FAIR VALUE MEASUREMENTS - Fair value measurements on recurring and nonrecurring valuation techniques (Details)	6 Months Ended	12 Months Ended
	Jun. 30, 2024	Dec. 31, 2023
Discount Rate | Employment Agreement Award
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Significant Unobservable Input Value(a)	13.00%	10.00%
Discount Rate | Redeemable Non-controlling Interests
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Significant Unobservable Input Value(a)		12.50%
Discount Rate | Minimum | Employment Agreement Award
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Significant Unobservable Input Value(a)	(2.10%)	(2.10%)
Discount Rate | Maximum | Employment Agreement Award
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Significant Unobservable Input Value(a)	2.50%	2.50%
Operating profit margin range | Minimum | Employment Agreement Award
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Significant Unobservable Input Value(a)	38.00%	35.00%
Operating profit margin range | Minimum | Redeemable Non-controlling Interests
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Significant Unobservable Input Value(a)		24.50%
Operating profit margin range | Maximum | Employment Agreement Award
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Significant Unobservable Input Value(a)	41.20%	42.30%
Operating profit margin range | Maximum | Redeemable Non-controlling Interests
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Significant Unobservable Input Value(a)		31.90%
Average recurring EBITDA multiple | Employment Agreement Award
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Significant Unobservable Input Value(a)	4.50%
Average recurring EBITDA multiple | Minimum | Employment Agreement Award
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Significant Unobservable Input Value(a)		6.30%
Average recurring EBITDA multiple | Maximum | Employment Agreement Award
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Significant Unobservable Input Value(a)		6.50%
Revenue growth rate range | Minimum | Redeemable Non-controlling Interests
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Significant Unobservable Input Value(a)		1.20%
Revenue growth rate range | Maximum | Redeemable Non-controlling Interests
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Significant Unobservable Input Value(a)		16.50%
Exit multiple | Redeemable Non-controlling Interests
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Significant Unobservable Input Value(a)		4.00%