Loans and Allowance for Credit Losses Activity in the Allowance for Credit Losses (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Mar. 31, 2011
Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, Beginning Balance	$ 275,498	$ 257,553	$ 180,137	$ 271,200
Loans charged off	(161,333)	(151,425)	(119,074)
Recoveries of loans previously charged off	9,012	9,370	6,470
Net loans charged off	152,321	142,055	112,604
Provision for credit losses	135,000	160,000	190,020
Loans and Leases Receivable, Allowance, Ending Balance	$ 258,177	$ 275,498	$ 257,553	$ 271,200