ACQUISITIONS AND DISPOSITIONS - Additional Information (Details) - USD ($)		1 Months Ended		6 Months Ended
	Aug. 08, 2018	May 02, 2017	Jan. 30, 2017	Jun. 30, 2017	Aug. 09, 2018
ACQUISITIONS AND DISPOSITIONS
Proceeds from Divestiture of Businesses			$ 25,000,000
Sale Leaseback Transaction, Net Proceeds, Investing Activities		$ 25,000,000
Sale And Leaseback Transaction Gain		$ 22,500,000
Sale and Leaseback Transaction, Gain (Loss), Net				$ 14,400,000
Sale Leaseback Transaction, Deferred Gain, Net				$ 8,100,000
Business Acquisition Purchase Price Allocation Indefinite Live Intangible Assets Land And Land Improvements					$ 1,100,000
Business Acquisition Purchase Price Allocation Indefinite Live Intangible Assets Towers					512,000
Proceeds from Property Plant and Equipment Received in Cash	$ 12,200,000
Red Zebra Broadcasting [Member]
ACQUISITIONS AND DISPOSITIONS
Business Acquisition Purchase Price Allocation Indefinite Lived Intangible Assets, Radio Broadcasting Licenses					2,000,000
Business Acquisition Purchase Price Allocation Indefinite Lived Intangible Assets Including Goodwill					91,000
Business Acquisition Purchase Price Allocation Indefinite Live Intangible Assets Advertiser Agreements					206,000
Business Acquisition Purchase Price Allocation Indefinite Live Intangible Assets Other Property And Equipment					$ 254,000
Detroit radio station [Member]
ACQUISITIONS AND DISPOSITIONS
Proceeds from Sale of Property Held-for-sale	$ 12,700,000