Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity - Summary of AOCI Activity (Details)

v3.8.0.1
Stockholders' Equity - Summary of AOCI Activity (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
AOCI Attributable to Parent, Net of Tax [Roll Forward]      
Beginning balance $ 623.5 $ 624.0 $ 601.0
Net transfer from AWI   7.6  
Other comprehensive (loss) before reclassifications, net of tax impact (0.1) (9.7)  
Amounts reclassified from accumulated other comprehensive income (7.4) (2.1)  
Total other comprehensive (loss) 7.3 (7.6) (11.7)
Ending balance 550.0 623.5 624.0
Foreign currency translation adjustments      
AOCI Attributable to Parent, Net of Tax [Roll Forward]      
Beginning balance 0.5 0.1  
Net transfer from AWI   8.6  
Other comprehensive (loss) before reclassifications, net of tax impact 7.2 (8.2)  
Amounts reclassified from accumulated other comprehensive income 0.0 0.0  
Total other comprehensive (loss) 7.2 (8.2) (12.1)
Ending balance 7.7 0.5 0.1
AOCI tax (expense) benefit 0.0 0.0  
Derivative Adjustments      
AOCI Attributable to Parent, Net of Tax [Roll Forward]      
Beginning balance 0.5 2.3  
Net transfer from AWI   (0.2)  
Other comprehensive (loss) before reclassifications, net of tax impact (1.9) (0.6)  
Amounts reclassified from accumulated other comprehensive income (0.4) 1.0  
Total other comprehensive (loss) (1.5) (1.6) 0.6
Ending balance (1.0) 0.5 2.3
AOCI tax (expense) benefit 0.7 (0.1)  
Pension and postretirement adjustments      
AOCI Attributable to Parent, Net of Tax [Roll Forward]      
Beginning balance (60.8) (0.4)  
Net transfer from AWI   (62.6)  
Other comprehensive (loss) before reclassifications, net of tax impact (5.4) (0.9)  
Amounts reclassified from accumulated other comprehensive income (7.0) (3.1)  
Total other comprehensive (loss) 1.6 2.2 (0.2)
Ending balance (59.2) (60.8) (0.4)
AOCI tax (expense) benefit 1.2 0.5  
Accumulated other comprehensive (loss) income      
AOCI Attributable to Parent, Net of Tax [Roll Forward]      
Beginning balance (59.8) 2.0 13.7
Net transfer from AWI   (54.2)  
Total other comprehensive (loss) 7.3 (7.6) (11.7)
Ending balance (52.5) (59.8) $ 2.0
AOCI tax (expense) benefit $ 1.9 $ 0.4