Fixed Assets, Net - Components of Fixed Assets, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Property, Plant and Equipment
Total, cost	$ 360,161	$ 339,838
Accumulated depreciation and amortization	(193,432)	(161,803)
Total, net	166,729	178,035
Leasehold improvements, furniture and fixtures, and other fixed assets
Property, Plant and Equipment
Total, cost	254,337	245,262
Software, including software development costs
Property, Plant and Equipment
Total, cost	64,680	56,883
Computer and communications equipment
Property, Plant and Equipment
Total, cost	$ 41,144	$ 37,693