EQUITY PLANS, Valuation Assumptions (Details) - $ / shares	1 Months Ended	9 Months Ended
	Mar. 31, 2015	Sep. 30, 2015
Cablevision Systems Corporation 2015 Employee Stock Plan | Stock Options
Cablevision's Equity Plans [Abstract]
Expiration period from date of grant		10 years
Additional year due to death, expiration period		1 year
Cablevision Systems Corporation 2015 Employee Stock Plan | Stock Appreciation Rights (SARs)
Cablevision's Equity Plans [Abstract]
Expiration period from date of grant		10 years
Additional year due to death, expiration period		1 year
Cablevision Systems Corporation Employee Stock Plan | Stock Options
Cablevision's Equity Plans [Abstract]
Expiration period from date of grant	10 years
Vesting period	3 years
Annual vesting percentage (in hundredths)	33.33%
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
Dividend yield (in hundredths)		3.63%
Volatility (in hundredths)		39.98%
Grant date fair value (in dollars per share)		$ 5.45
CNYG Class A Common Stock | Cablevision Systems Corporation 2015 Employee Stock Plan
Cablevision's Equity Plans [Abstract]
Number of shares authorized		25,000,000