Segment Information - Reconciliation of Segment Operating Income to Consolidated Income (Loss) Before Income Taxes (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating income (loss)	$ 70,900,000	$ 55,800,000	$ 200,800,000	$ 211,600,000
Interest expense	(15,200,000)	(15,900,000)	(46,900,000)	(48,200,000)
Other income (expense), net	(49,200,000)	(17,700,000)	(108,500,000)	(58,300,000)
Cost-reduction (charges) benefit	(200,000)		(5,400,000)	0
Total income before income taxes	6,500,000	22,200,000	45,400,000	105,100,000
Operating Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating income (loss)	71,000,000.0	53,100,000	209,900,000	209,000,000.0
Segment Reconciling Items
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Cost-reduction (charges) benefit	(200,000)	900,000	(5,400,000)	3,100,000
Corporate and eliminations
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating income (loss)	$ 100,000	$ 1,800,000	$ (3,700,000)	$ (500,000)