Leases - Components of Lease Costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Finance lease expense
Amortization of ROU assets	$ 1,002	$ 1,081	$ 3,094	$ 3,495
Interest on lease liabilities	177	207	550	650
Operating lease expense	3,239	3,341	9,808	9,970
Short-term lease expense	7	11	22	60
Variable lease expense	532	(4)	1,956	441
Total	$ 4,957	$ 4,636	$ 15,430	$ 14,616