Covered Assets and FDIC Loss-sharing Asset (Covered OREO at Carrying Value) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Covered Assets And FDIC Loss Sharing Asset [Line Items]
Balance, beginning of period	$ 26,987
Proceeds from sale of OREO property	(2,019)	(7,829)
Gain on sale of OREO	2,787	2,954
Total OREO, end of period	25,727
Covered Loans [Member]
Covered Assets And FDIC Loss Sharing Asset [Line Items]
Balance, beginning of period	16,311	28,126
Transfers in	1,405	2,468
Additional OREO write-down	(65)	(1,505)
Proceeds from sale of OREO property	(6,438)	(8,025)
Gain on sale of OREO	2,598	3,366
Total OREO, end of period	$ 13,811	$ 24,430