Employee Benefit Plans - Schedule of Funded Status (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Amounts recognized in the Consolidated Balance Sheets:
Pension asset	$ 4.2	$ 1.6
Noncurrent	(266.4)	(240.2)
Defined Benefit Pension Plans
Change in benefit obligation:
Service cost	11.4	9.9
Change in plan assets:
Fair value at beginning of the year	427.4
Fair value at end of year	491.7	427.4
Defined Benefit Pension Plans | U.S.
Change in benefit obligation:
Balance at beginning of the year	62.8	66.6
Interest cost	2.5	2.7	$ 2.7
Actuarial loss (gain)	1.9	(2.3)
Benefits paid	(4.2)	(4.2)
Balance at end of the year	63.0	62.8	66.6
Change in plan assets:
Fair value at beginning of the year	45.6	47.6
Actual return on plan assets	4.0	2.1
Employer contributions	1.1	0.1
Benefits paid	(4.2)	(4.2)
Fair value at end of year	46.5	45.6	47.6
Funded status	(16.5)	(17.2)
Amounts recognized in the Consolidated Balance Sheets:
Current	(0.3)	(0.2)
Noncurrent	(16.2)	(17.0)
Total recognized in balance sheet	(16.5)	(17.2)
Accumulated other comprehensive (income) loss:
Accumulated other comprehensive loss—Actuarial loss	37.2	39.3
Total amount recognized in balance sheet and AOCI	20.7	22.1
Accumulated benefit obligations (“ABO”)	$ 63.0	$ 62.8
Defined Benefit Plan, Funding Status [Extensible List]	us-gaap:FundedPlanMember	us-gaap:FundedPlanMember
Defined Benefit Pension Plans | Foreign
Change in benefit obligation:
Balance at beginning of the year	$ 603.4	$ 578.9
Service cost	11.4	9.9	11.2
Interest cost	13.4	15.1	15.1
Participants’ contributions	1.5	1.5
Actuarial loss (gain)	9.3	35.6
Plan settlement	(0.3)
Change in currency exchange rates	73.7	(16.8)
Benefits paid	(21.2)	(20.8)
Balance at end of the year	691.2	603.4	578.9
Change in plan assets:
Fair value at beginning of the year	381.8	382.5
Actual return on plan assets	24.1	12.2
Employer contributions	16.0	15.3
Participants’ contributions	1.5	1.5
Change in currency exchange rates	43.0	(8.9)
Benefits paid	(21.2)	(20.8)
Fair value at end of year	445.2	381.8	382.5
Funded status	(246.0)	(221.6)
Amounts recognized in the Consolidated Balance Sheets:
Pension asset	4.2	1.6
Noncurrent	(250.2)	(223.2)
Total recognized in balance sheet	(246.0)	(221.6)
Accumulated other comprehensive (income) loss:
Accumulated other comprehensive loss—Actuarial loss	242.8	261.2
Accumulated other comprehensive (income) loss - Prior service credit	1.5	1.7
Accumulated other comprehensive loss, Total	244.3	262.9
Total amount recognized in balance sheet and AOCI	(1.7)	41.3
Accumulated benefit obligations (“ABO”)	$ 664.7	$ 578.8
Defined Benefit Plan, Funding Status [Extensible List]	us-gaap:FundedPlanMember	us-gaap:FundedPlanMember
OPEB
Change in benefit obligation:
Balance at beginning of the year	$ 12.2	$ 12.9
Service cost	0.1	0.1	0.1
Interest cost	0.4	0.5	0.5
Actuarial loss (gain)		(0.5)
Change in currency exchange rates	0.5	0.2
Benefits paid	(0.9)	(1.0)
Balance at end of the year	12.3	12.2	$ 12.9
Change in plan assets:
Funded status	(12.3)	(12.2)
Amounts recognized in the Consolidated Balance Sheets:
Current	(1.0)	(1.1)
Noncurrent	(11.3)	(11.1)
Total recognized in balance sheet	(12.3)	(12.2)
Accumulated other comprehensive (income) loss:
Accumulated other comprehensive loss—Actuarial loss	2.2	1.9
Accumulated other comprehensive (income) loss - Prior service credit	(5.7)	(6.8)
Accumulated other comprehensive loss, Total	(3.5)	(4.9)
Total amount recognized in balance sheet and AOCI	$ (15.8)	$ (17.1)
Defined Benefit Plan, Funding Status [Extensible List]	us-gaap:FundedPlanMember	us-gaap:FundedPlanMember