XML 68 R51.htm IDEA: XBRL DOCUMENT v3.10.0.1
Debt (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Jun. 30, 2016
Debt Instrument [Line Items]      
Industrial revenue bonds $ 7.8 $ 7.8  
Total 279.7 256.0  
Industrial revenue bonds due 2028 [Member] | Short-term Debt [Member]      
Debt Instrument [Line Items]      
Industrial revenue bonds $ 7.8 7.8  
Stated interest rate 1.90%    
Maturity date Apr. 01, 2028    
Senior secured notes due June 01, 2021 [Member] | Long-term Debt [Member]      
Debt Instrument [Line Items]      
Senior secured notes $ 248.6 248.2  
Stated interest rate 7.50%   7.50%
Maturity date Jun. 01, 2021    
Debt discount $ 1.4 1.8  
U.S revolving credit facility [Member]      
Debt Instrument [Line Items]      
Stated interest rate 5.75%    
Maximum [Member] | Industrial revenue bonds due 2028 [Member] | Short-term Debt [Member]      
Debt Instrument [Line Items]      
Effective interest rate (percent) 12.00%    
Letter of Credit [Member]      
Debt Instrument [Line Items]      
Outstanding borrowings $ 23.3    
Letter of Credit [Member] | Short-term Debt [Member]      
Debt Instrument [Line Items]      
Outstanding borrowings $ 23.3 $ 0.0