Covered Assets and FDIC Loss-sharing Asset (Covered OREO at Carrying Value) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Covered Assets And FDIC Loss Sharing Asset [Line Items]
Balance, beginning of period	$ 51,019
Proceeds from sale of OREO property	(7,829)	(5,372)
Gain on sale of OREO	2,954	2,712
Total OREO, end of period	41,174
Covered Loans [Member]
Covered Assets And FDIC Loss Sharing Asset [Line Items]
Balance, beginning of period	28,126	14,443
Transfers in	2,468	3,425
Additional OREO write-down	(1,505)	(15)
Proceeds from sale of OREO property	(8,025)	(6,959)
Gain on sale of OREO	3,366	2,633
Total OREO, end of period	$ 24,430	$ 13,527