Leases - Lease Cost (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Leases [Abstract]
Operating lease expense	$ 153	$ 127	$ 456	$ 376
Short-term lease expense	374	1,480	2,300	3,907
Variable lease expense	65	92	294	363
Finance lease expense:
Amortization of right-of-use assets	285	273	997	852
Interest expense on lease liabilities	228	41	680	120
Total finance lease expense	513	314	1,677	972
Total lease expense	$ 1,105	$ 2,013	4,727	5,618
Cash paid for amounts included in measurement of lease liabilities:
Operating cash flows from operating leases			469	357
Operating cash flows from finance leases			672	115
Financing cash flows from finance leases			3,499	1,003
Right-of-use assets obtained or recorded in exchange for lease obligations:
Operating leases			252	1,205
Finance leases			$ 3,326	$ 2,181