Segment Information - Reconciliation of Segment Operating Loss to Consolidated Loss Before Income Taxes (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating profit (loss)	$ (9.8)	$ 8.6	$ 12.1	$ (70.9)
Interest expense	(7.7)	(3.0)	(19.9)	(8.3)
Other income (expense), net	2.3	1.7	3.7	8.0
Cost reduction charges	(31.9)	(17.4)	(69.0)	(70.0)	$ (118.5)
Total income (loss) before income taxes	(15.2)	7.3	(4.1)	(71.2)
Operating Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating profit (loss)	44.1	51.5	142.4	81.4
Segment Reconciling Items
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Interest expense	(7.7)	(3.0)	(19.9)	(8.3)
Other income (expense), net	2.3	1.7	3.7	8.0
Cost reduction charges	(31.9)	(17.4)	(69.0)	(70.0)
Corporate and eliminations
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating profit (loss)	$ (22.0)	$ (25.5)	$ (61.3)	$ (82.3)