Servicing Activities and Mortgage Servicing Rights Fair Value Portfolio Characteristics (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended		12 Months Ended
	Jun. 30, 2012		Dec. 31, 2011
Servicing Assets at Fair Value [Line Items]
Outstanding Principal Balance On Loans Serviced	$ 51,548,000		$ 53,066,000
Mortgage Servicing Rights [Member]
Servicing Assets at Fair Value [Line Items]
Outstanding Principal Balance On Loans Serviced	$ 45,146,000		$ 47,818,000
Gross Weighted-Average Coupon	4.81%		4.98%
Weighted-Average Servicing Fee	0.30%		0.31%
Expected Prepayment Speed	13.89%	[1]	12.74%	[1]

[1] (1) The prepayment speed assumptions includes a blend of prepayment speeds that are influenced by mortgage interest rates, the current macroeconomic environment and borrower behaviors and may vary over the expected life of the asset.