LEASES (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Finance Lease, Liability, Payments, Due Next Twelve Months	$ 26,935		$ 26,935
Finance Lease, Liability, Payments, Due Year Two	103,494		103,494
Finance Lease, Liability, Payments, Due Year Three	68,386		68,386
Finance Lease, Liability, Payments, Due Year Four	18,792		18,792
Finance Lease, Liability, Payments, Due Year Five	303		303
Finance Lease, Liability, Payments, Due after Year Five	1		1
Finance Lease, Liability, Payment, Due, Total	217,911		217,911
Finance Leases, Future Minimum Payments, Interest Included in Payments	10,823		10,823
Finance Leases, Future Minimum Payments, Present Value of Net Minimum Payments	207,088		207,088
Lessee, Operating Lease, Liability, Payments, Due Next Twelve Months	1,195		1,195
Lessee, Operating Lease, Liability, Payments, Due Year Two	55,071		55,071
Lessee, Operating Lease, Liability, Payments, Due Year Three	48,695		48,695
Lessee, Operating Lease, Liability, Payments, Due Year Four	44,681		44,681
Lessee, Operating Lease, Liability, Payments, Due Year Five	35,384		35,384
Lessee, Operating Lease, Liability, Payments, Due after Year Five	172,703		172,703
Lessee, Operating Lease, Liability, Payments, Due, Total	357,729		357,729
Operating Leases, Future Minimum Payments, Interest Included in Payments	78,236		78,236
Operating Leases, Future Minimum Payments, Present Value of Net Minimum Payments	279,493		279,493
Finance Lease, Right-of-Use Asset, Amortization	16,404	$ 8,898	40,716	$ 20,318
Finance Lease, Interest Expense	2,373	1,820	6,595	4,324
Finance Lease, Cost	18,777	10,718	47,311	24,642
Finance And Operating Lease, Lessee Expense	32,919	25,365	89,999	69,142
Operating Lease, Right-of-Use Asset, Amortization Expense	14,142	$ 14,647	42,688	$ 44,500
Right-of-use operating lease liability	244,317		244,317		$ 257,424
CSC Holdings
Right-of-use operating lease liability	$ 244,317		$ 244,317		$ 257,424