Covered Assets and FDIC Loss-sharing Asset (Covered OREO at Carrying Value) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended		15 Months Ended
	Sep. 30, 2012	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012
Covered Assets And FDIC Loss Sharing Asset [Line Items]
Balance, beginning of period		$ 51,019
Proceeds from sale of OREO property		(15,069)	(10,234)
Gain on sale of OREO		8,604	7,069
Total OREO, end of period	27,386	27,386		27,386
Covered Loans [Member]
Covered Assets And FDIC Loss Sharing Asset [Line Items]
Balance, beginning of period	19,079	28,126	14,443	23,730
Covered real estate acquired through foreclosure	0	0	10,387	0
Transfers in	3,096	8,497	8,071	2,979
Additional OREO write-down	(730)	(2,769)	(302)	(189)
Proceeds from sale of OREO property	(6,822)	(25,202)	(14,604)	(3,523)
Gain on sale of OREO	1,888	7,859	6,840	1,838
Total OREO, end of period	$ 16,511	$ 16,511	$ 24,835	$ 16,511