Loans Changes in Loss Share Receivable Associated with Covered Loans (Details) (USD $)				3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012	Mar. 31, 2013 Loss Share Receivable [Member]	Mar. 31, 2012 Loss Share Receivable [Member]	Mar. 31, 2011 Loss Share Receivable [Member]
Changes in Loss Share Receivable [Roll Forward]
Balance at beginning of period					$ 113,734,000	$ 205,664,000
Accretion				(8,104,000)	(9,657,000)
Increase due to impairment				5,539,000	4,899,000
FDIC reimbursement				(10,549,000)	(27,430,000)
Covered loans paid in full				(5,027,000)	(2,340,000)
Balance at end of period	$ 95,593,000	$ 113,734,000	$ 171,136,000	$ 95,593,000	$ 171,136,000