BENEFIT PLANS, Defined Benefit Plans (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Other pre-tax changes in plan assets and benefit obligations recognized in other comprehensive loss (income) [Abstract]
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, Net of Tax	$ 4,051		$ 12,858		$ 9,884
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), Net of Tax	(1,355)		(927)		(589)
Settlement loss included in net periodic benefit cost	3,155		0		0
Changes in plan assets and benefit obligations, net of taxes	(459)		11,931		9,295
Defined benefit plan, accumulated benefit obligation	430,846		433,916
Net funded status relating to defined benefit plans [Abstract]
Long-term defined benefit plan obligations	(120,644)		(162,812)
Cablevision Defined Benefit Plans [Member]
Change in benefit obligation [Roll Forward]
Projected benefit obligation at beginning of year	433,916		392,312
Service cost	774		45,346		39,789
Interest cost	18,040		14,128		14,570
Actuarial loss	9,006		5,282
Transfer of liabilities	0		(208)
Benefits paid	(30,890)		(22,944)
Projected benefit obligation at end of year	430,846		433,916		392,312
Change in plan assets [Roll Forward]
Fair value of plan assets at beginning of year	268,610		290,836
Actual return (loss) on plan assets, net	11,687		(8,694)
Employer contributions	54,269		9,620
Transfer of assets	0		(208)
Benefits paid	(30,890)		(22,944)
Fair value of plan assets at end of year	303,676		268,610		290,836
Unfunded status at end of year	(127,170)		(165,306)
Other pre-tax changes in plan assets and benefit obligations recognized in other comprehensive loss (income) [Abstract]
Unrecognized actuarial loss	6,866		21,842		16,732
Tax expense (benefit)	(2,815)		(8,984)		(6,848)
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, Net of Tax	4,051		12,858		9,884
Amortization of actuarial losses, net included in net periodic benefit cost	(2,364)		(1,645)		(1,067)
Tax expense (benefit)	969		677		437
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), Net of Tax	(1,395)		(968)		(630)
Settlement loss included in net periodic benefit cost	(5,348)		0		0
Tax expense (benefit)	2,193		0		0
Settlement loss included in net periodic benefit cost	3,155		0		0
Changes in plan assets and benefit obligations, net of taxes	(499)		11,890		9,254
Approximate amount expected to be recognized as a component of net periodic benefit cost from accumulated other comprehensive loss during the next fiscal year	2,239
Net funded status relating to defined benefit plans [Abstract]
Defined Benefit Plans	(127,170)		(165,306)
Less: Current portion	6,526		2,494
Long-term defined benefit plan obligations	(120,644)		(162,812)
Components of net periodic benefit cost [Abstract]
Service cost	774		45,346		39,789
Interest cost	18,040		14,128		14,570
Expected return on plan assets, net	(9,548)		(7,866)		(9,127)
Recognized actuarial loss (reclassified from accumulated other comprehensive loss)	2,364		1,645		752
Settlement loss (reclassified from accumulated other comprehensive loss)	5,348	[1]	0	[1]	315	[1]
Net periodic benefit cost	$ 16,978		$ 53,253		$ 46,299
CSC Supplemental Benefit Plan
Cablevision Defined Benefit Plans [Abstract]
Vesting percentage (in hundredths)	100.00%

[1] As a result of benefit payments to terminated or retired individuals exceeding the service and interest costs for the Pension Plan and the Excess Cash Balance Pension Plan during 2014, the Company recognized a non-cash settlement loss that represented the acceleration of the recognition of a portion of the previously unrecognized actuarial losses recorded in accumulated other comprehensive loss on the Company’s consolidated balance sheets relating to these plans.