BUSINESS COMBINATIONS - Additional Information (Details) $ in Thousands, shares in Millions			2 Months Ended	12 Months Ended
	Nov. 01, 2024 USD ($) shares	Jul. 01, 2023 client	Dec. 31, 2024 USD ($)	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Business Acquisition, Contingent Consideration [Line Items]
Cash consideration				$ 1,087,521	$ 53,110	$ 79,141
Goodwill			$ 2,331,461	2,331,461	865,180	819,917
Number of clients from acquiree | client		1,200
Annual aggregate revenue				$ 2,790,091	2,698,828
Client lists
Business Acquisition, Contingent Consideration [Line Items]
Weighted Average Useful Life (in years)				10 years
Other intangibles
Business Acquisition, Contingent Consideration [Line Items]
Weighted Average Useful Life (in years)				3 years
Benefits and Insurance Services
Business Acquisition, Contingent Consideration [Line Items]
Goodwill			330,229	$ 330,229	316,324	$ 312,392
Marcum LLP
Business Acquisition, Contingent Consideration [Line Items]
Revenues			108,900
Operating losses			57,100
Amortization of intangible assets			8,900
Cash consideration	$ 1,063,037
Common stock	$ 934,744
Equity interest issued or issuable (in shares) | shares	13.6
Amount of goodwill deductible for income tax purposes	$ 379,500
Goodwill	1,445,070
Deferred income taxes, net	3,427		3,400	3,400
Transaction and integration related costs				28,700
Total consideration transferred	1,997,781
Cash payment amount	1,142,400
Contingent purchase price assumed (current and non-current)	$ 24,232
Marcum LLP | Client lists
Business Acquisition, Contingent Consideration [Line Items]
Weighted Average Useful Life (in years)	10 years
Marcum LLP | Financial Services Practice Group
Business Acquisition, Contingent Consideration [Line Items]
Goodwill	$ 1,433,500
Marcum LLP | Benefits and Insurance Services
Business Acquisition, Contingent Consideration [Line Items]
Goodwill	$ 11,600
Other 2024 Acquisitions
Business Acquisition, Contingent Consideration [Line Items]
Common stock				2,400
Total consideration transferred				42,200
Cash payment amount				24,000
Contingent purchase price assumed (current and non-current)			$ 15,800	15,800
Annual aggregate revenue				$ 28,700
2023 Acquisitions
Business Acquisition, Contingent Consideration [Line Items]
Common stock					4,800
Total consideration transferred					90,000
Cash payment amount					53,000
Contingent purchase price assumed (current and non-current)					32,100
Annual aggregate revenue					$ 64,900