NATURE OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Revenue Recognition, Effects of Adoption (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenues realized from station barter arrangements		$ 4,571
Expenses realized from barter arrangements		246
Operating income (loss)	$ 107,314	157,629
Net income	$ 43,123	$ 57,202
Basic earnings per share (USD per share)	$ 0.42	$ 0.62
Diluted earnings per share (USD per share)	$ 0.42	$ 0.61
Scenario, Previously Reported
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenues realized from station barter arrangements		$ 27,570
Expenses realized from barter arrangements		23,245
Operating income (loss)		$ 157,629
Basic earnings per share (USD per share)		$ 0.62
Diluted earnings per share (USD per share)		$ 0.61
Accounting Standards Update 2014-09 \| Restatement Adjustment
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenues realized from station barter arrangements		$ (22,999)
Expenses realized from barter arrangements		(22,999)
Operating income (loss)		0
Net income		$ 0
Basic earnings per share (USD per share)		$ 0.00
Diluted earnings per share (USD per share)		$ 0.00

Total expense recognized from advertising barter transactions for each income statement presented.

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-Name Accounting Standards Codification
-Topic 605
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Total revenue recognized from advertising barter transactions for each income statement presented.

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The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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