Derivative Financial Instruments - Notional Amounts and Fair Values (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Derivatives designated as hedging instruments | Interest rate swaps
Notional amounts and fair values of derivatives
Notional Amount	$ 194,687	$ 200,504
Derivatives designated as hedging instruments | Interest rate swaps | Other liabilities
Notional amounts and fair values of derivatives
Liability Derivatives	(2,032)	(5,296)
Derivatives Not Designated as Hedging Instruments | Interest rate swaps
Notional amounts and fair values of derivatives
Notional Amount	1,820,442	1,297,101
Derivatives Not Designated as Hedging Instruments | Interest rate swaps | Other assets
Notional amounts and fair values of derivatives
Asset Derivatives	14,658	15,982
Derivatives Not Designated as Hedging Instruments | Interest rate swaps | Other liabilities
Notional amounts and fair values of derivatives
Liability Derivatives	(13,017)	(18,299)
Derivatives Not Designated as Hedging Instruments | Funding Swap (Visa Derivative)
Notional amounts and fair values of derivatives
Notional Amount	43,113	37,143
Derivatives Not Designated as Hedging Instruments | Funding Swap (Visa Derivative) | Other liabilities
Notional amounts and fair values of derivatives
Liability Derivatives	(5,439)	(7,460)
Derivatives Not Designated as Hedging Instruments | Foreign exchange contracts
Notional amounts and fair values of derivatives
Notional Amount	3,658	3,664
Derivatives Not Designated as Hedging Instruments | Foreign exchange contracts | Other assets
Notional amounts and fair values of derivatives
Asset Derivatives	$ 24
Derivatives Not Designated as Hedging Instruments | Foreign exchange contracts | Other liabilities
Notional amounts and fair values of derivatives
Liability Derivatives		$ (147)