Fair Value of Assets and Liabilities (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Fair value of assets and liabilities measured on recurring basis of unobservable input reconciliation
Mortgage Servicing Rights	$ 27,904,000
Changes in Level 3 assets measured at fair value on a recurring basis
Balance at the beginning of the period	9,189,000	9,894,000
Realized and Unrealized Net Gains (Losses): Included in Net Income	35,148,000	10,935,000
Transfers to Loans Held for Sale	(29,636,000)	(11,640,000)
Balance at the end of the period	14,701,000	9,189,000
Total Unrealized Net Gains (Losses) Included in Net Income Related to Assets Still Held as of the end of the period	9,077,000	537,000
Mortgage Servicing Rights.
Changes in Level 3 assets measured at fair value on a recurring basis
Balance at the beginning of the period	7,131,000	10,226,000
Realized and Unrealized Net Gains (Losses): Included in Net Income	(2,370,000)	(3,095,000)
Balance at the end of the period	4,761,000	7,131,000
Total Unrealized Net Gains (Losses) Included in Net Income Related to Assets Still Held as of the end of the period	(863,000)	(1,521,000)
Net Derivative Assets and Liabilities
Changes in Level 3 assets measured at fair value on a recurring basis
Balance at the beginning of the period	2,058,000	(332,000)
Realized and Unrealized Net Gains (Losses): Included in Net Income	37,518,000	14,030,000
Transfers to Loans Held for Sale	(29,636,000)	(11,640,000)
Balance at the end of the period	9,940,000	2,058,000
Total Unrealized Net Gains (Losses) Included in Net Income Related to Assets Still Held as of the end of the period	9,940,000	2,058,000
Interest Rate Lock Commitments
Fair value of assets and liabilities measured on recurring basis of unobservable input reconciliation
Net Derivative Financial Instruments Not Designated as Hedging Instruments, at Fair Value	10,188,000
Fair Value Inputs Closing Ratio	88.86%
Interest Rate Swap Agreements
Fair value of assets and liabilities measured on recurring basis of unobservable input reconciliation
Net Derivative Financial Instruments Not Designated as Hedging Instruments, at Fair Value	(248,000)
Fair Value Inputs, Entity Credit Risk	0.77%
Mortgage Servicing Rights.
Fair value of assets and liabilities measured on recurring basis of unobservable input reconciliation
Assumption for Fair Value of Assets or Liabilities that relate to Transferor's Continuing Involvement, Prepayment Speed	12.26%	15.56%
Assumption for Fair Value of Assets or Liabilities that relate to Transferor's Continuing Involvement, Discount Rate	5.57%	6.31%
Branch premises
Fair value of assets and liabilities measured on recurring basis of unobservable input reconciliation
Impairment charge	$ 1,100,000	$ 600,000