Leases - Components of Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Operating lease costs
Single lease costs	$ 1,029	$ 1,046
Variable lease costs	427	419
Sublease income:
Sublease income	(475)	(467)
Total operating lease costs	$ 981	$ 998