Mortgage Servicing Rights Summary of Changes in Mortgage Servicing Rights (Details) (Residential Mortgage [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Residential Mortgage [Member]
Amortized Cost:
Balance at beginning of period	$ 37,003	$ 32,809	$ 34,666	$ 30,700
Originations of mortgage servicing rights	4,341	2,213	11,177	6,881
Amortization	(2,711)	(1,343)	(7,210)	(3,902)
Balance at end of period	38,633	33,679	38,633	33,679
Valuation Allowance:
Valuation Allowance	(1,550)	(1,550)	(1,550)	(1,550)
Additions	(2,130)	0	(2,130)	0
Valuation Allowance	(3,680)	(1,550)	(3,680)	(1,550)
Net MSRs at end of period	$ 34,953	$ 32,129	$ 34,953	$ 32,129