Income Taxes (Details 2) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred federal income tax assets:
Allowance for loan losses	$ 5,802	$ 5,415
Postretirement benefit costs	473	671
Deferred compensation	1,011	1,354
Impaired loans	1,154	1,432
Accrued vacation	11	123
Allowance for real estate held for sale losses	62	71
Deferred loan origination fees and costs	435	332
Accrued bonus	638	333
Net unrealized gains on available-for-sale securities	547	0
Other	1,273	1,578
Total deferred federal income tax assets	11,406	11,309
Deferred federal income tax liabilities:
FHLB stock dividends	1,558	1,558
Goodwill	4,584	4,377
Mortgage servicing rights	2,125	2,060
Fixed assets	2,046	1,039
Other intangible assets	778	990
Loan mark to market	7	5
Net unrealized gains on available-for-sale securities	0	194
Prepaid expenses	550	539
Other	22	316
Total deferred federal income tax liabilities	11,670	11,078
Net deferred federal income tax asset		231
Net deferred federal income tax liability	$ (264)	$ 0