Revenue and Related Matters - Schedule of Disaggregation of Revenue by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Disaggregation of Revenue [Line Items]
Total revenues	$ 1,511,041	$ 1,534,130
United States and Canada
Disaggregation of Revenue [Line Items]
Total revenues	924,305	993,829
Europe, Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	400,131	363,145
Other International
Disaggregation of Revenue [Line Items]
Total revenues	186,605	177,156
Insights
Disaggregation of Revenue [Line Items]
Total revenues	1,294,195	1,255,569
Insights | United States and Canada
Disaggregation of Revenue [Line Items]
Total revenues	771,368	791,833
Insights | Europe, Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	357,156	313,507
Insights | Other International
Disaggregation of Revenue [Line Items]
Total revenues	165,671	150,229
Conferences
Disaggregation of Revenue [Line Items]
Total revenues	78,325	72,597
Conferences | United States and Canada
Disaggregation of Revenue [Line Items]
Total revenues	57,300	55,584
Conferences | Europe, Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	11,327	9,142
Conferences | Other International
Disaggregation of Revenue [Line Items]
Total revenues	9,698	7,871
Consulting
Disaggregation of Revenue [Line Items]
Total revenues	119,129	139,706
Consulting | United States and Canada
Disaggregation of Revenue [Line Items]
Total revenues	81,084	90,964
Consulting | Europe, Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	28,290	32,303
Consulting | Other International
Disaggregation of Revenue [Line Items]
Total revenues	9,755	16,439
Other
Disaggregation of Revenue [Line Items]
Total revenues	19,392	66,258
Other | United States and Canada
Disaggregation of Revenue [Line Items]
Total revenues	14,553	55,448
Other | Europe, Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	3,358	8,193
Other | Other International
Disaggregation of Revenue [Line Items]
Total revenues	$ 1,481	$ 2,617