Loans and Allowance for Loan Losses (Details 6) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Allowance for Covered Loan Losses [Roll Forward]
Balance at beginning of period	$ 114,690	$ 115,092	$ 103,757
Net provision for loan losses, covered	62,900	83,783	98,433
Loans charged off		(104,532)	(99,713)
Balance at end of period	107,699	114,690	115,092
Covered Loans [Member]
Allowance for Covered Loan Losses [Roll Forward]
Balance at beginning of period	13,733	0
Provision for loan losses before benefit attributable to FDIC loss share agreements	62,905	27,184
Benefit attributable to FDIC loss share agreements	(42,552)	(22,752)
Net provision for loan losses, covered	20,353	4,432
Increase in indemnification asset	42,552	22,752
Loans charged off	(40,221)	(13,451)
Balance at end of period	$ 36,417	$ 13,733