Income Taxes - Components of income tax expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Current
Federal	$ 62	$ 64
State	954	812
Total current	1,016	876
Deferred income tax (liabilities) benefits:
Federal	1,509	1,587
State	106	(104)
Total deferred	1,615	1,483
Income tax expense	$ 2,631	$ 2,359