Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Jan. 01, 2019
Operating Lease, Right-of-Use Asset	$ 298,600		$ 298,600		$ 297,700	$ 170,500
Operating Lease, Liability	328,900		328,900		$ 323,700	$ 174,400
Lessee, Operating Lease, Liability, Payments, Due	$ 8,000	$ 7,600	23,800	$ 19,700
Significant change in expected future minimum lease payments since year end			$ 0