Derivative Financial Instruments - Notional Amounts and Fair Values (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Derivatives designated as hedging instruments | Interest rate swaps
Notional amounts and fair values of derivatives
Notional Amount	$ 194,548	$ 194,687
Derivatives designated as hedging instruments | Interest rate swaps | Included in other assets
Notional amounts and fair values of derivatives
Asset Derivatives	29
Derivatives designated as hedging instruments | Interest rate swaps | Included in other liabilities
Notional amounts and fair values of derivatives
Liability Derivatives	(873)	(2,032)
Derivatives Not Designated as Hedging Instruments | Interest rate swaps
Notional amounts and fair values of derivatives
Notional Amount	1,988,253	1,820,442
Derivatives Not Designated as Hedging Instruments | Interest rate swaps | Included in other assets
Notional amounts and fair values of derivatives
Asset Derivatives	3,936	14,658
Derivatives Not Designated as Hedging Instruments | Interest rate swaps | Included in other liabilities
Notional amounts and fair values of derivatives
Liability Derivatives	(16,737)	(13,017)
Derivatives Not Designated as Hedging Instruments | Funding Swap (Visa Derivative)
Notional amounts and fair values of derivatives
Notional Amount	56,107	43,113
Derivatives Not Designated as Hedging Instruments | Funding Swap (Visa Derivative) | Included in other liabilities
Notional amounts and fair values of derivatives
Liability Derivatives	(4,845)	(5,439)
Derivatives Not Designated as Hedging Instruments | Foreign exchange contracts
Notional amounts and fair values of derivatives
Notional Amount	4,618	3,658
Derivatives Not Designated as Hedging Instruments | Foreign exchange contracts | Included in other assets
Notional amounts and fair values of derivatives
Asset Derivatives	2	$ 24
Derivatives Not Designated as Hedging Instruments | Foreign exchange contracts | Included in other liabilities
Notional amounts and fair values of derivatives
Liability Derivatives	$ (40)