Disclosures About Fair Value of Assets and Liabilities - Unobservable Inputs Used in Recurring and Nonrecurring Level 3 Fair Value Measurements Other Than Goodwill (Details) (USD $) In Thousands, unless otherwise specified			9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013 Discounted Cash Flow State and municipal Minimum	Sep. 30, 2013 Discounted Cash Flow State and municipal Maximum	Sep. 30, 2013 Discounted Cash Flow Corporate obligations	Sep. 30, 2013 Collateral Based Measurements Impaired loans (collateral dependent) Minimum	Sep. 30, 2013 Collateral Based Measurements Impaired loans (collateral dependent) Maximum	Sep. 30, 2013 Appraisals Other real estate owned Minimum	Sep. 30, 2013 Appraisals Other real estate owned Maximum	Sep. 30, 2013 Significant Unobservable Inputs (Level 3) Discounted Cash Flow State and municipal	Sep. 30, 2013 Significant Unobservable Inputs (Level 3) Discounted Cash Flow Corporate obligations	Sep. 30, 2013 Significant Unobservable Inputs (Level 3) Collateral Based Measurements Impaired loans (collateral dependent)	Sep. 30, 2013 Significant Unobservable Inputs (Level 3) Appraisals Other real estate owned
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value	$ 606,341	$ 513,343								$ 20,510	$ 488
Fair Value												$ 8,874	$ 8,220
Maturity/Call date			1 month	10 years
Blend of US Muni BQ curve			A-	BBB-
Discount rate			1.00%	5.00%
Risk free rate					3 month LIBOR
Discount to reflect current market conditions and ultimate collectability						0.00%	50.00%
Discount to reflect current market conditions					2.00%			0.00%	20.00%