Leases - Summary of Lease Cost and Other Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Finance Lease Cost:
Amortization of right-of-use assets	$ 2,770
Interest on lease liabilities	800
Operating lease cost (includes variable and sublease costs as they are immaterial)	5,356
Short-term lease cost	932
Total lease cost	9,858
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows from finance leases	800
Operating cash flows from operating leases	6,783
Finance cash flows from finance leases	4,589	$ 3,493
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 3,017
Weighted-average remaining lease term - finance leases (years)	4 years 8 months 12 days
Weighted-average remaining lease term - operating leases (years)	6 years
Weighted-average discount rate - finance leases	3.40%
Weighted-average discount rate - operating leases	4.70%