COMMITMENTS AND CONTINGENCIES - Changes in the Rules on Television Ownership (Details) $ in Thousands		3 Months Ended								12 Months Ended
	Jul. 29, 2016	Dec. 31, 2017 USD ($) station	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2017 USD ($) station	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 06, 2016 station
Loss Contingencies [Line Items]
Loss contingency period for ongoing compliance monitoring	36 months
Revenue | $		$ 734,002	$ 670,891	$ 679,290	$ 649,935	$ 797,691	$ 693,835	$ 666,534	$ 578,889	$ 2,734,118	$ 2,736,949	$ 2,219,136
FCC nation ownership cap, % of domestic households reached													39.00%
Number of television stations owned		191								191
LMA
Loss Contingencies [Line Items]
Number of separately owned television stations having programming agreement										2
Number of stations that programs substantial portions of the broadcast day and sells advertising time to programming segments										1
JSA
Loss Contingencies [Line Items]
Revenue | $										$ 63,200	$ 58,600	$ 46,800
FCC Consent Decree Settlement
Loss Contingencies [Line Items]
Number of television stations owned													34
Loss contingency, % of domestic households reached, UHR discount applied													25.00%