Mortgage Servicing Rights Summary of Changes in Mortgage Servicing Rights (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Jan. 31, 2011	Jan. 31, 2010
Amortization [Abstract]
2012	$ 3,008
2013	2,240
2014	1,340
2015	310
2016	43
Mortgage [Member]
Amortized Cost:
Balance at beginning of period	30,700		30,700	23,498
Originations of mortgage servicing rights	9,884	12,240
Amortization expense	(5,918)	(5,038)
Balance at end of period	34,666	30,700	30,700	23,498
Valuation Allowance:
Balance at beginning of period	(1,550)		(1,550)	(1,000)
Additions	0	(550)
Balance at end of period	(1,550)	(1,550)	(1,550)	(1,000)
Net MSRs at end of period	33,116	29,150
Valuation Allowance for Impairment of Recognized Servicing Assets, Period Increase (Decrease)	0
Amortization [Abstract]
2012	7,356
2013	6,671
2014	5,904
2015	5,051
2016	$ 4,103