Quarterly report pursuant to Section 13 or 15(d)

Commitments and Contingencies - Schedule of Letters of Credit (Details)

v3.21.2
Commitments and Contingencies - Schedule of Letters of Credit (Details) - Letter of Credit - USD ($)
$ in Thousands
Sep. 30, 2021
Dec. 31, 2020
Line of Credit Facility [Line Items]    
Total letters of credit $ 9,039 $ 13,039
Bonding program    
Line of Credit Facility [Line Items]    
Total letters of credit 1,000 5,000
Environmental remediation    
Line of Credit Facility [Line Items]    
Total letters of credit 3,694 3,694
Insurance programs    
Line of Credit Facility [Line Items]    
Total letters of credit 3,890 3,890
Rail car commitments    
Line of Credit Facility [Line Items]    
Total letters of credit $ 455 $ 455