Debt - Summary Of Interest Expense (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Debt Instruments [Abstract]
Interest incurred	$ 206.1	$ 211.6	$ 220.9
Less: interest income	(4.6)	(3.7)	(6.1)
Less: interest capitalized as property, plant and equipment	(2.8)	(3.8)	(3.6)
Interest expense, net	$ 198.7	$ 204.1	$ 211.2