Leases - Operating and Finance Lease Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Leases [Abstract]
Operating lease cost	$ 1,660	$ 2,700	$ 2,962
Amortization of right-of-use assets - finance leases	586	369	0
Interest expense on finance leases	915	568	0
Operating cash flows from operating leases	2,113	1,969	2,354
Operating cash flows from finance leases	$ 864	$ 533	$ 0