SEGMENT DATA - Segment Financial Information (Details) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2017 USD ($) market	Sep. 30, 2017 USD ($)	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 ($) market	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Segment Reporting [Abstract]
Number of markets | market		89								89
Intercompany loans		$ 159,800				$ 233,300				$ 159,800	$ 233,300
Intercompany interest expense										18,500	24,400	$ 23,100
Segment data
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
Depreciation of property and equipment										97,103	98,529	103,433
Amortization of definite-lived intangible assets and other assets										178,822	183,795	161,454
Amortization of program contract costs and net realizable value adjustments										115,523	127,880	124,619
General and administrative overhead expenses										113,253	73,556	64,246
Research and development										10,000	4,085	12,436
Operating income		357,581	$ 103,447	$ 118,849	$ 157,629	233,446	$ 153,994	$ 129,074	$ 86,339	737,506	602,853	422,736
Interest expense										212,315	211,143	191,447
Income from equity and cost method investments										(13,919)	1,735	964
Goodwill		2,124,033				1,990,746				2,124,033	1,990,746	1,931,093
Assets	[1]	6,784,470				5,963,168				6,784,470	5,963,168
Capital expenditures										83,812	94,465	91,421
Broadcast
Segment data
Goodwill		2,053,410				1,933,831				2,053,410	1,933,831	1,927,605
Other operating divisions segment
Segment data
Goodwill		70,623				56,915				70,623	56,915	3,488
Operating segments | Broadcast
Segment data
Revenue										2,490,528	2,530,510	2,118,021
Depreciation of property and equipment										88,751	91,573	99,616
Amortization of definite-lived intangible assets and other assets										155,640	155,479	152,049
Amortization of program contract costs and net realizable value adjustments										115,523	127,880	124,619
General and administrative overhead expenses										101,680	67,035	55,848
Research and development										0	0	0
Operating income										724,110	639,422	451,015
Interest expense										5,285	5,641	0
Income from equity and cost method investments										0	0	0
Goodwill		2,053,410				1,933,831				2,053,410	1,933,831
Assets		5,267,986				4,815,633				5,267,986	4,815,633
Capital expenditures										63,163	78,909
Operating segments | Other operating divisions segment
Segment data
Revenue										243,590	206,439	101,115
Depreciation of property and equipment										7,368	5,772	2,753
Amortization of definite-lived intangible assets and other assets										23,182	28,316	9,405
Amortization of program contract costs and net realizable value adjustments										0	0	0
General and administrative overhead expenses										1,009	2,459	2,952
Research and development										10,000	4,085	12,436
Operating income										24,943	(31,258)	(21,800)
Interest expense										1,835	6,371	4,955
Income from equity and cost method investments										(13,664)	1,735	964
Goodwill		70,623				56,915				70,623	56,915
Assets		769,919				866,845				769,919	866,845
Capital expenditures										5,546	8,084
Corporate
Segment data
Revenue										0	0	0
Depreciation of property and equipment										984	1,184	1,064
Amortization of definite-lived intangible assets and other assets										0	0	0
Amortization of program contract costs and net realizable value adjustments										0	0	0
General and administrative overhead expenses										10,564	4,062	5,446
Research and development										0	0	0
Operating income										(11,547)	(5,311)	(6,479)
Interest expense										205,195	199,131	186,492
Income from equity and cost method investments										(255)	0	$ 0
Goodwill		0				0				0	0
Assets		$ 746,565				$ 280,690				746,565	280,690
Capital expenditures										$ 15,103	$ 7,472

[1] Our consolidated total assets as of December 31, 2017 and 2016 include total assets of variable interest entities (VIEs) of $130.6 million and $142.3 million, respectively, which can only be used to settle the obligations of the VIEs. Our consolidated total liabilities as of December 31, 2017 and 2016 include total liabilities of the VIEs of $27.0 million and $40.9 million, respectively, for which the creditors of the VIEs have no recourse to us. See Note 1. Nature of Operations and Summary of Significant Accounting Policies.