Business and Significant Accounting Policies - Property, Equipment and Leasehold Improvements, Less Accumulated Depreciation and Amortization (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Property, Plant and Equipment [Line Items]
Property, equipment and leasehold improvements, gross	$ 610,304	$ 648,839
Less — accumulated depreciation and amortization	(396,121)	(405,871)
Property, equipment and leasehold improvements, net	214,183	242,968
Computer Equipment And Software
Property, Plant and Equipment [Line Items]
Property, equipment and leasehold improvements, gross	$ 345,968	387,362
Computer Equipment And Software | Minimum
Property, Plant and Equipment [Line Items]
Useful Life	2 years
Computer Equipment And Software | Maximum
Property, Plant and Equipment [Line Items]
Useful Life	7 years
Furniture and equipment
Property, Plant and Equipment [Line Items]
Property, equipment and leasehold improvements, gross	$ 72,462	71,026
Furniture and equipment | Minimum
Property, Plant and Equipment [Line Items]
Useful Life	3 years
Furniture and equipment | Maximum
Property, Plant and Equipment [Line Items]
Useful Life	8 years
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, equipment and leasehold improvements, gross	$ 191,874	$ 190,451
Leasehold improvements | Minimum
Property, Plant and Equipment [Line Items]
Useful Life	2 years
Leasehold improvements | Maximum
Property, Plant and Equipment [Line Items]
Useful Life	15 years