Fair Value of Assets and Liabilities (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Changes in Level 3 assets and liabilities measured at fair value on a recurring basis
Balance at the beginning of the period	$ 14,701	$ 9,189
Realized and Unrealized Net Gains (Losses): Included in Net Income	2,953	3,012
Transfers to Loans Held for Sale	(8,240)	(3,726)
Balance at the end of the period	9,414	8,475
Total Unrealized Net Gains (Losses) Included in Net Income Related to Assets Still Held as of the end of the period	5,012	1,739
Mortgage Servicing Rights
Changes in Level 3 assets and liabilities measured at fair value on a recurring basis
Balance at the beginning of the period	4,761	7,131
Realized and Unrealized Net Gains (Losses): Included in Net Income	(325)	(708)
Balance at the end of the period	4,436	6,423
Total Unrealized Net Gains (Losses) Included in Net Income Related to Assets Still Held as of the end of the period	34	(313)
Net Derivative Assets and Liabilities
Changes in Level 3 assets and liabilities measured at fair value on a recurring basis
Balance at the beginning of the period	9,940	2,058
Realized and Unrealized Net Gains (Losses): Included in Net Income	3,278	3,720
Transfers to Loans Held for Sale	(8,240)	(3,726)
Balance at the end of the period	4,978	2,052
Total Unrealized Net Gains (Losses) Included in Net Income Related to Assets Still Held as of the end of the period	$ 4,978	$ 2,052