Employee Benefit and Retirement Plans - Schedule of Estimated Future Benefit Payments Under Defined Denefit Pension Plans and Postretirement Benefit Plans (Detail) $ in Millions	Dec. 31, 2017 USD ($)
Pension Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2018	$ 127.8
2019	126.9
2020	128.9
2021	128.6
2022	128.1
Thereafter	627.6
Postretirement Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2018	5.9
2019	5.9
2020	5.8
2021	5.8
2022	5.7
Thereafter	$ 24.5