Other Noncurrent Assets - Schedule of Maturities of Lease Liabilities (Detail) $ in Millions	Jun. 30, 2019 USD ($)
Gross amounts due each year:
2019 (remainder of year)	$ 3.9
2020	6.9
2021	6.1
2022	3.5
2023	2.3
2024 and thereafter	21.5
Total lease payments	44.2
Less imputed interest	12.9
Total lease obligations	31.3
Less current obligations	6.7
Long-term lease obligations	$ 24.6