Accrued Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Accrued Liabilities
Employee accrued compensation expense	$ 3,620	$ 7,130
Other accrued liabilities	12,022	18,482
Accrued interest on debt	9,767	9,718
Total accrued liabilities	$ 25,409	$ 35,330