XML 127 R79.htm IDEA: XBRL DOCUMENT v3.20.4
Accrued Liabilities (Details) - USD ($)
$ in Millions
Dec. 31, 2020
Dec. 31, 2019
Balance Sheet Related Disclosures [Abstract]    
Accrued benefits $ 18.3 $ 21.7
Current portion of postretirement benefit obligation 2.8 2.9
Other taxes payable 9.8 9.9
Current portion of black lung liability 4.6 4.6
Accrued legal 6.4 2.7
Other 7.9 5.5
Total accrued liabilities $ 49.8 $ 47.3