SEGMENT INFORMATION - Capital Expenditures by Reportable Segment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information, Capital Expenditures [Abstract]
Capital expenditures	$ 334,527	$ 255,329	$ 832,824	$ 718,919
Cablevision
Segment Reporting Information, Capital Expenditures [Abstract]
Capital expenditures	217,326	180,287	554,483	505,852
Cequel Corp. [Member]
Segment Reporting Information, Capital Expenditures [Abstract]
Capital expenditures	$ 117,201	$ 75,042	$ 278,341	$ 213,067