Income Taxes - Components of net deferred income tax benefits (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred income tax benefits:
Accrued deferred compensation	$ 87	$ 78
Allowance for credit losses	243	347
Net operating loss carryforward credits	153	345
Accumulated depreciation	(13)
Accumulated depreciation		4
Reserve for unfunded commitments	10	10
Accounting standard 310-20	(103)	(76)
Right of use asset	(205)
Lease liability	205
Other temporary differences		7
Accumulated securities premium accretion	215	210
Net unrealized depreciation on investment securities available for sale	80	467
Net deferred income tax benefits	$ 672	$ 1,392