Covered Assets and FDIC Loss-sharing Asset (Covered OREO at Carrying Value) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Covered Assets And FDIC Loss Sharing Asset [Line Items]
Balance, end of period	$ 26,987	$ 51,019
Covered Loans [Member]
Covered Assets And FDIC Loss Sharing Asset [Line Items]
Balance, beginning of period	28,126	14,443
Established through acquisitions	0	10,387
Transfers in	14,166	15,522
OREO improvements	0	5
Additional OREO write-downs	(3,484)	(666)
Proceeds from sale of OREO property	(33,315)	(20,619)
Gain on sale of OREO	10,818	9,054
Balance, end of period	$ 16,311	$ 28,126