Mortgage Servicing Rights Summary of Changes in Mortgage Servicing Rights (Details) (Residential Mortgage [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Residential Mortgage [Member]
Amortized Cost:
Balance at beginning of period	$ 34,666	$ 30,700
Originations of mortgage servicing rights	2,778	2,658
Amortization expense	(2,185)	(1,298)
Balance at end of period	35,259	32,060
Valuation Allowance:
Valuation Allowance	(1,550)	(1,550)
Net MSRs at end of period	$ 33,709	$ 30,510