Fair Value Measurements (Details 4) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Valuation methodology
Investment securities, available-for-sale	$ 832,700	$ 880,764
Recurring | Level 3
Valuation methodology
Investment securities, available-for-sale	5,498	7,701
Recurring | Level 3 | Discounted cash flows | Adjustable rate securities
Valuation methodology
Investment securities, available-for-sale		3,364
Unobservable Inputs
Term assumption		5 years	[1]
Recurring | Level 3 | Discounted cash flows | Adjustable rate securities | Minimum
Unobservable Inputs
Illiquidity adjustment (as a percent)		4.00%
Coupon forecast assumption (as a percent)		0.50%
Recurring | Level 3 | Discounted cash flows | Adjustable rate securities | Maximum
Unobservable Inputs
Illiquidity adjustment (as a percent)		8.00%
Coupon forecast assumption (as a percent)		0.88%
Recurring | Level 3 | Discounted cash flows | Direct placement municipal securities
Valuation methodology
Investment securities, available-for-sale	$ 5,498	$ 4,337
Recurring | Level 3 | Discounted cash flows | Direct placement municipal securities | Minimum
Unobservable Inputs
Credit spread assumption (as a percent)	0.90%	1.22%
Recurring | Level 3 | Discounted cash flows | Direct placement municipal securities | Maximum
Unobservable Inputs
Credit spread assumption (as a percent)	1.52%	1.95%
Non-recurring | Level 3 | Commercial loans
Unobservable Inputs
Discount rate (as a percent)	20.00%
Non-recurring | Level 3 | Minimum | Commercial loans
Unobservable Inputs
Discount rate (as a percent)	40.00%	40.00%
Non-recurring | Level 3 | Maximum | Commercial loans
Unobservable Inputs
Discount rate (as a percent)	75.00%	75.00%
Non-recurring | Level 3 | Trade publications | Aircraft
Unobservable Inputs
Discount rate (as a percent)	10.00%
Non-recurring | Level 3 | Auction values | Autos
Unobservable Inputs
Discount rate (as a percent)	10.00%
Non-recurring | Level 3 | Trade publications and auction values | Medium and heavy duty trucks
Unobservable Inputs
Discount rate (as a percent)	15.00%
Non-recurring | Level 3 | Trade publications and auction values | Construction and environmental equipment
Unobservable Inputs
Discount rate (as a percent)	20.00%
Non-recurring | Level 3 | Appraisals | Real estate
Unobservable Inputs
Discount rate (as a percent)	20.00%

[1] Term assumption is influenced by security call history