Debt - Future Maturities Of Debt (Detail) $ in Millions	Dec. 31, 2017 USD ($)
Long Term Debt Maturities
2018	$ 10.8
2019	172.2
2020	238.4
2021	529.1
2022	356.0
2023 and thereafter	816.1
Total	$ 2,122.6	[1]

[1] Excludes unamortized debt issuance costs of $11.6 million and $1.3 million of bond discount which do not represent contractual commitments with a fixed amount or maturity date.