Fair Value Measurement, Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Assets [Abstract]
Securities available for sale	$ 69,683	$ 72,153
Level 1 [Member]
Assets [Abstract]
Cash and short-term investments	67,531	29,091
Securities available for sale	378	382
Restricted investments	0	0
Mortgage loans held for sale	0
Loans, net	0	0
Accrued interest receivable	0	0
Interest rate swaps	0	0
Bank-owned life insurance	0	0
Total assets at fair value	67,909	29,473
Liabilities [Abstract]
Deposits	0	0
FHLB advances	0	0
Junior subordinated debt	0	0
Accrued interest payable	0	0
Interest rate swaps	0	0
Total liabilities at fair value	0	0
Level 2 [Member]
Assets [Abstract]
Cash and short-term investments	0	0
Securities available for sale	69,305	71,771
Restricted investments	2,837	1,546
Mortgage loans held for sale	400
Loans, net	0	494,143
Accrued interest receivable	1,822	1,940
Interest rate swaps	444	233
Bank-owned life insurance	13,323	13,234
Total assets at fair value	88,131	582,867
Liabilities [Abstract]
Deposits	576,092	569,297
FHLB advances	37,622	7,766
Junior subordinated debt	4,019	4,116
Accrued interest payable	152	128
Interest rate swaps	63	119
Total liabilities at fair value	617,948	581,426
Level 3 [Member]
Assets [Abstract]
Cash and short-term investments	0	0
Securities available for sale	0	0
Restricted investments	0	0
Mortgage loans held for sale	0
Loans, net	482,728	46
Accrued interest receivable	0	0
Interest rate swaps	0	0
Bank-owned life insurance	0	0
Total assets at fair value	482,728	46
Liabilities [Abstract]
Deposits	0	0
FHLB advances	0	0
Junior subordinated debt	0	0
Accrued interest payable	0	0
Interest rate swaps	0	0
Total liabilities at fair value	0	0
Carrying Amount [Member]
Assets [Abstract]
Cash and short-term investments	67,236	29,300
Securities available for sale	69,683	72,153
Restricted investments	2,837	1,546
Mortgage loans held for sale	400
Loans, net	497,691	497,705
Accrued interest receivable	1,822	1,940
Interest rate swaps	444	233
Bank-owned life insurance	13,323	13,234
Total assets at fair value	653,436	616,111
Liabilities [Abstract]
Deposits	577,241	570,023
FHLB advances	37,840	7,860
Junior subordinated debt	4,124	4,124
Accrued interest payable	152	128
Interest rate swaps	63	119
Total liabilities at fair value	619,420	582,254
Fair Value [Member]
Assets [Abstract]
Cash and short-term investments	67,531	29,091
Securities available for sale	69,683	72,153
Restricted investments	2,837	1,546
Mortgage loans held for sale	400
Loans, net	482,728	494,189
Accrued interest receivable	1,822	1,940
Interest rate swaps	444	233
Bank-owned life insurance	13,323	13,234
Total assets at fair value	638,768	612,386
Liabilities [Abstract]
Deposits	576,092	569,297
FHLB advances	37,622	7,766
Junior subordinated debt	4,019	4,116
Accrued interest payable	152	128
Interest rate swaps	63	119
Total liabilities at fair value	$ 617,948	$ 581,426