SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of significant unobservable inputs of level 3 financial assets and liabilities (Details) $ in Thousands	Mar. 31, 2022 USD ($) $ / shares	Dec. 31, 2021 USD ($)
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value	$ 154,862	$ 167,744
Total assets measured at fair value	2,397,321	2,613,177
Mandatorily redeemable noncontrolling interests issued after November 5, 2003	4,502	4,506
Contingent earnout	22,464	0
Significant unobservable inputs (Level 3)
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total assets measured at fair value	1,271,055	1,250,735
Mandatorily redeemable noncontrolling interests issued after November 5, 2003	4,502	$ 4,506
Contingent earnout	22,464
Significant unobservable inputs (Level 3) | Market approach
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value	311,960
Fair value	32,833
Mandatorily redeemable noncontrolling interests issued after November 5, 2003	$ 4,502
Significant unobservable inputs (Level 3) | Market approach | Multiple of EBITDA
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Loans receivable at fair value, measurement input	5.00
Significant unobservable inputs (Level 3) | Market approach | Operating income multiple
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Mandatorily redeemable noncontrolling interesting, measurement input	6.0
Significant unobservable inputs (Level 3) | Market approach | Minimum | Multiple of EBITDA
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Equity securities, measurement input	3.75
Significant unobservable inputs (Level 3) | Market approach | Minimum | Multiple of PV-10
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Equity securities, measurement input	0.32
Significant unobservable inputs (Level 3) | Market approach | Minimum | Multiple of Sales
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Equity securities, measurement input	1.22
Significant unobservable inputs (Level 3) | Market approach | Minimum | Market price of related security
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Equity securities, measurement input | $ / shares	9.91
Significant unobservable inputs (Level 3) | Market approach | Maximum | Multiple of EBITDA
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Equity securities, measurement input	17.50
Significant unobservable inputs (Level 3) | Market approach | Maximum | Multiple of PV-10
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Equity securities, measurement input	0.70
Significant unobservable inputs (Level 3) | Market approach | Maximum | Multiple of Sales
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Equity securities, measurement input	1.25
Significant unobservable inputs (Level 3) | Market approach | Maximum | Market price of related security
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Equity securities, measurement input | $ / shares	64.51
Significant unobservable inputs (Level 3) | Market approach | Weighted Average | Multiple of EBITDA
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Equity securities, measurement input	6.85
Loans receivable at fair value, measurement input	5.00
Significant unobservable inputs (Level 3) | Market approach | Weighted Average | Multiple of PV-10
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Equity securities, measurement input	0.64
Significant unobservable inputs (Level 3) | Market approach | Weighted Average | Multiple of Sales
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Equity securities, measurement input	1.23
Significant unobservable inputs (Level 3) | Market approach | Weighted Average | Market price of related security
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Equity securities, measurement input | $ / shares	36.78
Significant unobservable inputs (Level 3) | Market approach | Weighted Average | Operating income multiple
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Mandatorily redeemable noncontrolling interesting, measurement input	6.0
Significant unobservable inputs (Level 3) | Discounted cash flow
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value	$ 72,290
Fair value	849,558
Contingent earnout	$ 22,464
Significant unobservable inputs (Level 3) | Discounted cash flow | Market interest rate
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Equity securities, measurement input	0.158
Significant unobservable inputs (Level 3) | Discounted cash flow | EBITDA volatility
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Contingent earnout, measurement input | $ / shares	0.75
Significant unobservable inputs (Level 3) | Discounted cash flow | Minimum | Market interest rate
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Loans receivable at fair value, measurement input	0.060
Significant unobservable inputs (Level 3) | Discounted cash flow | Maximum | Market interest rate
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Loans receivable at fair value, measurement input	0.400
Significant unobservable inputs (Level 3) | Discounted cash flow | Weighted Average | Market interest rate
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Equity securities, measurement input	0.158
Loans receivable at fair value, measurement input	0.262
Significant unobservable inputs (Level 3) | Discounted cash flow | Weighted Average | EBITDA volatility
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Contingent earnout, measurement input | $ / shares	0.75
Significant unobservable inputs (Level 3) | Option pricing model
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value	$ 4,414
Significant unobservable inputs (Level 3) | Option pricing model | Minimum | Annualized volatility
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Equity securities, measurement input	0.300
Significant unobservable inputs (Level 3) | Option pricing model | Maximum | Annualized volatility
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Equity securities, measurement input	4.840
Significant unobservable inputs (Level 3) | Option pricing model | Weighted Average | Annualized volatility
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Equity securities, measurement input	0.820