Restructuring and Divestiture Costs - Schedule of Our Charges Under Both the 2015 Building Products Restructuring Plan and the 2013 Building Products Restructuring Plan (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Restructuring Cost and Reserve [Line Items]
Total	$ 23.3	$ 19.8	$ 20.8
2013 Building Products Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Severance and Plant Closing Costs	0.1	4.5
Impairment of Long-Lived Assets	0.4
Total	0.5
2015 Building Products Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Severance and Plant Closing Costs	5.0
Impairment of Long-Lived Assets	2.4
Divestitures	2.3
Total	9.7
Building Products [Member]
Restructuring Cost and Reserve [Line Items]
Severance and Plant Closing Costs	5.1
Impairment of Long-Lived Assets	2.8
Divestitures	2.3
Total	10.2	7.3	31.8
Building Products [Member] | 2013 Building Products Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Severance and Plant Closing Costs		4.5	3.2
Impairment of Long-Lived Assets		1.0	3.6
Divestitures		1.8
Total		$ 7.3	$ 6.8
Building Products [Member] | 2015 Building Products Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Severance and Plant Closing Costs	5.1
Divestitures	2.3
Total	$ 10.2