Annual report pursuant to Section 13 and 15(d)

Shareholders' Equity - Summary of AOCI Activity (Details)

v3.7.0.1
Shareholders' Equity - Summary of AOCI Activity (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
AOCI Attributable to Parent, Net of Tax [Roll Forward]      
Beginning balance $ 624.0 $ 601.0 $ 576.8
Net transfer from AWI (54.2)    
Other comprehensive (loss) income before reclassifications, net of tax (9.7) (7.9)  
Amounts reclassified from accumulated other comprehensive income 2.1 (3.8)  
Total other comprehensive (loss) (7.6) (11.7) (10.0)
Ending balance 623.5 624.0 601.0
Foreign currency translation adjustments      
AOCI Attributable to Parent, Net of Tax [Roll Forward]      
Beginning balance 0.1 12.2  
Net transfer from AWI 8.6    
Other comprehensive (loss) income before reclassifications, net of tax (8.2) (12.1)  
Amounts reclassified from accumulated other comprehensive income 0.0 0.0  
Total other comprehensive (loss) (8.2) (12.1) (8.7)
Ending balance 0.5 0.1 12.2
Derivative Gain (Loss)      
AOCI Attributable to Parent, Net of Tax [Roll Forward]      
Beginning balance 2.3 1.7  
Net transfer from AWI (0.2)    
Other comprehensive (loss) income before reclassifications, net of tax (0.6) 4.4  
Amounts reclassified from accumulated other comprehensive income (1.0) (3.8)  
Total other comprehensive (loss) (1.6) 0.6 (1.1)
Ending balance 0.5 2.3 1.7
Pension and postretirement adjustments      
AOCI Attributable to Parent, Net of Tax [Roll Forward]      
Beginning balance (0.4) (0.2)  
Net transfer from AWI (62.6)    
Other comprehensive (loss) income before reclassifications, net of tax (0.9) (0.2)  
Amounts reclassified from accumulated other comprehensive income 3.1 0.0  
Total other comprehensive (loss) 2.2 (0.2) (0.2)
Ending balance (60.8) (0.4) (0.2)
Accumulated other comprehensive (loss) income      
AOCI Attributable to Parent, Net of Tax [Roll Forward]      
Beginning balance 2.0 13.7 23.7
Total other comprehensive (loss) (7.6) (11.7) (10.0)
Ending balance $ (59.8) $ 2.0 $ 13.7