Leases - Schedule of Maturities of lease liabilities (Detail) $ in Millions	Mar. 31, 2019 USD ($)
Finance Lease Liabilities, Payments, Due [Abstract]
2019	$ 1.3
2020	1.4
2021	1.2
2022	0.9
2023	0.5
Total lease payments	5.3
Less: imputed interest	(0.8)
Total future lease obligation	4.5
Operating Lease Liabilities, Payments Due [Abstract]
2019	8.2
2020	8.8
2021	7.1
2022	5.0
2023	4.1
Thereafter	8.7
Total lease payments	41.9
Less: imputed interest	(6.2)
Total future lease obligation	$ 35.7