v3.26.1
Operating Segments - Schedule of Information by Reportable Segment (Detail) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Mar. 31, 2026
Jun. 30, 2025
Mar. 31, 2025
Jun. 30, 2026
Jun. 30, 2025
Segment Reporting Information [Line Items]            
Total revenues $ 100,233   $ 111,659   $ 185,687 $ 201,535
Income (loss) from operations 3,398   6,956   (15,232) (80,635)
Selling, marketing, administrative and other expenses (50,411)   (55,118)   (102,449) (108,593)
Amortization of intangible assets (2,081)   (2,217)   (4,162) (4,434)
Goodwill impairment 0 $ (10,800) 0 $ (83,900) (10,800) (83,895)
Restructuring and related costs (2,066)   (491)   (4,212) (1,998)
Interest expense and other income     160      
Interest expense, credit loss expense, and other income (485)       (576)  
Interest expense, credit loss expense and other income, and loss on investments           (551)
Income (loss) before income taxes 2,913   7,116   (15,808) (81,186)
Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total revenues 100,233   111,659   185,687 201,535
Total segment expenses (42,277) [1]   (46,877) [2]   (79,296) [3] (83,250) [4]
Income (loss) from operations 57,956   64,782   106,391 118,285
Research Segment [Member]            
Segment Reporting Information [Line Items]            
Goodwill impairment         (10,800)  
Research Segment [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total revenues 77,451   83,715   149,183 157,187
Total segment expenses (25,700) [1]   (26,182) [2]   (52,310) (52,318) [4]
Income (loss) from operations 51,751   57,533   96,873 104,869
Consulting Segment [Member]            
Segment Reporting Information [Line Items]            
Goodwill impairment         0  
Consulting Segment [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total revenues 14,299   17,704   28,039 34,082
Total segment expenses (8,034) [1]   (10,156) [2]   (17,055) [3] (19,055) [4]
Income (loss) from operations 6,265   7,548   10,984 15,027
Events Segment [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total revenues 8,483   10,240   8,465 10,266
Total segment expenses (8,543) [1]   (10,539) [2]   (9,931) [3] (11,877) [4]
Income (loss) from operations (60)   (299)   (1,466) (1,611)
Research [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total revenues 71,708   77,926   138,598 146,340
Research [Member] | Research Segment [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total revenues 71,708   77,926   138,598 146,340
Research [Member] | Consulting Segment [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total revenues 0   0   0 0
Research [Member] | Events Segment [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total revenues 0   0   0 0
Consulting [Member]            
Segment Reporting Information [Line Items]            
Total revenues 20,042   23,493   38,624 44,929
Consulting [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total revenues 20,042   23,493   38,624 44,929
Consulting [Member] | Research Segment [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total revenues 5,743   5,789   10,585 10,847
Consulting [Member] | Consulting Segment [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total revenues 14,299   17,704   28,039 34,082
Consulting [Member] | Events Segment [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total revenues 0   0   0 0
Events [Member]            
Segment Reporting Information [Line Items]            
Total revenues 8,483   10,240   8,465 10,266
Events [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total revenues 8,483   10,240   8,465 10,266
Events [Member] | Research Segment [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total revenues 0   0   0 0
Events [Member] | Consulting Segment [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total revenues 0   0   0 0
Events [Member] | Events Segment [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total revenues 8,483   10,240   8,465 10,266
Compensation Benefits and Related Costs [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total segment expenses (30,165) [1]   (32,085) [2]   (61,634) [3] (62,843) [4]
Compensation Benefits and Related Costs [Member] | Research Segment [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total segment expenses (22,805) [1]   (23,414) [2]   (45,984) [3] (45,966) [4]
Compensation Benefits and Related Costs [Member] | Consulting Segment [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total segment expenses (6,064) [1]   (7,256) [2]   (13,019) [3] (14,163) [4]
Compensation Benefits and Related Costs [Member] | Events Segment [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total segment expenses (1,296) [1]   (1,415) [2]   (2,631) [3] (2,714) [4]
Direct Costs of Events [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total segment expenses (7,088) [1]   (8,973) [2]   (7,088) [3] (8,973) [4]
Direct Costs of Events [Member] | Research Segment [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total segment expenses 0 [1]   0 [2]   0 [3] 0 [4]
Direct Costs of Events [Member] | Consulting Segment [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total segment expenses 0 [1]   0 [2]   0 [3] 0 [4]
Direct Costs of Events [Member] | Events Segment [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total segment expenses (7,088) [1]   (8,973) [2]   (7,088) [3] (8,973) [4]
Professional Services [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total segment expenses (2,144) [1]   (2,743) [2]   (5,323) [3] (5,948) [4]
Professional Services [Member] | Research Segment [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total segment expenses (1,584) [1]   (1,657) [2]   (4,032) [3] (4,348) [4]
Professional Services [Member] | Consulting Segment [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total segment expenses (560) [1]   (1,010) [2]   (1,291) [3] (1,523) [4]
Professional Services [Member] | Events Segment [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total segment expenses 0 [1]   (76) [2]   0 [3] (77) [4]
Billable Expenses [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total segment expenses (1,401) [1]   (1,858) [2]   (2,714) [3] (3,298) [4]
Billable Expenses [Member] | Research Segment [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total segment expenses (104) [1]   (102) [2]   (177) [3] (185) [4]
Billable Expenses [Member] | Consulting Segment [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total segment expenses (1,297) [1]   (1,756) [2]   (2,537) [3] (3,113) [4]
Billable Expenses [Member] | Events Segment [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total segment expenses 0 [1]   0 [2]   0 [3] 0 [4]
Travel and Entertainment [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total segment expenses (993) [1]   (808) [2]   (1,540) [3] (1,314) [4]
Travel and Entertainment [Member] | Research Segment [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total segment expenses (763) [1]   (628) [2]   (1,209) [3] (1,017) [4]
Travel and Entertainment [Member] | Consulting Segment [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total segment expenses (96) [1]   (130) [2]   (171) [3] (242) [4]
Travel and Entertainment [Member] | Events Segment [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total segment expenses (134) [1]   (50) [2]   (160) [3] (55) [4]
Software [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total segment expenses (430) [1]   (371) [2]   (887) [3] (765) [4]
Software [Member] | Research Segment [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total segment expenses (421) [1]   (354) [2]   (855) [3] (731) [4]
Software [Member] | Consulting Segment [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total segment expenses (13) [1]   0 [2]   (23) [3] 0 [4]
Software [Member] | Events Segment [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total segment expenses 4 [1]   (17) [2]   (9) (34) [4]
Other Segment Expenses [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total segment expenses (56) [1],[5]   (39) [2],[6]   (110) [3],[7] (109) [4],[8]
Other Segment Expenses [Member] | Research Segment [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total segment expenses (23) [1],[5]   (27) [2],[6]   (53) [7] (71) [4],[8]
Other Segment Expenses [Member] | Consulting Segment [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total segment expenses (4) [1],[5]   (4) [2],[6]   (14) [3],[7] (14) [4],[8]
Other Segment Expenses [Member] | Events Segment [Member] | Operating Segments [Member]            
Segment Reporting Information [Line Items]            
Total segment expenses $ (29) [1],[5]   $ (8) [2],[6]   $ (43) [3],[7] $ (24) [4],[8]
[1] The significant expense categories and amounts align with the segment-level information that is regularly provided to the chief operating decision maker.
[2] The significant expense categories and amounts align with the segment-level information that is regularly provided to the chief operating decision maker.
[3] The significant expense categories and amounts align with the segment-level information that is regularly provided to the chief operating decision maker.
[4] The significant expense categories and amounts align with the segment-level information that is regularly provided to the chief operating decision maker.
[5] Other segment expenses for each reportable segment includes office supplies, maintenance, and training expenses.
[6] Other segment expenses for each reportable segment includes office supplies, maintenance, and training expenses.
[7] Other segment expenses for each reportable segment includes office supplies, maintenance, and training expenses.
[8] Other segment expenses for each reportable segment includes office supplies, maintenance, and training expenses.