Leases - Cash Payments Included in Measurement of Lease Liabilities (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Finance leases:
Operating cash flows included in operating activities	$ 113	$ 132
Financing cash flows included in payments under finance lease obligations	712	905
Operating leases:
Operating cash flows (fixed payments) included in other operating activities, net	2,267	2,493
Operating cash flows (liability reduction) included in other operating activities, net	$ 1,954	$ 1,949