Fixed Assets, Net - Components of Fixed Assets, Net (Details) - USD ($) $ in Thousands |
Mar. 31, 2026 |
Dec. 31, 2025 |
|---|---|---|
| Property, Plant and Equipment [Line Items] | ||
| Fixed assets, gross | $ 681,470 | $ 668,217 |
| Less: accumulated depreciation and amortization | (500,436) | (486,137) |
| Fixed assets, net | 181,034 | 182,080 |
| Computer and communications equipment | ||
| Property, Plant and Equipment [Line Items] | ||
| Fixed assets, gross | 129,539 | 126,476 |
| Software, including software development costs | ||
| Property, Plant and Equipment [Line Items] | ||
| Fixed assets, gross | 425,359 | 416,516 |
| Leasehold improvements and other fixed assets | ||
| Property, Plant and Equipment [Line Items] | ||
| Fixed assets, gross | $ 126,572 | $ 125,225 |