EQUITY PLANS, Valuation Assumptions (Details) (Cablevision Systems Corporation Employee Stock Plan, Stock Options, USD $)	3 Months Ended
	Mar. 31, 2015
Cablevision Systems Corporation Employee Stock Plan | Stock Options
Cablevision's Equity Plans [Abstract]
Vesting period	3 years
Annual vesting percentage (in hundredths)	33.33%
Expiration period from date of grant	10 years
Assumptions Used to Calculate the Fair Value of Stock Option Awards Granted [Abstract]
Risk-free interest rate (in hundredths)	1.82%
Expected life (in years)	8 years 0 months 0 days
Dividend yield (in hundredths)	3.63%
Volatility (in hundredths)	39.98%
Grant date fair value (in dollars per share)	$ 5.45