Goodwill and Other Intangible Assets - Summary of Changes in Carrying Amount of Goodwill (Detail) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2025	Mar. 31, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Goodwill [Line Items]
Goodwill, Beginning Balance		$ 227,959		$ 227,959
Impairment	$ 0	(83,900)	$ 0	(83,895)	$ 0
Translation adjustments				3,312
Goodwill, Ending Balance	147,376			147,376
Research Segment [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance		219,814		219,814
Impairment				(83,895)
Translation adjustments				3,151
Goodwill, Ending Balance	139,070			139,070
Consulting Segment Member
Goodwill [Line Items]
Goodwill, Beginning Balance		$ 8,145		8,145
Impairment				0
Translation adjustments				161
Goodwill, Ending Balance	$ 8,306			$ 8,306