ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Fair value measured on recurring basis (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2021 USD ($)
Contingent Consideration [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	$ 780
Distribution	(1,060)
Change in fair value	280
The amount of total (losses)/income for the period included in earnings attributable to the change in unrealized losses/income relating to assets and liabilities still held at the reporting date	(280)
Employment Agreement Award [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	25,603
Change in fair value	1,508
Balance, end of period	27,111
The amount of total (losses)/income for the period included in earnings attributable to the change in unrealized losses/income relating to assets and liabilities still held at the reporting date	(1,508)
Redeemable Noncontrolling Interest [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	12,701
Net income attributable to redeemable noncontrolling interests	1,066
Change in fair value	1,425
Balance, end of period	$ 15,192