Lease Accounting - Quantitative Information Regarding Other Information (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2019 USD ($)
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from finance leases	$ 0.0
Operating cash flows from operating leases	4.3
Financing cash flows from finance leases	$ 0.0
Weighted average remaining lease term - finance leases	3 years 6 months
Weighted average remaining lease term - operating leases	4 years 4 months 24 days
Average discount rate - finance leases	5.50%
Average discount rate - operating leases	3.43%