Transfers of Financial Assets and Mortgage Servicing Assets Transfers of Financial Assets and Mortgage Servicing Assets (Details) (USD $)	3 Months Ended			9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012	Sep. 30, 2013		Sep. 30, 2012	Dec. 31, 2012
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Number Days Required To Repurchase Mortgage Loans	90			90
Proceeds from Sale of Mortgage Loans Held-for-sale	$ 199,200,000		$ 211,900,000	$ 643,600,000		$ 510,800,000
Origination of Mortgage Servicing Rights (MSRs)	192,300,000		206,300,000	622,600,000		497,600,000
Mortgage banking activities	665,000		6,515,000	13,584,000		14,522,000
Commercial Loan [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			1,000,000	13,000,000		4,700,000
Mortgage banking activities			275,000	(315,000)		308,000
1-4 family [Member]
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Mortgage banking activities	700,000		6,200,000	13,900,000		14,200,000
Unpaid Principal Of Mortgage Loans Serviced For Investors	2,300,000,000			2,300,000,000			2,100,000,000
Bank Servicing Fees	400,000		400,000	2,500,000		1,600,000
Fair Value, Measurements, Nonrecurring [Member] | 1-4 family [Member]
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Mortgage Servicing Assets	$ 20,577,000	[1]		$ 20,577,000	[1]		$ 14,027,000	[1]

[1] The carrying amount of mortgage servicing assets is net of $0.4 million and $1.8 million reserves at September 30, 2013 and December 31, 2012, respectively. The estimated fair value does not include such adjustments.