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Segment Information - Reconciliation of Segment Operating Income to Consolidated Loss Before Income Taxes (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating profit (loss)	$ (27.0)	$ (9.8)	$ (54.5)	$ 12.1
Interest expense	(16.4)	(7.7)	(36.4)	(19.9)
Other income (expense), net	3.0	2.3	(8.6)	3.7
Cost reduction charges	(46.1)	(31.9)	(99.0)	(69.0)	$ (82.1)	$ (118.5)
Total loss before income taxes	(40.4)	(15.2)	(99.5)	(4.1)
Other income (expense), net
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Cost reduction charges	5.7		0.6
Other income (expense), net \| Net foreign currency translation adjustment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Cost reduction charges	(5.7)		(0.6)
Operating Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating profit (loss)	48.3	44.1	113.6	142.4
Segment Reconciling Items
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Cost reduction charges	(51.8)	(31.9)	(99.6)	(69.0)
Corporate and eliminations
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating profit (loss)	$ (23.5)	$ (22.0)	$ (68.5)	$ (61.3)