SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Fair Value Measurements (Details) - USD ($) $ in Thousands	Dec. 31, 2022		Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021
Liabilities subject to fair value measurement:
Employment agreement award	$ 26,300					$ 28,200
Total	26,283					28,193
Mezzanine equity subject to fair value measurement:
Redeemable noncontrolling interests	25,298	[1]				18,655
Assets subject to fair value measurement:
Available for sale securities	136,826		$ 115,600	$ 123,100	$ 123,000	112,600	$ 110,800	$ 106,400	$ 101,900
Cash equivalents - money market funds	39,798
Assets subject to fair value measurement value	176,624
Fair Value, Inputs, Level 1 [Member]
Assets subject to fair value measurement:
Cash equivalents - money market funds	39,798
Assets subject to fair value measurement value	39,798
Fair Value, Inputs, Level 3 [Member]
Liabilities subject to fair value measurement:
Total	26,283					28,193
Mezzanine equity subject to fair value measurement:
Redeemable noncontrolling interests	25,298	[1]				18,655
Assets subject to fair value measurement:
Available for sale securities	136,826					$ 112,600
Assets subject to fair value measurement value	$ 136,826

[1] The redeemable noncontrolling interest in Reach Media is measured at fair value using a discounted cash flow methodology. Significant inputs to the discounted cash flow analysis include revenue growth rates, future operating profit margins, discount rate and terminal growth rate.