Derivatives (Net Gains (Losses) on Derivatives Not Designated as Hedging Instruments) (Details) - Derivatives not designated as hedging instruments - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recognized for derivative not designated as hedging instruments	$ 4,884	$ 4,791
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	(1,779)	1,106
Foreign exchange contracts | Foreign exchange income
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recognized for derivative not designated as hedging instruments	6,326	3,857
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	83	(13)
Equity contracts | Lending fees
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recognized for derivative not designated as hedging instruments	250	(159)
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	$ 4	$ 0