SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Fair value measurements on recurring and nonrecurring valuation techniques (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Discount rate | Employment agreement award
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Assumptions Measurement Rate	10.00%	10.50%
Discount rate | Redeemable Noncontrolling Interest [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Debt Securities, Available-for-Sale, Measurement Input	12.5	11.5
Discount rate | Minimum | Employment agreement award
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Assumptions Measurement Rate	(2.10%)	(4.10%)
Discount rate | Maximum | Employment agreement award
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Assumptions Measurement Rate	2.50%	4.20%
Operating profit margin range | Minimum | Employment agreement award
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Assumptions Measurement Rate	35.00%	33.70%
Operating profit margin range | Minimum | Redeemable Noncontrolling Interest [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Assumptions Measurement Rate	24.50%	25.80%
Operating profit margin range | Maximum | Employment agreement award
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Assumptions Measurement Rate	42.30%	46.60%
Operating profit margin range | Maximum | Redeemable Noncontrolling Interest [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Assumptions Measurement Rate	31.90%	29.80%
Revenue growth rate range | Minimum | Employment agreement award
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Assumptions Measurement Rate	(2.10%)	(4.10%)
Revenue growth rate range | Minimum | Redeemable Noncontrolling Interest [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Assumptions Measurement Rate	1.20%	0.20%
Revenue growth rate range | Maximum | Redeemable Noncontrolling Interest [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Assumptions Measurement Rate	16.50%	32.20%
Average recurring EBITDA multiple | Employment agreement award
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Assumptions Measurement Rate		6.60%
Average recurring EBITDA multiple | Minimum | Employment agreement award
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Assumptions Measurement Rate	6.30%
Average recurring EBITDA multiple | Maximum | Employment agreement award
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Assumptions Measurement Rate	6.50%
Exit Multiple | Employment agreement award
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Debt Securities, Available-for-Sale, Measurement Input	4.0