Segment Reporting - Segment information (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Revenues
Interest income	$ 5,684	$ 5,709
Gain on sale of loans	1,624	928
Other revenues	873	829
Total revenues	8,181	7,466
Expenses
Provision for loan losses	400	177	$ 135
Interest expense	1,257	1,243
Salaries and benefits	3,022	2,936
Commissions	437	239
Other expenses	1,928	2,063
Total operating expenses	7,044	6,481
Income before income taxes	1,137	985
Income tax expense	239	176
Net income	898	809
Total assets	570,205	522,274	$ 540,313
Eliminations [Member]
Revenues
Interest income	(15)	0
Gain on sale of loans	0	0
Other revenues	(57)	(57)
Total revenues	(72)	(57)
Expenses
Provision for loan losses	0
Interest expense	(15)	0
Salaries and benefits	0	0
Commissions	0	0
Other expenses	(57)	(57)
Total operating expenses	(72)	(57)
Income before income taxes	0	0
Income tax expense	0	0
Net income	0	0
Total assets	(12,979)	(13,400)
Commercial Banking [Member]
Revenues
Interest income	5,590	5,646
Gain on sale of loans	0	0
Other revenues	733	774
Total revenues	6,323	6,420
Expenses
Provision for loan losses	400
Interest expense	1,257	1,243
Salaries and benefits	2,208	2,200
Commissions	0	0
Other expenses	1,709	1,882
Total operating expenses	5,574	5,325
Income before income taxes	749	1,095
Income tax expense	158	199
Net income	591	896
Total assets	570,751	525,782
Mortgage Banking [Member]
Revenues
Interest income	109	63
Gain on sale of loans	1,624	928
Other revenues	197	112
Total revenues	1,930	1,103
Expenses
Provision for loan losses	0
Interest expense	15	0
Salaries and benefits	814	736
Commissions	437	239
Other expenses	276	238
Total operating expenses	1,542	1,213
Income before income taxes	388	(110)
Income tax expense	81	(23)
Net income	307	(87)
Total assets	$ 12,433	$ 9,892