v3.26.1
Segment Information - Schedule of Reconciliation of Segment Gross Contribution to Net Income (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Segment Reporting [Line Items]        
Revenues $ 1,675,943 $ 1,686,454 $ 3,186,984 $ 3,220,584
Personnel expenses 375,724 404,917 743,539 791,116
Product and content delivery expenses 84,701 107,547 127,501 176,157
Other expenses 17,154 16,372 31,272 30,396
Gross contribution 1,198,364 1,157,618 2,284,672 2,222,915
Cost of services and product development - unallocated 9,330 2,895 13,904 9,092
Selling, general and administrative 764,592 776,888 1,490,941 1,507,196
Depreciation and amortization 45,183 50,739 90,614 101,499
Gain from sale of divested operation 739 0 (5,399) 0
Interest expenses and other, net 23,897 9,303 47,577 20,327
Income before income taxes 354,623 317,793 647,035 584,801
Insights        
Segment Reporting [Line Items]        
Revenues 1,289,870 1,263,505 2,584,065 2,519,074
Conferences        
Segment Reporting [Line Items]        
Revenues 244,157 211,407 322,482 284,004
Consulting        
Segment Reporting [Line Items]        
Revenues 141,916 155,594 261,045 295,300
Other        
Segment Reporting [Line Items]        
Revenues   55,948 $ 19,392 $ 122,206
Maximum        
Segment Reporting [Line Items]        
Percent of target bonus charges allocated to segments     100.00% 100.00%
Operating Segments | Insights        
Segment Reporting [Line Items]        
Revenues 1,289,870 1,263,505 $ 2,584,065 $ 2,519,074
Personnel expenses 275,672 289,436 547,630 568,427
Product and content delivery expenses 7,230 6,931 10,860 11,327
Other expenses 7,596 6,406 14,686 12,640
Gross contribution 999,372 960,732 2,010,889 1,926,680
Operating Segments | Conferences        
Segment Reporting [Line Items]        
Revenues 244,157 211,407 322,482 284,004
Personnel expenses 19,227 18,881 37,258 36,626
Product and content delivery expenses 73,645 65,197 100,401 89,368
Other expenses 6,063 5,941 9,192 9,240
Gross contribution 145,222 121,388 175,631 148,770
Operating Segments | Consulting        
Segment Reporting [Line Items]        
Revenues 141,916 155,594 261,045 295,300
Personnel expenses 80,825 86,511 156,441 165,603
Product and content delivery expenses 3,826 4,052 6,765 7,314
Other expenses 3,495 3,476 7,264 7,436
Gross contribution $ 53,770 61,555 90,575 114,947
Operating Segments | Other        
Segment Reporting [Line Items]        
Revenues   55,948 19,392 122,206
Personnel expenses   10,089 2,210 20,460
Product and content delivery expenses   31,367 9,475 68,148
Other expenses   549 130 1,080
Gross contribution   $ 13,943 $ 7,577 $ 32,518