Accounts Payable and Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Payables and Accruals [Abstract]
Trade accounts payable	$ 40,851	$ 37,792
Accrued salaries, vacation and benefits	26,158	22,322
Other accrued expenses	24,563	28,517
Negative cash book balance	0	3,701
Accounts Payable and Accrued Liabilities, Current, Total	$ 91,572	$ 92,332