ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Additional Information (Details) - USD ($)			3 Months Ended		9 Months Ended		12 Months Ended
	Jan. 02, 2019	Jan. 01, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 20, 2018	Apr. 18, 2017	Nov. 30, 2016	Apr. 10, 2015
ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES [Line Items]
Long-term Debt, Gross							$ 350,000,000
Debt Instrument, Fair Value Disclosure							$ 332,500,000
Revenue from Contract with Customer, Including Assessed Tax			$ 111,055,000	$ 110,730,000	$ 331,075,000	$ 325,557,000
Debt Instrument, Interest Rate, Stated Percentage							9.25%
Reassessed Estimated Fair Value of Award			26,400,000		26,400,000		$ 25,700,000
Related Party Transaction, Due from (to) Related Party, Total			2,100,000		2,100,000		208,000
Due to Related Parties			32,000		32,000		34,000
Operating Income (Loss)			32,467,000	32,101,000	79,130,000	64,229,000
Impairment and amartization expense			602,000		602,000
Operating Expenses, Total			78,588,000	78,629,000	251,945,000	261,328,000
Unearned Event Income					3,831,000	3,163,000	3,864,000
Selling, General and Administrative Expense, Total			36,125,000	36,530,000	114,080,000	112,413,000
Impairment of Long-Lived Assets Held-for-use			0	0	3,800,000	6,556,000
Operating Lease, Right-of-Use Asset			47,949,000		47,949,000		$ 0
Operating Lease, Liability			52,486,000		52,486,000
Accounting Standards Update 2016-02 [Member]
ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES [Line Items]
Lease, Practical Expedients, Package [true false]		true
Operating Lease, Right-of-Use Asset		$ 49,800,000
Operating Lease, Liability		54,100,000
Cumulative Effect on Retained Earnings, Net of Tax	$ 5,800,000
Deferred Rent Credit		$ 4,300,000
Barter Transactions [Member]
ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES [Line Items]
Revenue from Contract with Customer, Including Assessed Tax			574,000	713,000	1,700,000	2,200,000
Cost of Goods and Services Sold			424,000	673,000	1,300,000	2,100,000
Adjustment in Revenue				2,000,000
Marketing Services Fee Receivable			2,000,000		2,000,000
Selling, General and Administrative Expense, Total			150,000	40,000	451,000	121,000
Radio broadcasting and Reach Media segments [Member]
ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES [Line Items]
Sales Commissions and Fees			6,200,000	6,000,000	17,200,000	17,200,000
Fantastic Voyage [Member]
ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES [Line Items]
Operating Income Guarantee Through 2018 and 2019					1,700,000
Operating Income Guarantee Through 2020 and Thereafter					$ 1,750,000
Launch Support Assets [Member]
ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES [Line Items]
Finite Lived Intangible Assets Weighted Average Amortization Period					7 years 9 months 18 days		7 years 9 months 18 days
Finite Lived Intangible Assets Remaining Weighted Average Amortization Period					5 years 3 months 18 days		6 years 1 month 6 days
Additional Non-cash Launch Support for Carriage Initiation				976,000		976,000
Amortization of Intangible Assets			106,000	106,000	$ 317,000	317,000
Selling, General and Administrative Expense, Total			151,000	0	455,000	0
Detroit Market Radio Broadcasting Licenses [Member]
ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES [Line Items]
Impairment of Long-Lived Assets Held-for-use					3,800,000	3,800,000
Charlotte Market Radio Broadcasting Licenses [Member]
ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES [Line Items]
Impairment of Long-Lived Assets Held-for-use						2,700,000
Tom Joyner Foundation Inc [Member]
ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES [Line Items]
Reimbursement Expenditure Guarantee					$ 1,000,000
Percentage of Performance Bonus					50.00%
Tom Joyner Foundation Inc [Member] | Fantastic Voyage [Member]
ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES [Line Items]
Operating Income Guarantee					$ 250,000
Chief Executive Officer [Member]
ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES [Line Items]
Percentage Of Award Amount							4.00%
9.25% Senior Subordinated Notes due February 2020 [Member]
ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES [Line Items]
Long-term Debt, Gross			$ 0		$ 0		$ 2,000,000
Debt Instrument, Fair Value Disclosure							2,000,000
Debt Instrument, Interest Rate, Stated Percentage			9.25%		9.25%
Senior Subordinated Notes due March 2022 [Member]
ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES [Line Items]
Long-term Debt, Gross			$ 350,000,000		$ 350,000,000
Debt Instrument, Fair Value Disclosure			$ 343,000,000		$ 343,000,000
Debt Instrument, Interest Rate, Stated Percentage			7.375%		7.375%
MGM National Harbor Loan [Member]
ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES [Line Items]
Long-term Debt, Gross			$ 51,600,000		$ 51,600,000
Debt Instrument, Face Amount			50,000,000		50,000,000
Other Income					5,200,000	5,100,000
ABL Facility [Member]
ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES [Line Items]
Long-term Debt, Gross			0		0		0
Tv One Llc [Member]
ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES [Line Items]
Sales Commissions and Fees			$ 3,400,000	3,500,000	$ 10,900,000	10,400,000
Reach Media Inc [Member]
ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES [Line Items]
Noncontrolling Interest, Ownership Percentage by Parent			80.00%		80.00%
Reach Media Inc [Member] | Fantastic Voyage [Member]
ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES [Line Items]
Revenue from Contract with Customer, Including Assessed Tax					$ 10,400,000	9,300,000
Operating Income (Loss)					1,700,000	1,700,000
Operating Expenses, Total					8,700,000	7,600,000
Customer Advances [Member]
ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES [Line Items]
Revenue from Contract with Customer, Including Assessed Tax			$ 250,000	241,000	250,000	241,000
Unearned Event Income						4,100,000
Unearned Income [Member]
ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES [Line Items]
Revenue from Contract with Customer, Including Assessed Tax			2,300,000	2,000,000	2,300,000	2,000,000
2017 Credit Facility [Member]
ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES [Line Items]
Long-term Debt, Gross			321,500,000		321,500,000		323,900,000		$ 350,000,000
Debt Instrument, Fair Value Disclosure			310,500,000		310,500,000		305,800,000
Debt Instrument, Interest Rate, Stated Percentage									2.00%
Debt Instrument, Face Amount									$ 350,000,000
2018 Credit Facility [Member]
ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES [Line Items]
Long-term Debt, Gross			170,700,000		170,700,000		192,000,000
Debt Instrument, Fair Value Disclosure			$ 174,200,000		$ 174,200,000		$ 195,900,000
Debt Instrument, Interest Rate, Stated Percentage							12.875%
Debt Instrument, Face Amount								$ 192,000,000
Staffing And Recruiting Services [Member]
ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES [Line Items]
Related Party Transaction, Amounts of Transaction						25,000
Comcast Note [Member]
ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES [Line Items]
Long-term Debt, Gross							$ 11,900,000
Debt Instrument, Fair Value Disclosure							11,900,000
Debt Instrument, Interest Rate, Stated Percentage			10.47%		10.47%
Debt Instrument, Face Amount			$ 11,900,000		$ 11,900,000
Employment Agreement Award [Member]
ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES [Line Items]
Selling General And Administrative Expense (Benefit)			860,000	(6,600,000)	3,600,000	$ (3,700,000)
MGM National Harbor [Member]
ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES [Line Items]
Long-term Debt, Gross			51,600,000		51,600,000		50,100,000
Debt Instrument, Fair Value Disclosure			57,800,000		$ 57,800,000		$ 56,100,000
Investment Owned, at Cost										$ 35,000,000	$ 5,000,000
Other Income			$ 1,800,000	$ 1,700,000