contractual maturities of domestic and foreign time deposits (including certificates of deposits, individual retirement accounts and open accounts) in denominations of $100,000 or more, for three months or less from the balance sheet date.
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| - Definition
The amount of contractual maturities of domestic and foreign time deposits (including certificates of deposits, individual retirement accounts and open accounts) in denominations of $100,000 or more, for the period from three months through six months after the balance sheet date.
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| - Definition
Amount of deposits held by the entity that have been reclassified as loan balances receivable, for example, but not limited to, overdrafts receivable.
+ References
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| - Definition
Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.
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No definition available.
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|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Fair value of financial instrument held by the entity for its own account (proprietary securities) for trading or investment purposes that are carried at fair value and pledged to counterparties as collateral for financing transactions.
+ References
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|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of time deposits maturing after the fifth fiscal year following the latest fiscal year. Time deposits include, but are not limited to, certificates of deposits. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.
+ References
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|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of time deposits maturing in the fifth fiscal year following the latest fiscal year. Time deposits include, but are not limited to, certificates of deposits. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.
+ References
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| - Definition
Amount of time deposits maturing in the fourth fiscal year following the latest fiscal year. Time deposits include, but are not limited to, certificates of deposits. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.
+ References
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|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of time deposits maturing in the next fiscal year following the latest fiscal year. Time deposits include, but are not limited to, certificates of deposits. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.
+ References
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|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of time deposits maturing in the third fiscal year following the latest fiscal year. Time deposits include, but are not limited to, certificates of deposits. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.
+ References
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| - Definition
Amount of time deposits maturing in the second fiscal year following the latest fiscal year. Time deposits include, but are not limited to, certificates of deposits. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.
+ References
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|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of deposits that cannot be withdrawn before a set date without penalty or for which notice of withdrawal is required. Time deposits include, but are not limited to, certificates of deposits, individual retirement accounts and open accounts.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The aggregate amount of domestic and foreign time deposit liabilities (including certificates of deposits, individual retirement accounts and open accounts) in denominations of $100,000 or more.
+ References
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