ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Fair Value Measurements (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Liabilities subject to fair value measurement:
Contingent consideration		$ 780
Employment agreement award	$ 27,111	25,603
Total	27,111	26,383
Mezzanine equity subject to fair value measurement:
Redeemable noncontrolling interests	15,192	12,701
Fair Value, Inputs, Level 3 [Member]
Liabilities subject to fair value measurement:
Contingent consideration		780
Employment agreement award	27,111	25,603
Total	27,111	26,383
Mezzanine equity subject to fair value measurement:
Redeemable noncontrolling interests	$ 15,192	$ 12,701