Fixed Assets, Net - Schedule of Components of Fixed Assets, Net (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Property, Plant and Equipment
Total, cost	$ 393,061	$ 388,269
Accumulated depreciation and amortization	(238,637)	(231,779)
Total, net	154,424	156,490
Leasehold improvements, furniture and fixtures, and other fixed assets
Property, Plant and Equipment
Total, cost	267,662	266,585
Software, including software development costs
Property, Plant and Equipment
Total, cost	78,252	76,567
Computer and communications equipment
Property, Plant and Equipment
Total, cost	$ 47,147	$ 45,117