Business Disposition - Schedule of Consolidated Statements of Operations (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Total	$ 0.4	$ (108.2)	$ 38.0	$ (109.9)
Waste Management
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Net sales		20.5	4.6	42.0
Operating loss		(171.6)	(0.4)	(171.0)
Termination fee		4.0		4.0
Other expense, net		(5.8)		(7.7)
Interest expense, net		(1.2)	(0.3)	(2.4)
Loss before taxes		(174.6)	(0.7)	(177.1)
Income tax benefit		(66.4)	(0.1)	(67.2)
Net loss		(108.2)	(0.6)	(109.9)
Pre-tax gain on disposal			58.4
Income tax expense (benefit)	(0.4)		19.8
After-tax gain on disposal	0.4		38.6
Total	$ 0.4	$ (108.2)	38.0	(109.9)
Net cash provided by operating activities			2.3	8.8
Net cash used in investing activities			$ (0.1)	$ (2.6)