Accrued Liabilities and Other (Schedule of Accrued Liabilities and Other Balances) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Accrued Liabilities and Other [Abstract]
Accrued accounts payable invoices	$ 7,475	$ 4,070
Joint venture audit settlement	7,921	3,960
Derivative liability - current	4,244
Contingent payment	5,000
Capital expenditures	2,364	435
Stock appreciation rights - current portion	2,792	2,289
Accrued wages and other compensation	940	2,108
Other	3,041	4,322
Total accrued liabilities and other	$ 33,777	$ 17,184