SUPPLEMENTAL CASH FLOW INFORMATION (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Non-Cash Investing and Financing Activities:
Conversion of notes payable to affiliates and related parties of $1,750,000 (together with accrued and unpaid interest and applicable premium) to common stock (See Note 11)	$ 0	$ 0	$ 2,264,252
Property and equipment accrued but unpaid	188,067	213,936	171,604
Leasehold improvements paid by landlord	0	350	3,998
Notes payable issued to vendor for the purchase of equipment and other assets	35,124	95,394	40,131
Right-of-Use Asset Obtained in Exchange for Finance Lease Liability	54,532	13,548	9,385
Deferred financing costs accrued but unpaid	8	1,005	0
Contingent consideration for acquisitions	1,555	6,195	32,233
Receivable related to the sale of an investment	0	4,015	0
Assumption of Debt from Parent	169,334	0	0
Supplemental Data:
Interest Paid, Excluding Capitalized Interest, Operating Activities	1,436,332	1,481,468	1,765,126
Income taxes paid, net	10,263	13,667	29,006
Noncash contribution from parent	19,697	0	0
CSC Holdings
Supplemental Data:
Interest Paid, Excluding Capitalized Interest, Operating Activities	1,350,756	1,163,942	1,174,003
Income taxes paid, net	$ 10,263	13,667	$ 352,316
Noncash contribution from parent		$ 151,455