AFFILIATE AND RELATED PARTY TRANSACTIONS - Revenue and Related Charges (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Related Party Transaction [Line Items]
Revenue	$ 3,974	$ 2,575	$ 1,100
Operating expenses:
Programming and other direct costs	(11,580)	(7,261)	(4,176)
Other operating expenses, net	(8,355)	(16,307)	(33,140)
Operating expenses, net	(19,935)	(23,568)	(37,316)
Interest expense	0	(600)	(90,405)
Interest Income, Related Party	0
Loss on extinguishment of debt and write-off of deferred financing costs		0	(513,723)
Net charges	(15,961)	(21,444)	(640,344)
Capital Expenditures	12,167	14,951	22,012
Related party, loss on extinguishment of debt			(513,723)
CSC Holdings
Operating expenses:
Net charges	$ (15,961)	(19,164)	(29,720)
Altice USA
Operating expenses:
Interest expense		(2,429)	(96,901)
Other income. net		149
New CSC Holdings Notes
Operating expenses:
Interest expense		(600)
Interest Income, Related Party		$ 2,429	$ 6,496