Segment Reporting - Schedule of Assets by Segments (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Segment Reporting Information [Line Items]
Total assets	$ 3,100,909	$ 2,777,363
Operating Segments
Segment Reporting Information [Line Items]
Total assets	2,349,079	2,306,001
Operating Segments | Corporate Finance
Segment Reporting Information [Line Items]
Total assets	927,543	925,082
Operating Segments | FLC
Segment Reporting Information [Line Items]
Total assets	445,602	412,803
Operating Segments | Economic Consulting
Segment Reporting Information [Line Items]
Total assets	554,978	553,217
Operating Segments | Technology
Segment Reporting Information [Line Items]
Total assets	206,376	200,396
Operating Segments | Strategic Communications
Segment Reporting Information [Line Items]
Total assets	214,580	214,503
Unallocated corporate assets
Segment Reporting Information [Line Items]
Total assets	$ 751,830	$ 471,362