BUSINESS COMBINATIONS - Preliminary purchase price allocations (Details) - USD ($) $ in Thousands			9 Months Ended	11 Months Ended	12 Months Ended
	Apr. 20, 2021	Mar. 09, 2021	Sep. 30, 2021	Sep. 30, 2021	Dec. 31, 2020	Nov. 09, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Goodwill			$ 81,630	$ 81,630	$ 62,215		$ 43,920
Goodwill			(164)		$ (28)
2021 Urban One Exchange
Business Acquisition [Line Items]
Net property and equipment	$ 2,254
Radio broadcasting licenses	23,233
Total intangible assets	23,233
Total assets	$ 25,487
2021 Urban One Exchange | Minimum
Business Acquisition [Line Items]
Useful Lives in Years	0 years
2021 Urban One Exchange | Maximum
Business Acquisition [Line Items]
Useful Lives in Years	40 years
Podcorn
Business Acquisition [Line Items]
Cash		$ 702	702	702
Cash		0
Prepaid expenses, deposits and other		18	18	18
Prepaid expenses, deposits and other		0
Other assets, net of accumulated amortization		2,545	2,545	2,545
Other assets, net of accumulated amortization		0
Goodwill		19,579	19,611	19,611
Goodwill		32
Deferred tax asset		72	72	72
Deferred tax asset		0
Net working capital		95	63	63
Net working capital		(32)
Preliminary fair value of net assets acquired		23,011	23,011	23,011
Preliminary fair value of net assets acquired		$ 0
QL Gaming Group
Business Acquisition [Line Items]
Net property and equipment			8	8		$ 8
Net property and equipment				0
Other assets, net of accumulated amortization			14,608	14,608		14,608
Other assets, net of accumulated amortization				0
Goodwill			18,127	18,127		18,323
Goodwill				(196)
Total intangible and other assets			32,735	32,735		32,931
Total intangible and other assets				(196)
Deferred tax liabilities			(1,152)	(1,152)		(1,348)
Deferred tax liabilities				(196)
Net working capital			12	12		12
Net working capital				0
Preliminary fair value of net assets acquired			$ 31,603	31,603		$ 31,603
Preliminary fair value of net assets acquired				$ 0