Portfolio Loans Covered by Loss Share (Covered loans) - Summary of Changes in Accretable Yield for Purchased Loans (Details) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Estimated Clawback Liability	$ 879,000
Adjustment in FDIC clawback liability	304,000
Summary of Changes in Accretable Yield for Purchased Loans [Roll Forward]
Balance at beginning of period	78,768,000	63,335,000
Accretion	(7,112,000)	(7,082,000)
Disposals of Covered Loans	(5,956,000)	(1,315,000)
Reclassifications from nonaccretable difference	599,000	45,386,000
Other	0	322,000
Balance at end of period	66,299,000	100,646,000
Net cash proceeds received from FDIC loss share receivable	$ 1,685,000	$ 11,614,000