Amount of impairment loss resulting from write-down of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit to fair value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16373-109275

Name:	us-gaap_ImpairmentOfIntangibleAssetsIndefinitelivedExcludingGoodwill
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

PROPERTY, PLANT AND EQUIPMENT, INTANGIBLE ASSETS AND GOODWILL - Annual Impairment Test to Indefinite-lived Intangible Assets (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017 USD ($) market	Dec. 31, 2016 USD ($) market	Dec. 31, 2015 USD ($) market
Regulatory Assets [Line Items]
Period over which the Company forecasts revenue, expenses, and cash flows	10 years
Impairment charge \| $	$ 6.0	$ 0.7	$ 21.6
FCC licenses
Regulatory Assets [Line Items]
Number of markets	1	1
Billboard permits
Regulatory Assets [Line Items]
Number of markets			1