INCOME TAXES - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Impact from changes in tax rates, benefit		$ 1,046	$ 52,915	$ 12,896
Deferred income taxes		$ 14,931	(67,603)	(2,880,154)
Net operating loss carryforward			840,576
Alternative minimum tax credits			12,161
Research credits			17,824
Unrecognized tax benefits that would impact effective tax rate			1,720
Percentage of subsidiaries that file tax return		80.00%
Accounting Standards Update 2016-09
Business Acquisition [Line Items]
Noncash deferred tax benefit				2,332,677
Unrealized excess tax benefits recognized with the adoption of ASU 2016-09	$ 2,163
Noncash Deferred Tax Expense (Benefit)				(2,332,677)
New Jersey
Business Acquisition [Line Items]
Noncash deferred tax benefit			$ 52,915
Surtax			2.50%
Noncash Deferred Tax Expense (Benefit)			$ (52,915)
CSC Holdings
Business Acquisition [Line Items]
Impact from changes in tax rates, benefit		$ (6,532)	53,493	12,999
Deferred income taxes		$ (238,709)	(251,593)	(3,026,782)
CSC Holdings | Accounting Standards Update 2016-09
Business Acquisition [Line Items]
Noncash deferred tax benefit				2,731,324
Noncash Deferred Tax Expense (Benefit)				$ (2,731,324)
CSC Holdings | New Jersey
Business Acquisition [Line Items]
Noncash deferred tax benefit			53,493
Noncash Deferred Tax Expense (Benefit)			$ (53,493)