RESTRUCTURING COSTS AND OTHER EXPENSE (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended		9 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Sep. 30, 2017	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Sep. 30, 2017
Restructuring Reserve [Roll Forward]
Accrual, beginning balance	$ 59,071				$ 123,100
Restructuring charges	14,667		$ 52,081		7,516		$ 141,078
Payments and other	(27,604)				(71,545)
Accrual, ending balance	46,134	$ 59,071			59,071
Transaction costs		1,920		$ 1,367	7,682	$ 1,687
Severance and Other Employee Related Costs
Restructuring Reserve [Roll Forward]
Accrual, beginning balance	51,964				113,474
Restructuring charges	5,841				4,182
Payments and other	(24,991)				(65,692)
Accrual, ending balance	32,814	51,964			51,964
Facility Realignment and Other Costs
Restructuring Reserve [Roll Forward]
Accrual, beginning balance	7,107				9,626
Restructuring charges	8,826				3,334
Payments and other	(2,613)				(5,853)
Accrual, ending balance	13,320	7,107			7,107
Cablevision
Restructuring Reserve [Roll Forward]
Cumulative restructuring costs	$ 327,521
Cequel
Restructuring Reserve [Roll Forward]
Cumulative restructuring costs		$ 71,162			$ 71,162