v3.20.4
ACCRUED LIABILITIES Table - Accrued Liabilities (Details) - USD ($)
$ in Thousands
Dec. 31, 2020
Dec. 31, 2019
Accrued Liabilities, Current [Abstract]    
Employee wages and benefit costs $ 27,805 $ 36,704
Revenue contract liabilities 22,019 21,083
Interest rate swaps 0 19,169
Operating lease liabilities 10,890 10,416
Environmental costs 5,371 4,837
Other 11,685 16,401
Accrued liabilities $ 77,770 $ 108,610