Derivative Financial Instruments - Free-Standing, Contingent Features and Counterparty Credit Risk (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		96 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Derivative financial instruments
Counterparty credit risk adjustments	$ 0	$ 100	$ 100	$ 200
Visa | Class B shares
Derivative financial instruments
Number of shares sold			274,000		0
Interest rate swaps
Derivative financial instruments
Net other interest expense	300	300	$ 600	600
Interest rate swaps | Maximum
Derivative financial instruments
Collateral thresholds for derivative agreements with credit risk related contingent features	500		500
Derivatives not designated as hedging instruments | Interest rate swaps
Derivative financial instruments
Notional Amount	1,018,305		1,018,305		$ 682,621
Positive fair value, derivative asset	31,400		31,400		10,900
Fair value loss (derivative liability)	$ 35,000		$ 35,000		$ 14,100
Derivatives not designated as hedging instruments | Interest rate swaps | Minimum
Derivative financial instruments
Fixed interest rate (as a percent)	0.47%		0.47%		1.34%
Derivatives not designated as hedging instruments | Interest rate swaps | Maximum
Derivative financial instruments
Fixed interest rate (as a percent)	4.90%		4.90%		4.90%
Derivatives not designated as hedging instruments | Interest rate swaps | Customer swap program
Derivative financial instruments
Notional Amount	$ 988,300		$ 988,300		$ 652,600
Positive fair value, derivative asset	31,400		31,400		10,900
Fair value loss (derivative liability)	31,400		31,400		$ 10,900
Upfront fees on the dealer swap	1,700	$ 0	3,700	$ 2,200
Derivatives not designated as hedging instruments | Funding Swap (Visa Derivative)
Derivative financial instruments
Notional Amount	34,475		34,475
Fair value loss (derivative liability)	$ 8,400		$ 8,400