Leases - Schedule of Maturities of lease liabilities (Detail) $ in Millions	Jun. 30, 2019 USD ($)
Finance Lease Liabilities, Payments, Due [Abstract]
2019	$ 0.9
2020	1.4
2021	1.3
2022	0.9
2023	0.4
Total lease payments	4.9
Less: imputed interest	(0.7)
Total future lease obligation	4.2
Operating Lease Liabilities, Payments Due [Abstract]
2019	5.8
2020	9.3
2021	7.4
2022	5.3
2023	4.4
Thereafter	8.5
Total lease payments	40.7
Less: imputed interest	(6.0)
Total future lease obligation	$ 34.7