ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Fair Value Measurements (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Liabilities subject to fair value measurement:
Contingent consideration	$ 2,155	$ 2,831
Employment agreement award	26,374	25,660
Total	28,529	28,491
Mezzanine equity subject to fair value measurement:
Redeemable noncontrolling interests	9,247	10,232
Fair Value, Inputs, Level 3 [Member]
Liabilities subject to fair value measurement:
Contingent consideration	2,155	2,831
Employment agreement award	26,374	25,660
Total	28,529	28,491
Mezzanine equity subject to fair value measurement:
Redeemable noncontrolling interests	$ 9,247	$ 10,232