Revenue from Contracts with Customers Reclassification of Bank Card Transaction Fees (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Reclassification of Bank Card Transaction Fees [Line Items]
Bank card transaction fees	$ 42,427	$ 39,166	$ 127,095	$ 112,212
Non-interest income	123,714	116,887	368,254	341,880
Data processing and software	22,056	19,968	63,762	59,908
Other	16,737	15,239	47,604	46,320
Noninterest Expense	$ 185,059	179,217	$ 549,196	535,484
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Reclassification of Bank Card Transaction Fees [Line Items]
Bank card transaction fees		44,521		132,724
Non-interest income		122,242		362,392
Data processing and software		22,700		69,153
Other		17,862		57,587
Noninterest Expense		184,572		555,996
Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Reclassification of Bank Card Transaction Fees [Line Items]
Bank card transaction fees		(5,355)		(20,512)
Non-interest income		(5,355)		(20,512)
Data processing and software		(2,732)		(9,245)
Other		(2,623)		(11,267)
Noninterest Expense		(5,355)		(20,512)
As Adjusted for New Accounting Pronouncement [Domain]
Reclassification of Bank Card Transaction Fees [Line Items]
Bank card transaction fees		39,166		112,212
Non-interest income		116,887		341,880
Data processing and software		19,968		59,908
Other		15,239		46,320
Noninterest Expense		$ 179,217		$ 535,484