Leases - Schedule of Other Information Reported in Condensed Consolidated Statement of Cash Flows (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows from operating leases	$ 10.1
Operating cash flows from finance leases	0.9
Financing cash flows from finance leases	6.3	$ 5.9
Assets obtained in exchange for lease obligations:
Adoption of accounting principal ASC 842	82.3
Operating leases	10.8
Finance leases	0.6	$ 9.4
ASU 2016-02 [Member]
Assets obtained in exchange for lease obligations:
Adoption of accounting principal ASC 842	$ 82.3