Covered Assets and FDIC Loss-sharing Asset (Changes in Allowance for Covered Loans) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Covered Assets And FDIC Loss Sharing Asset [Line Items]
Provision for loan and lease losses			$ 35,623	$ 4,029
Covered Loans [Member]
Covered Assets And FDIC Loss Sharing Asset [Line Items]
Beginning balance	20,504	5,633	4,944	6,055
Loans charged off	(1,035)	(56)	(1,597)	(56)
Recoveries	627	70	1,064	70
Provision for loan and lease losses	11,688	2,301	27,373	1,879
Ending balance	$ 31,784	$ 7,948	$ 31,784	$ 7,948