Segment Reporting - Revenues and Adjusted Segment Earnings before Interest, Taxes, Depreciation and Amortization for Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Segment Reporting Information [Line Items]
Revenues	$ 928,553	$ 806,706
Adjusted Segment EBITDA	150,091	112,746
Corporate Finance
Segment Reporting Information [Line Items]
Revenues	366,010	315,652
Adjusted Segment EBITDA	75,225	51,847
FLC
Segment Reporting Information [Line Items]
Revenues	176,074	157,739
Adjusted Segment EBITDA	33,709	21,784
Economic Consulting
Segment Reporting Information [Line Items]
Revenues	204,548	169,595
Adjusted Segment EBITDA	14,150	14,193
Technology
Segment Reporting Information [Line Items]
Revenues	100,713	90,618
Adjusted Segment EBITDA	14,581	15,366
Strategic Communications
Segment Reporting Information [Line Items]
Revenues	81,208	73,102
Adjusted Segment EBITDA	$ 12,426	$ 9,556