Other Accrued Expense (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Schedule of Other Accrued Expense [Line Items]
Asset Retirement Obligation, Current	$ 33,711
Other accrued expenses	72,935	$ 81,715
Current Liabilities
Schedule of Other Accrued Expense [Line Items]
Accrued Employee Benefits, Current	14,754	23,304
Asset Retirement Obligation, Current	33,711	33,933
Accrued Environmental Loss Contingencies, Current	10,083	10,139
Operating and Finance Lease Liability, Current	7,251	7,986
Other Accrued Liabilities	7,136	6,353
Other accrued expenses	$ 72,935	$ 81,715