Commitments and Contingencies - Additional Information (Details)	9 Months Ended
Sep. 30, 2021 USD ($)
Environmental Contingency
Environmental accrual	$ 17,200,000
Expected period related to remediation expenditures for environmental contingencies period	30 years
Potential increase in environmental costs	$ 11,600,000
Time period within which recorded estimate of its obligation may change	12 months
Liability for conditional asset retirement obligations	$ 0
Minimum
Environmental Contingency
Period for final feasibility study	12 months
Maximum
Environmental Contingency
Period for final feasibility study	18 months

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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