Profit Sharing Plan (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Profit Sharing Plan
Employer match contributions (as a percent)	100.00%
Employer contribution on employees' gross pay ( as a percent)	4.00%
Employer match contributions	$ 603	$ 483	$ 304
Total employer profit sharing contributions	$ 473	$ 328	$ 250