Derivative Financial Instruments - Derivatives Not Designated as Hedges (Details) - Derivatives Not Designated as Hedging Instruments - Other noninterest income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Interest rate swaps
Impact on pretax earnings of derivatives not designated as hedges
Net Gains (Losses) on Derivatives	$ 404	$ 253
Funding Swap (Visa Derivative)
Impact on pretax earnings of derivatives not designated as hedges
Net Gains (Losses) on Derivatives	(84)	3
Foreign exchange contracts
Impact on pretax earnings of derivatives not designated as hedges
Net Gains (Losses) on Derivatives	$ (63)	$ 205