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	9 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2019 USD ($)
Lease cost
Operating lease cost	$ 25,058	$ 74,599
Short-term lease cost	20	82
Variable lease cost	644	1,733
Sublease income	(1,903)	(5,724)
Total net lease cost	23,819	70,690
Other information
Right-of-use assets obtained in exchange for new operating lease liabilities	24,377	69,305
Cash paid toward lease liabilities	$ 25,189	$ 76,050
Weighted-average remaining lease term	7 years	7 years
Weighted-average discount rate	3.10%	3.10%