Commitments and Contingencies (Details) (USD $) In Thousands, unless otherwise specified	1 Months Ended										3 Months Ended
	Feb. 28, 2011 Directors	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012	Mar. 31, 2013 Commitments to Extend Credit	Dec. 31, 2012 Commitments to Extend Credit	Mar. 31, 2012 Commitments to Extend Credit	Mar. 31, 2013 Standby Letters of Credit	Dec. 31, 2012 Standby Letters of Credit	Mar. 31, 2012 Standby Letters of Credit	Mar. 31, 2013 Recourse Obligation on Mortgage Loans Sold	Dec. 31, 2012 Recourse Obligation on Mortgage Loans Sold	Mar. 31, 2012 Recourse Obligation on Mortgage Loans Sold	Mar. 31, 2013 Obligation to Repurchase Receivables Sold	Dec. 31, 2012 Obligation to Repurchase Receivables Sold	Mar. 31, 2013 Obligation to Repurchase Receivables Sold Recourse Obligation on Mortgage Loans Sold
Guarantor Obligations [Line Items]
Unused commitments					$ 5,546,883	$ 5,467,998	$ 5,748,952
Guarantor obligations amount								59,715	63,085	59,798	194,242	97,706	210,789			90,772
Reserve for estimated losses arising from repurchase of loans														4,060	4,065
Recourse Period, Maximum1											120 days
Number of directors in complaint	5
Payable to FDIC for Loss Share Agreements		$ 98,870	$ 101,641	$ 82,033