v3.26.3
Revenue and Related Matters - Schedule of Disaggregation of Revenue by Geographic Area (Details) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Disaggregation of Revenue [Line Items]        
Total revenues $ 1,504,791 $ 1,524,072 $ 4,691,775 $ 4,744,656
United States and Canada        
Disaggregation of Revenue [Line Items]        
Total revenues 884,267 907,568 2,832,824 2,957,819
Europe, Middle East and Africa        
Disaggregation of Revenue [Line Items]        
Total revenues 419,694 418,727 1,277,995 1,209,780
Other International        
Disaggregation of Revenue [Line Items]        
Total revenues 200,830 197,777 580,956 577,057
Insights        
Disaggregation of Revenue [Line Items]        
Total revenues 1,292,434 1,270,724 3,876,499 3,789,798
Insights | United States and Canada        
Disaggregation of Revenue [Line Items]        
Total revenues 775,737 770,945 2,316,631 2,342,406
Insights | Europe, Middle East and Africa        
Disaggregation of Revenue [Line Items]        
Total revenues 353,260 340,492 1,065,438 977,139
Insights | Other International        
Disaggregation of Revenue [Line Items]        
Total revenues 163,437 159,287 494,430 470,253
Conferences        
Disaggregation of Revenue [Line Items]        
Total revenues 86,003 74,554 408,485 358,558
Conferences | United States and Canada        
Disaggregation of Revenue [Line Items]        
Total revenues 21,422 11,433 240,981 205,302
Conferences | Europe, Middle East and Africa        
Disaggregation of Revenue [Line Items]        
Total revenues 38,789 39,356 115,027 103,793
Conferences | Other International        
Disaggregation of Revenue [Line Items]        
Total revenues 25,792 23,765 52,477 49,463
Consulting        
Disaggregation of Revenue [Line Items]        
Total revenues 126,354 123,573 387,399 418,873
Consulting | United States and Canada        
Disaggregation of Revenue [Line Items]        
Total revenues 87,108 78,299 260,659 261,042
Consulting | Europe, Middle East and Africa        
Disaggregation of Revenue [Line Items]        
Total revenues 27,645 32,987 94,172 108,086
Consulting | Other International        
Disaggregation of Revenue [Line Items]        
Total revenues $ 11,601 12,287 32,568 49,745
Other        
Disaggregation of Revenue [Line Items]        
Total revenues   55,221 19,392 177,427
Other | United States and Canada        
Disaggregation of Revenue [Line Items]        
Total revenues   46,891 14,553 149,069
Other | Europe, Middle East and Africa        
Disaggregation of Revenue [Line Items]        
Total revenues   5,892 3,358 20,762
Other | Other International        
Disaggregation of Revenue [Line Items]        
Total revenues   $ 2,438 $ 1,481 $ 7,596