Employee Benefit Plans (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Employee Benefit Plans
Maximum employees' contribution (as a percent)	100.00%
Matching contribution of first 6% of eligible employees' contributions (as a percent)	50.00%
Percentage of eligible employees' contributions matched by the company	6.00%
Company's contribution	$ 828,000	$ 1,000,000.0	$ 982,000