Commitments and Contingencies - Summary of Net Asbestos Charges (Detail) - Asbestos Related Matters [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Asbestos Related Contingencies [Line Items]
Asbestos provision	$ 56.5	$ 59.0
Asbestos remeasurement, net	(76.4)	(81.8)
Change in Defense Cost Estimate for Asbestos Matters	0.0	4.9
Settlement Agreement	0.0	(2.1)
Continuing Operations [Member]
Asbestos Related Contingencies [Line Items]
Asbestos provision	56.5	59.0	$ 63.0
Asbestos remeasurement, net	(76.4)	(81.8)	(44.8)
Change in Defense Cost Estimate for Asbestos Matters	0.0	(4.9)	(100.7)
Settlement Agreement	0.0	2.1	(8.9)
Net asbestos charge	$ (19.9)	$ (25.6)	$ (91.4)