|**Deposits (Tables)**                                    | 12 Months Ended                                                                                                                                                                                                                                                                                                                                                                                 
|-------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
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|**Banking and Thrift [Abstract]**                        |                                                                                                                                                                                                                                                                                                                                                                                                 
|Schedule of Deposits                                     | The composition of the deposit portfolio is included in the table below for the years indicated:December 31, 2016December 31, 2015Demand deposits$2,866,853$2,576,283Savings deposits1,560,7521,518,722Certificates and other time deposits of $100,000 or more276,274323,698Other certificates and time deposits471,247556,476Brokered deposits381,372314,468Total deposits$5,556,498$5,289,647
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|                                                         |                                                                                                                                                                                                                                                                                                                                                                                                 
|                                                         | December 31, 2016                                                                                                                                                                                                                                                                                                                                                                               
|Demand deposits                                          | $                                                                                                                                                                                                                                                                                                                                                                                               
|Savings deposits                                         | 1,560,752                                                                                                                                                                                                                                                                                                                                                                                       
|Certificates and other time deposits of $100,000 or more | 276,274                                                                                                                                                                                                                                                                                                                                                                                         
|Other certificates and time deposits                     | 471,247                                                                                                                                                                                                                                                                                                                                                                                         
|Brokered deposits                                        | 381,372                                                                                                                                                                                                                                                                                                                                                                                         
|Total deposits                                           | $                                                                                                                                                                                                                                                                                                                                                                                               
|Summary of Contractual Maturities of Time Deposits       | At December 31, 2016, the contractual maturities of time deposits are summarized as follows:Certificates and Other Time Deposits2017$621,2052018230,5602019137,090202065,396202143,010After 202131,632$1,128,893                                                                                                                                                                                
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|                                                         |                                                                                                                                                                                                                                                                                                                                                                                                 
|                                                         | Certificates and Other Time Deposits                                                                                                                                                                                                                                                                                                                                                            
|2017                                                     | $                                                                                                                                                                                                                                                                                                                                                                                               
|2018                                                     | 230,560                                                                                                                                                                                                                                                                                                                                                                                         
|2019                                                     | 137,090                                                                                                                                                                                                                                                                                                                                                                                         
|2020                                                     | 65,396                                                                                                                                                                                                                                                                                                                                                                                          
|2021                                                     | 43,010                                                                                                                                                                                                                                                                                                                                                                                          
|After 2021                                               | 31,632                                                                                                                                                                                                                                                                                                                                                                                          
|                                                         | $                                                                                                                                                                                                                                                                                                                                                                                               

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