Recent Accounting Pronouncements (Details) - USD ($) $ in Thousands			3 Months Ended		9 Months Ended
	Sep. 30, 2018	Jan. 01, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Noninterest Expense			$ 96,477	$ 97,190	$ 305,475	$ 313,583
Non-cash transfer of equity securities previously classified as trading securities and securities available-for-sale					29,000
Reclassification of tax effects from AOCI to retained earnings		$ 6,800
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated sale-leaseback deferred gain, net of tax	50
Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Noninterest Expense			4,200		11,900
Difference between Revenue Guidance in Effect before and after Topic 606 | Card-based | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Noninterest Expense			1,900		5,500
Difference between Revenue Guidance in Effect before and after Topic 606 | Merchant servicing | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Noninterest Expense			$ 2,300		$ 6,400