Derivative Financial Instruments - Notional Amounts and Fair Values (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Interest rate swaps
Notional amounts and fair values of derivatives
Financial instruments pledged as collateral	$ 23,700	$ 12,100
Cash pledged as collateral	12,500	18,300
Derivatives designated as hedging instruments | Interest rate swaps
Notional amounts and fair values of derivatives
Notional Amount	196,173	200,504
Derivatives designated as hedging instruments | Interest rate swaps | Other liabilities
Notional amounts and fair values of derivatives
Liability Derivatives	(3,343)	(5,296)
Derivatives Not Designated as Hedging Instruments | Interest rate swaps
Notional amounts and fair values of derivatives
Notional Amount	1,727,957	1,297,101
Derivatives Not Designated as Hedging Instruments | Interest rate swaps | Other assets
Notional amounts and fair values of derivatives
Asset Derivatives	19,743	15,982
Derivatives Not Designated as Hedging Instruments | Interest rate swaps | Other liabilities
Notional amounts and fair values of derivatives
Liability Derivatives	(15,503)	(18,299)
Derivatives Not Designated as Hedging Instruments | Funding Swap (Visa Derivative)
Notional amounts and fair values of derivatives
Notional Amount	41,536	37,143
Derivatives Not Designated as Hedging Instruments | Funding Swap (Visa Derivative) | Other liabilities
Notional amounts and fair values of derivatives
Liability Derivatives	(5,975)	(7,460)
Derivatives Not Designated as Hedging Instruments | Foreign exchange contracts
Notional amounts and fair values of derivatives
Notional Amount	3,442	3,664
Derivatives Not Designated as Hedging Instruments | Foreign exchange contracts | Other assets
Notional amounts and fair values of derivatives
Asset Derivatives	88
Derivatives Not Designated as Hedging Instruments | Foreign exchange contracts | Other liabilities
Notional amounts and fair values of derivatives
Liability Derivatives	$ (12)	$ (147)