Income Taxes (Details 2) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Deferred federal income tax assets:
Allowance for loan losses	$ 9,349	$ 11,639
Postretirement benefit costs	1,078	1,090
Deferred compensation	1,095	910
Impaired loans	1,531	809
Capital loss carry-forward	596	621
Impaired investments	846	872
Accrued vacation	499	521
Allowance for real estate held for sale losses	484	195
Deferred loan origination fees and costs	251	238
Other	844	460
Total deferred federal income tax assets	16,573	17,355
Deferred federal income tax liabilities:
FHLB stock dividends	3,259	3,284
Goodwill	4,293	3,781
Mortgage servicing rights	2,742	3,043
Fixed assets	1,353	1,449
Other intangible assets	954	1,393
Loan mark to market	766	1,062
Net unrealized gains on available-for-sale securities	2,612	2,533
Other	516	384
Total deferred federal income tax liabilities	16,495	16,929
Net deferred federal income tax asset (liability)	$ 78	$ 426