Segment Information - Reconciliation of Segment Operating Income to Consolidated Income (Loss) Before Income Taxes (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating income (loss)	$ 87,000,000	$ 54,000,000	$ 129,900,000	$ 155,800,000
Interest expense	(16,200,000)	(15,700,000)	(31,700,000)	(32,300,000)
Other income (expense), net	(28,900,000)	(18,000,000)	(59,300,000)	(40,600,000)
Cost-reduction (charges) benefit	(2,600,000)		(5,200,000)	0
Total income before income taxes	41,900,000	20,300,000	38,900,000	82,900,000
Operating Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating income (loss)	94,300,000	56,800,000	138,900,000	155,900,000
Segment Reconciling Items
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Cost-reduction (charges) benefit	(2,600,000)	(700,000)	(5,200,000)	2,200,000
Corporate and eliminations
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating income (loss)	$ (4,700,000)	$ (2,100,000)	$ (3,800,000)	$ (2,300,000)