v3.26.1
Revenue and Related Matters - Schedule of Timing of Revenue Recognition Liabilities per Segment (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Disaggregation of Revenue [Line Items]        
Total revenues $ 1,675,943 $ 1,686,454 $ 3,186,984 $ 3,220,584
Transferred over time        
Disaggregation of Revenue [Line Items]        
Total revenues 1,383,450 1,370,793 2,765,936 2,727,533
Transferred at a point in time        
Disaggregation of Revenue [Line Items]        
Total revenues 292,493 315,661 421,048 493,051
Insights        
Disaggregation of Revenue [Line Items]        
Total revenues 1,289,870 1,263,505 2,584,065 2,519,074
Insights | Transferred over time        
Disaggregation of Revenue [Line Items]        
Total revenues 1,287,650 1,260,549 2,579,903 2,512,737
Insights | Transferred at a point in time        
Disaggregation of Revenue [Line Items]        
Total revenues 2,220 2,956 4,162 6,337
Conferences        
Disaggregation of Revenue [Line Items]        
Total revenues 244,157 211,407 322,482 284,004
Conferences | Transferred over time        
Disaggregation of Revenue [Line Items]        
Total revenues 0 0 0 0
Conferences | Transferred at a point in time        
Disaggregation of Revenue [Line Items]        
Total revenues 244,157 211,407 322,482 284,004
Consulting        
Disaggregation of Revenue [Line Items]        
Total revenues 141,916 155,594 261,045 295,300
Consulting | Transferred over time        
Disaggregation of Revenue [Line Items]        
Total revenues 95,800 109,882 185,959 214,034
Consulting | Transferred at a point in time        
Disaggregation of Revenue [Line Items]        
Total revenues $ 46,116 45,712 75,086 81,266
Other        
Disaggregation of Revenue [Line Items]        
Total revenues   55,948 19,392 122,206
Other | Transferred over time        
Disaggregation of Revenue [Line Items]        
Total revenues   362 74 762
Other | Transferred at a point in time        
Disaggregation of Revenue [Line Items]        
Total revenues   $ 55,586 $ 19,318 $ 121,444