Fair Value Measurement, Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Loans receivable [Abstract]
Mortgage servicing rights	$ 2,091	$ 1,876
Carrying Amount [Member] | Level 1 [Member]
Financial assets [Abstract]
Cash and cash equivalents	116,032	152,892
Carrying Amount [Member] | Level 2 [Member]
Financial assets [Abstract]
Certificates of deposit	7,595	1,984
Loans receivable [Abstract]
Loans held-for-sale	2,295	1,040
Interest receivable	4,158	4,117
Financial liabilities [Abstract]
Interest payable	74	72
Carrying Amount [Member] | Level 3 [Member]
Financial assets [Abstract]
Other equity securities	6,019	5,567
Loans receivable [Abstract]
Net loans	763,393	739,112
Mortgage servicing rights	1,579	1,712
Financial liabilities [Abstract]
Deposits	1,124,612	1,104,740
Fair Value [Member] | Level 1 [Member]
Financial assets [Abstract]
Cash and cash equivalents	116,032	152,892
Fair Value [Member] | Level 2 [Member]
Financial assets [Abstract]
Certificates of deposit	7,573	1,983
Loans receivable [Abstract]
Loans held-for-sale	2,345	1,060
Interest receivable	4,158	4,117
Financial liabilities [Abstract]
Interest payable	74	72
Fair Value [Member] | Level 3 [Member]
Financial assets [Abstract]
Other equity securities	6,019	5,567
Loans receivable [Abstract]
Net loans	726,179	736,292
Mortgage servicing rights	2,091	1,876
Financial liabilities [Abstract]
Deposits	$ 966,464	$ 993,425