Operating Leases - Summary of Lease Costs for Operating Leases, Cash Paid Toward Lease Liabilities, and Weighted-Average Remaining Term and Discount Rates of Operating Leases (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($)
Lease cost
Operating lease cost	$ 24,639
Short-term lease cost	34
Variable lease cost	466
Sublease income	(1,917)
Total net lease cost	23,222
Other information
Right-of-use assets obtained in exchange for new operating lease liabilities	20,410
Cash paid toward lease liabilities	$ 25,656
Weighted-average remaining lease term	7 years
Weighted-average discount rate	3.20%