INTANGIBLE ASSETS AND GOODWILL - Changes in carrying value of broadcasting licenses (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2019	Dec. 31, 2018
Changes in Intangible assets [Line Items]
Assets held for sale	$ (1,891)	$ (19,603)
Radio Broadcasting Licences [Member]
Changes in Intangible assets [Line Items]
Beginning of period balance	2,516,625	2,649,959
Impairment loss	0	(148,564)
Ending period balance	2,518,261	2,516,625
Radio Broadcasting Licences [Member] \| Cumulus Exchange [Member]
Changes in Intangible assets [Line Items]
Dispositions	(17,940)	(24,901)
Radio Broadcasting Licences [Member] \| 2019 Cumulus Exchange [Member]
Changes in Intangible assets [Line Items]
Beginning of period balance	2,516,625
Acquisition of radio stations	$ 19,576	40,131
Ending period balance		$ 2,516,625

Amount classified as assets attributable to disposal group held for sale or disposed of.

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