Revenue - Schedule of Contract Liabilities (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Contract with Customer, Liability [Roll Forward]
Balance, beginning of period	$ 7,244	$ 4,304
Deduction for recognition of revenue	(9,897)	(4,827)
Increase for deferral of shortfall payments	12,036	8,442
Increase for deferral of customer prepayments	212	675
Deduction of shortfall payments due to contract renegotiations		(1,350)
Balance, end of period	$ 9,595	$ 7,244