Employee Benefits - Estimated Future Benefit Payments (Detail) $ in Millions	Dec. 31, 2017 USD ($)
Supplemental Plan
Schedule of Pension Expected Future Benefit Payments [Line Items]
2018	$ 8.0
2019	12.5
2020	12.7
2021	15.5
2022	14.9
2023-2027	66.8
Non U.S. Plans | Pension Plans, Defined Benefit
Schedule of Pension Expected Future Benefit Payments [Line Items]
2018	3.7
2019	3.5
2020	3.9
2021	4.2
2022	4.0
2023-2027	24.9
U.S. Plan | Pension Plans, Defined Benefit
Schedule of Pension Expected Future Benefit Payments [Line Items]
2018	77.2
2019	75.7
2020	78.0
2021	75.9
2022	74.8
2023-2027	$ 375.1