Financial Statements of Parent Company Guarantor - Condensed Consolidating Statement of Operations and Comprehensive Income (Loss) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Condensed Financial Statements, Captions [Line Items]
Net sales	$ 780.6	$ 754.0	$ 1,513.2	$ 1,437.3
Cost of goods sold	498.0	480.4	977.3	940.0
Gross profit	282.6	273.6	535.9	497.3
Selling, general and administrative	140.9	126.7	282.7	269.4
Research and development	19.1	17.7	37.9	36.8
Operating income	122.6	129.2	215.3	191.1
Loss (earnings) from continuing operations of investment in subsidiaries	0.0	0.0	0.0	0.0
Income (Loss) from Equity Method Investments			5.8	0.6
Other (income) expense:
Loss on sale of business	0.9	0.0	6.2	0.0
Loss on early extinguishment of debt	17.1	101.4	17.1	101.4
Net interest (income) expense	10.1	25.3	23.6	60.3
Other Income	(4.2)		(3.8)
Other expense		0.9		2.1
Income from continuing operations before income taxes	98.7	1.6	172.2	27.3
Provision for income taxes	20.8	5.0	35.9	18.0
Net income (loss) from continuing operations	77.9	(3.4)	136.3	9.3
(Loss) income from discontinued operations, net of tax	(36.4)	66.5	8.1	141.6
Gain from sale of discontinued operations, net of tax	0.0	200.6	0.0	200.6	$ (181.1)
Discontinued Operation, Income (Loss) from Investment in Subsidiaries	0.0	0.0	0.0	0.0
Comprehensive income, net of tax
Net income	41.5	263.7	144.4	351.5
Changes in cumulative translation adjustment	(22.8)	(392.6)	(25.2)	(468.3)
Changes in market value of derivative financial instruments, net of tax	4.1	(0.9)	0.3	0.7
Comprehensive income	68.4	655.4	169.9	820.5
Parent Company Guarantor
Condensed Financial Statements, Captions [Line Items]
Net sales	0.0	0.0	0.0	0.0
Cost of goods sold	0.0	0.0	0.0	0.0
Gross profit	0.0	0.0	0.0	0.0
Selling, general and administrative	8.1	4.3	13.5	2.7
Research and development	0.0	0.0	0.0	0.0
Operating income	(8.1)	(4.3)	(13.5)	(2.7)
Loss (earnings) from continuing operations of investment in subsidiaries	(88.5)	(0.9)	(152.3)	(12.0)
Other (income) expense:
Loss on sale of business	0.0		0.0
Loss on early extinguishment of debt	0.0	0.0	0.0	0.0
Net interest (income) expense	0.0	0.0	0.0	0.0
Other Income	0.0		0.0
Other expense		0.0		0.0
Income from continuing operations before income taxes	80.4	(3.4)	138.8	9.3
Provision for income taxes	2.5	0.0	2.5	0.0
Net income (loss) from continuing operations	77.9	(3.4)	136.3	9.3
(Loss) income from discontinued operations, net of tax	0.0	0.0	0.0	0.0
Gain from sale of discontinued operations, net of tax		0.0		0.0
Discontinued Operation, Income (Loss) from Investment in Subsidiaries	(36.4)	267.1	8.1	342.2
Comprehensive income, net of tax
Net income	41.5	263.7	144.4	351.5
Changes in cumulative translation adjustment	(22.8)	(392.6)	(25.2)	(468.3)
Changes in market value of derivative financial instruments, net of tax	4.1	(0.9)	0.3	0.7
Comprehensive income	68.4	655.4	169.9	820.5
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net sales	0.0	0.0	0.0	0.0
Cost of goods sold	0.0	0.0	0.0	0.0
Gross profit	0.0	0.0	0.0	0.0
Selling, general and administrative	0.0	0.1	0.0	0.2
Research and development	0.0	0.0	0.0	0.0
Operating income	0.0	(0.1)	0.0	(0.2)
Loss (earnings) from continuing operations of investment in subsidiaries	(88.1)	(1.0)	(151.6)	(12.2)
Other (income) expense:
Loss on sale of business	0.0		0.0
Loss on early extinguishment of debt	0.0	0.0	0.0	0.0
Net interest (income) expense	(0.4)	0.0	(0.7)	0.0
Other Income	0.0		0.0
Other expense		0.0		0.0
Income from continuing operations before income taxes	88.5	0.9	152.3	12.0
Provision for income taxes	0.0	0.0	0.0	0.0
Net income (loss) from continuing operations	88.5	0.9	152.3	12.0
(Loss) income from discontinued operations, net of tax	0.0	0.0	0.0	0.0
Gain from sale of discontinued operations, net of tax		0.0		0.0
Discontinued Operation, Income (Loss) from Investment in Subsidiaries	(36.4)	267.1	8.1	342.2
Comprehensive income, net of tax
Net income	52.1	268.0	160.4	354.2
Changes in cumulative translation adjustment	(22.8)	(392.6)	(25.2)	(468.3)
Changes in market value of derivative financial instruments, net of tax	4.1	(0.9)	0.3	0.7
Comprehensive income	79.0	659.7	185.9	823.2
Subsidiary Issuer
Condensed Financial Statements, Captions [Line Items]
Net sales	0.0	0.0	0.0	0.0
Cost of goods sold	0.0	0.0	0.0	0.0
Gross profit	0.0	0.0	0.0	0.0
Selling, general and administrative	0.4	0.1	0.5	0.4
Research and development	0.0	0.0	0.0	0.0
Operating income	(0.4)	(0.1)	(0.5)	(0.4)
Loss (earnings) from continuing operations of investment in subsidiaries	(138.1)	(139.2)	(189.1)	(179.1)
Other (income) expense:
Loss on sale of business	0.0		0.0
Loss on early extinguishment of debt	17.1	91.0	17.1	91.0
Net interest (income) expense	7.3	21.9	19.9	50.3
Other Income	0.0		0.0
Other expense		0.0		0.0
Income from continuing operations before income taxes	113.3	26.2	151.6	37.4
Provision for income taxes	0.0	0.0	0.0	0.0
Net income (loss) from continuing operations	113.3	26.2	151.6	37.4
(Loss) income from discontinued operations, net of tax	0.0	0.0	0.0	0.0
Gain from sale of discontinued operations, net of tax		0.0		0.0
Discontinued Operation, Income (Loss) from Investment in Subsidiaries	(36.4)	267.1	8.1	342.2
Comprehensive income, net of tax
Net income	76.9	293.3	159.7	379.6
Changes in cumulative translation adjustment	(22.8)	(392.6)	(25.2)	(468.3)
Changes in market value of derivative financial instruments, net of tax	4.1	(0.9)	0.3	0.7
Comprehensive income	103.8	685.0	185.2	848.6
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net sales	780.6	754.0	1,513.2	1,437.3
Cost of goods sold	498.0	480.4	977.3	940.0
Gross profit	282.6	273.6	535.9	497.3
Selling, general and administrative	132.4	122.2	268.7	266.1
Research and development	19.1	17.7	37.9	36.8
Operating income	131.1	133.7	229.3	194.4
Loss (earnings) from continuing operations of investment in subsidiaries	0.0	0.0	0.0	0.0
Other (income) expense:
Loss on sale of business	0.9		6.2
Loss on early extinguishment of debt	0.0	10.4	0.0	10.4
Net interest (income) expense	3.2	3.4	4.4	10.0
Other Income	(4.2)		(3.8)
Other expense		0.9		2.1
Income from continuing operations before income taxes	131.2	119.0	222.5	171.9
Provision for income taxes	18.3	5.0	33.4	18.0
Net income (loss) from continuing operations	112.9	114.0	189.1	153.9
(Loss) income from discontinued operations, net of tax	(36.4)	66.5	8.1	141.6
Gain from sale of discontinued operations, net of tax		200.6		200.6
Discontinued Operation, Income (Loss) from Investment in Subsidiaries	0.0	0.0	0.0	0.0
Comprehensive income, net of tax
Net income	76.5	381.1	197.2	496.1
Changes in cumulative translation adjustment	(22.8)	(392.6)	(25.2)	(468.3)
Changes in market value of derivative financial instruments, net of tax	4.1	(0.9)	0.3	0.7
Comprehensive income	103.4	772.8	222.7	965.1
Consolidation, Eliminations
Condensed Financial Statements, Captions [Line Items]
Net sales	0.0	0.0	0.0	0.0
Cost of goods sold	0.0	0.0	0.0	0.0
Gross profit	0.0	0.0	0.0	0.0
Selling, general and administrative	0.0	0.0	0.0	0.0
Research and development	0.0	0.0	0.0	0.0
Operating income	0.0	0.0	0.0	0.0
Loss (earnings) from continuing operations of investment in subsidiaries	314.7	141.1	493.0	203.3
Other (income) expense:
Loss on sale of business	0.0		0.0
Loss on early extinguishment of debt	0.0	0.0	0.0	0.0
Net interest (income) expense	0.0	0.0	0.0	0.0
Other Income	0.0		0.0
Other expense		0.0		0.0
Income from continuing operations before income taxes	(314.7)	(141.1)	(493.0)	(203.3)
Provision for income taxes	0.0	0.0	0.0	0.0
Net income (loss) from continuing operations	(314.7)	(141.1)	(493.0)	(203.3)
(Loss) income from discontinued operations, net of tax	0.0	0.0	0.0	0.0
Gain from sale of discontinued operations, net of tax		0.0		0.0
Discontinued Operation, Income (Loss) from Investment in Subsidiaries	109.2	(801.3)	(24.3)	(1,026.6)
Comprehensive income, net of tax
Net income	(205.5)	(942.4)	(517.3)	(1,229.9)
Changes in cumulative translation adjustment	68.4	1,177.8	75.6	1,404.9
Changes in market value of derivative financial instruments, net of tax	(12.3)	2.7	(0.9)	(2.1)
Comprehensive income	$ (286.2)	$ (2,117.5)	$ (593.8)	$ (2,636.9)