BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES - Additional Information (Details) $ in Thousands		12 Months Ended
	Nov. 01, 2024 reporting_unit	Dec. 31, 2024 USD ($) reporting_unit practice_group	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Number of practice groups | practice_group		3
Revenue		$ 1,813,472	$ 1,591,194	$ 1,411,979
Notes receivable		$ 22,200
Maximum maturity period of investments		3 months
Allowance for doubtful accounts		$ 31,715	25,598	20,801	$ 16,158
Goodwill		2,331,461	865,180	819,917
Assets		4,470,883	2,043,592
Total stockholders' equity		$ 1,779,983	791,618	713,452	$ 704,548
Intangible assets amortization period		9 years 1 month 6 days
Number of reporting units | reporting_unit	6	6
Increase (decrease) in the fair value of contingent consideration, net		$ 6,993	2,743	2,435
Unsecured credit facility		2,000,000
Other income (expense), net
Summary Of Significant Accounting Policies [Line Items]
Increase (decrease) in the fair value of contingent consideration, net		$ (7,000)	(2,700)	(2,400)
Performance share units
Summary Of Significant Accounting Policies [Line Items]
Shares vesting term		3 years
Minimum
Summary Of Significant Accounting Policies [Line Items]
Shares vesting term		3 years
Intangible assets amortization period		3 years
Minimum | Capitalized software
Summary Of Significant Accounting Policies [Line Items]
Property and equipment useful life		3 years
Maximum
Summary Of Significant Accounting Policies [Line Items]
Shares vesting term		4 years
Intangible assets amortization period		15 years
Maximum | Capitalized software
Summary Of Significant Accounting Policies [Line Items]
Property and equipment useful life		5 years
Financial service
Summary Of Significant Accounting Policies [Line Items]
Revenue		$ 306,500	$ 259,600	$ 235,400