Covered Assets and FDIC Indemnification Asset (Summary of Activity in Covered Other Real Estate Owned) (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Covered Assets and FDIC Indemnification Asset
Balance, beginning of period	$ 27,689,000.000	$ 8,995,000.000	$ 29,863,000.000
Acquisition		17,938,000.000		26,939,000.000
Additions to covered OREO	5,632,000.000	2,560,000.000	8,668,000.000	2,669,000.000
Dispositions of covered OREO	(2,503,000.000)	(1,198,000.000)	(6,457,000.000)	(1,313,000.000)
Valuation adjustments in the period	(665,000.000)	(5,000.000)	(1,921,000.000)	(5,000.000)
Balance, end of period	$ 30,153,000.000	$ 28,290,000.000	$ 30,153,000.000	$ 28,290,000.000