COMMITMENTS AND CONTINGENCIES - Network Affiliation Agreements (Details) $ in Thousands	1 Months Ended	3 Months Ended								12 Months Ended
	Feb. 28, 2017 USD ($) station	Dec. 31, 2016 USD ($) station	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($) station	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 06, 2016 station	Jul. 29, 2016 USD ($)
Loss Contingencies [Line Items]
Revenue | $		$ 797,691	$ 693,835	$ 666,534	$ 578,889	$ 611,790	$ 548,404	$ 554,167	$ 504,775		$ 2,736,949	$ 2,219,136	$ 1,976,558
FCC nation ownership cap, % of domestic households reached														39.00%
Number of television stations owned | station		173									173
LMA
Loss Contingencies [Line Items]
Number of separately owned television stations having programming agreement | station											2
Number of stations that programs substantial portions of the broadcast day and sells advertising time to programming segments | station											1
JSA
Loss Contingencies [Line Items]
Revenue | $											$ 58,600	$ 46,800
FCC Consent Decree Settlement
Loss Contingencies [Line Items]
Loss contingency accrual | $															$ 9,500
Loss contingency period for ongoing compliance monitoring											36 months
Number of television stations owned | station														28
Loss contingency, % of domestic households reached														38.00%
Loss contingency, % of domestic households reached, UHR discount applied														24.00%
Subsequent Event
Loss Contingencies [Line Items]
Number of stations assigned new channels | station	93
Total legislation funds to reimburse stations | $	$ 1,750,000
Scenario, Forecast | Subsequent Event
Loss Contingencies [Line Items]
Broadcast incentive auction proceeds | $										$ 313,000