SEGMENT INFORMATION - Reconciliation of Adjusted EBITDA to Operating Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Operating Income (Loss) from Continuing Operations Before Income Taxes [Abstract]
Operating income	$ 335,059	$ 253,268	$ 648,097	$ 503,378
Share-based compensation expense	12,226	18,079	33,849	25,927
Restructuring and other expense	9,691	12,388	13,278	89,317
Depreciation and amortization (including impairments)	648,527	706,790	1,291,232	1,315,514
Adjusted EBITDA	1,005,503	990,525	1,986,456	1,934,136
Cablevision
Operating Income (Loss) from Continuing Operations Before Income Taxes [Abstract]
Operating income	203,265	109,799	373,958	231,843
Share-based compensation expense	10,357	11,960	26,529	17,042
Restructuring and other expense	8,515	11,171	11,598	69,818
Depreciation and amortization (including impairments)	473,138	542,203	958,502	985,379
Adjusted EBITDA	695,275	675,133	1,370,587	1,304,082
Cequel Corp. [Member]
Operating Income (Loss) from Continuing Operations Before Income Taxes [Abstract]
Operating income	131,794	143,469	274,139	271,535
Share-based compensation expense	1,869	6,119	7,320	8,885
Restructuring and other expense	1,176	1,217	1,680	19,499
Depreciation and amortization (including impairments)	175,389	164,587	332,730	330,135
Adjusted EBITDA	$ 310,228	$ 315,392	$ 615,869	$ 630,054