Commitments and Contingencies (Details) (USD $) In Thousands, unless otherwise specified	1 Months Ended										6 Months Ended
	Feb. 28, 2011 Directors	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2012	Jun. 30, 2013 Commitments to Extend Credit	Dec. 31, 2012 Commitments to Extend Credit	Jun. 30, 2012 Commitments to Extend Credit	Jun. 30, 2013 Standby Letters of Credit	Dec. 31, 2012 Standby Letters of Credit	Jun. 30, 2012 Standby Letters of Credit	Jun. 30, 2013 Recourse Obligation on Mortgage Loans Sold	Dec. 31, 2012 Recourse Obligation on Mortgage Loans Sold	Jun. 30, 2012 Recourse Obligation on Mortgage Loans Sold	Jun. 30, 2013 Obligation to Repurchase Receivables Sold	Dec. 31, 2012 Obligation to Repurchase Receivables Sold	Jun. 30, 2012 Obligation to Repurchase Receivables Sold	Jun. 30, 2013 Obligation to Repurchase Receivables Sold Recourse Obligation on Mortgage Loans Sold	Dec. 31, 2012 Obligation to Repurchase Receivables Sold Recourse Obligation on Mortgage Loans Sold	Jun. 30, 2012 Obligation to Repurchase Receivables Sold Recourse Obligation on Mortgage Loans Sold
Guarantor Obligations [Line Items]
Unused commitments					$ 5,737,199	$ 5,467,998	$ 5,801,224
Guarantor obligations amount								58,745	63,085	61,869	217,402	205,888	191,421				63,168	97,706	104,321
Reserve for estimated losses arising from repurchase of loans														3,916	4,065	2,849
Recourse Period, Maximum1											120 days
Number of directors in complaint	5
Payable to FDIC for loss share agreements		$ 101,652	$ 101,641	$ 91,648