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	6 Months Ended
	Jun. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)
Lease cost
Operating lease cost	$ 24,902	$ 49,541
Short-term lease cost	28	62
Variable lease cost	623	1,089
Sublease income	(1,904)	(3,821)
Total net lease cost	23,649	46,871
Other information
Right-of-use assets obtained in exchange for new operating lease liabilities	24,518	44,928
Cash paid toward lease liabilities	$ 25,205	$ 50,861
Weighted-average remaining lease term	7 years	7 years
Weighted-average discount rate	3.20%	3.20%