Income Taxes - Summary of components of income tax expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Taxes
Corporate tax rate	21.00%	21.00%
Current income tax (benefit) expense:
Federal		$ (1,191)
State	$ 119	57
Total current tax expense	119	(1,134)
Deferred income tax benefits:
Federal	291	1,228
State	42	36
Total deferred tax expense	333	1,264
Income tax expense	$ 452	$ 130