Commitments and Contingencies Outstanding Commitments to Extend Credit and Letters of Credit (Details) (USD $)	3 Months Ended	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 Commitments to Extend Credit [Member] Reserve for Off-balance Sheet Activities [Member]	Dec. 31, 2011 Commitments to Extend Credit [Member] Reserve for Off-balance Sheet Activities [Member]	Sep. 30, 2012 Standby Letters of Credit [Member] Reserve for Off-balance Sheet Activities [Member]	Dec. 31, 2011 Standby Letters of Credit [Member] Reserve for Off-balance Sheet Activities [Member]	Sep. 30, 2012 Commercial Letters of Credit [Member] Reserve for Off-balance Sheet Activities [Member]	Dec. 31, 2011 Commercial Letters of Credit [Member] Reserve for Off-balance Sheet Activities [Member]	Sep. 30, 2012 Residential Mortgage [Member] Reserve for Off-balance Sheet Activities [Member]	Dec. 31, 2011 Residential Mortgage [Member] Reserve for Off-balance Sheet Activities [Member]
ResidentialMortgagePrincipalBalanceRepurchaseRequestReceived		$ 5,900,000	$ 2,700,000
ResidentialMortgagePrincipalBalanceFHLBCreditEnhancement	248,000,000
ResidentialMortgageRepurchaseReservesFHLBCreditEnhancement		3,000,000
Valuation allowances and Reserves, Balance				$ 4,007,947,000	$ 3,803,532,000	$ 427,697,000	$ 444,019,000	$ 27,305,000	$ 31,557,000	$ 4,600,000	$ 1,500,000