Quarterly report pursuant to Section 13 or 15(d)

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

v3.20.1
Commitments and Contingencies - Schedule of Letters of Credit (Details) - Letter of Credit - USD ($)
$ in Thousands
Mar. 31, 2020
Dec. 31, 2019
Line of Credit Facility [Line Items]    
Total letters of credit $ 9,037 $ 8,742
Environmental remediation    
Line of Credit Facility [Line Items]    
Total letters of credit 4,477 4,182
Insurance programs    
Line of Credit Facility [Line Items]    
Total letters of credit 4,105 4,105
Rail car commitments    
Line of Credit Facility [Line Items]    
Total letters of credit $ 455 $ 455