SEGMENT INFORMATION - Reconciliation of Adjusted EBITDA to Operating Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Operating Income (Loss) from Continuing Operations Before Income Taxes [Abstract]
Operating income	$ 505,558	$ 120,575	$ 1,153,655	$ 623,953
Share-based compensation expense	12,327	15,005	46,176	40,932
Restructuring and other expense	16,587	53,448	29,865	142,765
Depreciation and amortization (including impairments)	536,053	823,286	1,827,285	2,138,800
Adjusted EBITDA	1,070,525	1,012,314	3,056,981	2,946,450
Cablevision
Operating Income (Loss) from Continuing Operations Before Income Taxes [Abstract]
Operating income	340,455	(3,103)	714,413	228,740
Share-based compensation expense	9,038	11,555	35,567	28,597
Restructuring and other expense	14,122	35,364	25,720	105,182
Depreciation and amortization (including impairments)	378,549	656,122	1,337,051	1,641,501
Adjusted EBITDA	742,164	699,938	2,112,751	2,004,020
Cequel Corp. [Member]
Operating Income (Loss) from Continuing Operations Before Income Taxes [Abstract]
Operating income	165,103	123,678	439,242	395,213
Share-based compensation expense	3,289	3,450	10,609	12,335
Restructuring and other expense	2,465	18,084	4,145	37,583
Depreciation and amortization (including impairments)	157,504	167,164	490,234	497,299
Adjusted EBITDA	$ 328,361	$ 312,376	$ 944,230	$ 942,430