Quarterly report pursuant to Section 13 or 15(d)

Pension and Other Postretirement Benefit Programs (Details)

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Pension and Other Postretirement Benefit Programs (Details) - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2016
Mar. 31, 2015
U. S. Medical benefit plan    
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]    
Postretirement benefit expense $ 0.1 $ 0.0
Allocation of pension expense | Armstrong World Industries | U.S. defined benefit plan    
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]    
Pension plan expense 2.2 3.7
Allocation of pension expense | Armstrong World Industries | Canada defined benefit plan    
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]    
Pension plan expense 0.1 0.0
Allocation of pension expense | Armstrong World Industries | U.S. defined benefit postretirement plan    
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]    
Postretirement benefit expense $ (0.3) $ 0.1