XML 112 R93.htm IDEA: XBRL DOCUMENT v3.20.4
Leases - Supplemental Balance Sheet Information (Details) - USD ($)
$ in Millions
Dec. 31, 2020
Dec. 31, 2019
Operating leases:    
Operating lease right-of-use assets $ 49.9 $ 82.4
Accounts payable and accrued expenses 24.5 29.6
Operating lease liabilities, less current portion 42.1 52.8
Total operating lease liabilities $ 66.6 $ 82.4
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List] us-gaap:AccountsPayableAndAccruedLiabilitiesCurrent us-gaap:AccountsPayableAndAccruedLiabilitiesCurrent
Finance leases:    
Property, plant, equipment and mine development $ 20.4 $ 89.6
Accumulated depreciation (2.5) (45.9)
Property, plant, equipment and mine development, net 17.9 43.7
Current portion of long-term debt 21.5 14.3
Long-term debt, less current portion 5.8 0.9
Total finance lease liabilities $ 27.3 $ 15.2
Weighted average remaining lease term (years)    
Operating leases 3 years 4 months 24 days 3 years 9 months 18 days
Finance leases 9 years 7 months 6 days
Weighted average discount rate    
Operating leases 6.80% 7.30%
Finance leases 11.20% 6.00%