Revenue from Contracts with Customers Reclassification of Bank Card Transaction Fees (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Reclassification of Bank Card Transaction Fees [Line Items]
Bank card transaction fees	$ 43,215	$ 37,295	$ 84,668	$ 73,046
Non-interest income	124,850	115,380	244,540	224,993
Data processing and software	21,016	20,035	41,706	39,940
Other	15,493	15,378	30,867	31,081
Noninterest Expense	$ 181,860	176,890	$ 364,137	356,267
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Reclassification of Bank Card Transaction Fees [Line Items]
Bank card transaction fees		44,999		88,203
Non-interest income		123,084		240,150
Data processing and software		23,356		46,453
Other		19,761		39,725
Noninterest Expense		184,594		371,424
Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Reclassification of Bank Card Transaction Fees [Line Items]
Bank card transaction fees		(7,704)		(15,157)
Non-interest income		(7,704)		(15,157)
Data processing and software		(3,321)		(6,513)
Other		(4,383)		(8,644)
Noninterest Expense		(7,704)		(15,157)
As Adjusted for New Accounting Pronouncement [Domain]
Reclassification of Bank Card Transaction Fees [Line Items]
Bank card transaction fees		37,295		73,046
Non-interest income		115,380		224,993
Data processing and software		20,035		39,940
Other		15,378		31,081
Noninterest Expense		$ 176,890		$ 356,267