Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Operating Lease, Right-of-Use Asset	$ 278,600		$ 278,600		$ 292,100
Operating Lease, Liability	310,300		310,300		$ 323,000
Lessee, Operating Lease, Liability, Payments, Due	$ 7,900	$ 8,000	24,000	$ 23,800
Significant change in expected future minimum lease payments since year end			$ 0