|**Accumulated Other Comprehensive Income (Loss) (Tables)**            | 3 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
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|**Equity [Abstract]**                                                 |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              
|Schedule of accumulated other comprehensive income (loss)             | The following table summarizes the changes in the balances of each component of accumulated other comprehensive income (loss), net of tax, as ofMarch 31, 2016and2015:Accumulated Other Comprehensive Income (Loss)Unrealized Gains (Losses) on Securities Available for SaleUnrealized Gains (Losses) on Cash Flow HedgesUnrealized Gains (Losses) on Defined Benefit PlansTotalBalance at December 31, 2015$12,325$(2,347)$(11,340)$(1,362)Other comprehensive income before reclassifications5,135(1,270)3,865Amounts reclassified from accumulated other comprehensive income(648)211(437)Period change4,487(1,059)—3,428Balance at March 31, 2016$16,812$(3,406)$(11,340)$2,066Balance at December 31, 2014$14,098$(2,182)$(13,546)$(1,630)Other comprehensive income before reclassifications980(829)151Amounts reclassified from accumulated other comprehensive income(666)230(436)Period change314(599)—(285)Balance at March 31, 2015$14,412$(2,781)$(13,546)$(1,915)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              
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|                                                                      | Accumulated Other Comprehensive Income (Loss)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|                                                                      | Unrealized Gains (Losses) on Securities Available for Sale                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   
|Balance at December 31, 2015                                          | $                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
|Other comprehensive income before reclassifications                   | 5,135                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        
|Amounts reclassified from accumulated other comprehensive income      | (648                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         
|Period change                                                         | 4,487                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        
|Balance at March 31, 2016                                             | $                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
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|Balance at December 31, 2014                                          | $                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
|Other comprehensive income before reclassifications                   | 980                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          
|Amounts reclassified from accumulated other comprehensive income      | (666                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         
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|Balance at March 31, 2015                                             | $                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
|Reclassification out of accumulated other comprehensive income (loss) | The following table presents the reclassification adjustments out of accumulated other comprehensive income (loss) that were included in net income in the Consolidated Condensed Statements of Income for thethree months ended March 31, 2016and2015:Amount Reclassified from Accumulated Other Comprehensive Income (Loss) For the Three Months Ended March 31,Details about Accumulated Other Comprehensive Income (Loss)Components20162015Affected Line Item in the Statements of IncomeUnrealized gains (losses) on available for sale securities(1)Realized securities gains (losses) reclassified into income$997$1,025Other income - net realized gains on sales of available for sale securitiesRelated income tax expense(349)(359)Income tax expense$648$666Unrealized gains (losses) on cash flow hedges(2)Interest rate contracts$(324)$(354)Interest expense - subordinated debentures and term loansRelated income tax benefit113124Income tax expense$(211)$(230)Total reclassifications for the period, net of tax$437$436(1)For additional detail related to unrealized gains (losses) on available for sale securities and related amounts reclassified from accumulated        other comprehensive income see NOTE 3. INVESTMENT SECURITIES.(2)For additional detail related to unrealized gains (losses) on cash flow hedges and related amounts reclassified from accumulated other comprehensive income see NOTE 8. DERIVATIVE FINANCIAL INSTRUMENTS.
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|Details about Accumulated Other Comprehensive Income (Loss)Components |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              
|Unrealized gains (losses) on available for sale securities(1)         |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              
|Realized securities gains (losses) reclassified into income           |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              
|Related income tax expense                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              
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|Unrealized gains (losses) on cash flow hedges(2)                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              
|Interest rate contracts                                               |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              
|Related income tax benefit                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              
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|Total reclassifications for the period, net of tax                    |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              
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