Accrued Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Payables and Accruals [Abstract]
Accrued capital costs	$ 25,982	$ 33,105
Accrued operating expenses	11,629	12,149
Other accrued liabilities	241	4,956
Total accrued liabilities	$ 37,852	$ 50,210