Commitments and Contingencies (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	1 Months Ended							6 Months Ended
	Feb. 28, 2011 Directors	Jun. 30, 2012 Commitments to Extend Credit	Dec. 31, 2011 Commitments to Extend Credit	Jun. 30, 2011 Commitments to Extend Credit	Jun. 30, 2012 Standby Letters of Credit	Dec. 31, 2011 Standby Letters of Credit	Jun. 30, 2011 Standby Letters of Credit	Jun. 30, 2012 Recourse Obligation on Mortgage Loans Sold	Dec. 31, 2011 Recourse Obligation on Mortgage Loans Sold	Jun. 30, 2011 Recourse Obligation on Mortgage Loans Sold	Jun. 30, 2012 Obligation to Repurchase Receivables Sold	Jun. 30, 2012 Obligation to Repurchase Receivables Sold Recourse Obligation on Mortgage Loans Sold
Guarantor Obligations [Line Items]
Unused commitments		$ 5,801,224	$ 5,636,942	$ 5,801,539
Guarantor obligations amount					61,869	57,446	69,969	191,421	207,963	147,572		104,321
Reserve for estimated losses arising from repurchase of loans											$ 2,849
General maximum recourse period, days								120 days
Number of directors in complaint	5