Fair Value Measurements (Details 4) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
Sep. 30, 2013	Dec. 31, 2012
Valuation methodology
Investment securities, available-for-sale	$ 834,348	$ 880,764
Recurring \| Level 3
Valuation methodology
Investment securities, available-for-sale	6,517	7,701
Recurring \| Level 3 \| Discounted cash flows \| Adjustable rate securities
Valuation methodology
Investment securities, available-for-sale	1,708	3,364
Unobservable Inputs
Term assumption	5 years	5 years
Coupon forecast assumption (as a percent)	0.37%
Recurring \| Level 3 \| Discounted cash flows \| Adjustable rate securities \| Minimum
Unobservable Inputs
Illiquidity adjustment (as a percent)	4.00%	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%	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	$ 4,809	$ 4,337
Recurring \| Level 3 \| Discounted cash flows \| Direct placement municipal securities \| Minimum
Unobservable Inputs
Credit spread assumption (as a percent)	1.16%	1.22%
Recurring \| Level 3 \| Discounted cash flows \| Direct placement municipal securities \| Maximum
Unobservable Inputs
Credit spread assumption (as a percent)	1.66%	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%
Non-recurring \| Level 3 \| Maximum \| Commercial loans
Unobservable Inputs
Discount rate (as a percent)	75.00%
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 \| Minimum \| Real estate
Unobservable Inputs
Discount rate (as a percent)	20.00%
Non-recurring \| Level 3 \| Trade publications \| Aircraft
Unobservable Inputs
Discount rate (as a percent)	10.00%

- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents Available-for-sale Securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities which are categorized as Available-for-sale.

+ References+ Details