Derivatives (Net Gains (Losses) on Derivatives Not Designated as Hedging Instruments) (Details) - Derivatives not designated as hedging instruments - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recognized for derivative not designated as hedging instruments	$ 2,995	$ 3,316	$ 7,879	$ 8,107
Interest rate contracts | Interest rate contracts and other derivative income
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recognized for derivative not designated as hedging instruments	(1,359)	88	(3,138)	1,194
Foreign exchange contracts | Foreign exchange income
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recognized for derivative not designated as hedging instruments	3,495	2,646	9,821	6,503
Credit contracts | Interest rate contracts and other derivative income
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recognized for derivative not designated as hedging instruments	(36)	(56)	47	(69)
Equity contracts | Lending fees
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recognized for derivative not designated as hedging instruments	917	598	1,167	439
Commodity contracts | Interest rate contracts and other derivative income
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recognized for derivative not designated as hedging instruments	$ (22)	$ 40	$ (18)	$ 40