FAIR VALUE MEASUREMENT (Tables)

12 Months Ended

Dec. 31, 2019

Fair Value Disclosures [Abstract]

Assets and Liabilities Measured at Fair Value on a Recurring Basis

The following table presents for each of these hierarchy levels, the Company's financial assets and financial liabilities that are measured at fair value on a recurring basis:

	Fair Value Hierarchy	December 31, 2019		December 31, 2018
Assets:
Money market funds	Level I	$	563,704	$	91,852
Investment securities pledged as collateral	Level I	1,931,697		1,462,626
Prepaid forward contracts	Level II	25,207		109,344
Interest rate swap contracts	Level II	—		1,975
Liabilities:
Prepaid forward contracts	Level II	94,795		—
Interest rate swap contracts	Level II	161,340		132,978
Contingent consideration related to 2017 and 2018 acquisitions	Level III	7,250		6,195

Schedule of Carrying Values and Estimated Fair Values of Debt Instruments

The carrying values, estimated fair values, and classification under the fair value hierarchy of the Company's financial instruments, excluding those that are carried at fair value in the accompanying consolidated balance sheets, are summarized as follows:

		December 31, 2019				December 31, 2018
	Fair Value Hierarchy	Carrying Amount (a)		Estimated Fair Value		Carrying Amount (a)		Estimated Fair Value
CSC Holdings debt instruments:
Credit facility debt	Level II	$	7,148,287	$	7,190,438	$	5,915,559	$	5,972,500
Collateralized indebtedness	Level II	1,585,088		1,611,095		1,406,182		1,374,203
Senior guaranteed notes	Level II	7,602,456		8,220,518		5,847,758		5,646,468
Senior notes	Level II	7,874,040		8,728,870		8,416,610		8,972,722
Notes payable and supply chain financing	Level II	140,994		141,713		106,108		105,836
Cablevision debt instruments:
Senior notes	Level II	—		—		1,095,193		1,163,843
		$	24,350,865	$	25,892,634	$	22,787,410	$	23,235,572

(a)Amounts are net of unamortized deferred financing costs and discounts/premiums.