Transfers of Financial Assets and Mortgage Servicing Rights Transfers of Financial Assets and Mortgage Servicing Rights (Details) (USD $)	3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended				3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013 Commercial Loan [Member]	Jun. 30, 2012 Commercial Loan [Member]	Jun. 30, 2013 Commercial Loan [Member]	Jun. 30, 2012 Commercial Loan [Member]	Jun. 30, 2013 1-4 family [Member]	Jun. 30, 2012 1-4 family [Member]	Jun. 30, 2013 1-4 family [Member]	Jun. 30, 2012 1-4 family [Member]	Jun. 30, 2013 Residential Mortgage Loans [Member]	Dec. 31, 2012 Residential Mortgage Loans [Member]	Jun. 30, 2013 Mortgage Banking Revenue [Member]	Jun. 30, 2012 Mortgage Banking Revenue [Member]	Jun. 30, 2013 Mortgage Banking Revenue [Member]	Jun. 30, 2012 Mortgage Banking Revenue [Member]
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Proceeds from Sale of Mortgage Loans Held-for-sale	$ 217,000,000	$ 165,300,000	$ 444,400,000	$ 298,900,000	$ 3,000,000	$ 3,700,000	$ 13,000,000	$ 3,700,000
Mortgage banking activities	5,888,000	3,624,000	12,919,000	8,007,000	(700,000)	0	(300,000)	0	6,500,000	3,600,000	13,200,000	8,000,000
Origination of Mortgage Servicing Rights (MSRs)	210,100,000	160,000,000	430,300,000	291,400,000
Mortgage Servicing Rights													2,200,000,000	2,100,000,000
Servicing Fee Income Reported In Other Non Interest Income															$ 700,000	$ 500,000	$ 2,100,000	$ 1,200,000