Covered Assets and FDIC Loss-sharing Asset (FDIC Loss-sharing Asset) (Details) (FDIC Loss-sharing Asset [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
FDIC Loss-sharing Asset [Member]
Covered Assets And FDIC Loss Sharing Asset [Line Items]
Balance at beginning of period	$ 205,991	$ 0
Established through acquisitions	68,734	210,405
Cash received from the FDIC	(54,200)	(11,198)
FDIC reimbursable losses, net	4,042	1,876
Amortization, net	(46,049)	1,139
Impairment	(1,318)	4,844
Sale of other real estate	(4,346)	(1,148)
Other	2,217	73
Balance at end of period	$ 175,071	$ 205,991