Lease Accounting - Quantitative Information Regarding Other Information (Detail) $ in Millions	6 Months Ended
	Jun. 30, 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	8.5
Financing cash flows from finance leases	$ 0.0
Weighted average remaining lease term - finance leases (in years)	3 years 3 months 18 days
Weighted average remaining lease term - operating leases (in years)	4 years 3 months 3 days
Average discount rate - finance leases	5.50%
Average discount rate - operating leases	3.46%