CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Parent [Member]	Retained Earnings [Member]	Treasury Stock [Member]	AOCI Attributable to Parent [Member]	Noncontrolling Interests	Additional Paid-in Capital [Member]	Common Class A Common Stock	Common Class B Common Stock
Beginning balance at Dec. 31, 2018	$ 3,680,236	$ 3,670,941	$ 251,830	$ 0	$ (11,783)	$ 9,295	$ 3,423,803	$ 4,961	$ 2,130
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss attributable to Altice USA, Inc. stockholders	(24,999)	(24,999)	(24,999)
Net loss attributable to noncontrolling interests	199					199
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Plan Amendments, Net Of Tax	(3,752)	(3,752)			(3,752)
Foreign currency translation adjustment, net of income taxes	(181)	(181)			(181)
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	13,790	13,790					13,790
Redeemable equity vested	1,364	1,364					1,364
Adjustments to Additional Paid in Capital, Increase in Carrying Amount of Redeemable Preferred Stock	(61,696)	(61,696)					(61,696)
Class A shares acquired through share repurchase program and retired	(600,001)	(600,001)					(599,707)	(294)
Conversion of Class B to Class A shares								242	(242)
Ending balance at Mar. 31, 2019	3,011,066	3,002,970	226,831	0	(8,212)	8,096	2,777,554	4,909	1,888
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders	1,000					1,000
Beginning balance at Dec. 31, 2019	2,279,262	2,269,964	390,766	(163,904)	(3,250)	9,298	2,039,918	4,572	1,862
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss attributable to Altice USA, Inc. stockholders	(858)	(858)	(858)
Net loss attributable to noncontrolling interests	680					680
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Plan Amendments, Net Of Tax	9,503	9,503			9,503
Foreign currency translation adjustment, net of income taxes	(424)	(424)			(424)
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	27,370	27,370					27,370
Redeemable equity vested	29,479	29,479					29,479
Adjustments to Additional Paid in Capital, Increase in Carrying Amount of Redeemable Preferred Stock	13,260	13,260					13,260
Class A shares acquired through share repurchase program and retired	(749,998)	(749,998)					(749,686)	(312)
Stock Issued During Period, Value, New Issues							2,495	1
Ending balance at Mar. 31, 2020	$ 1,590,415	$ 1,581,797	$ 389,908	(163,893)	$ (13,177)	$ 8,618	$ 1,362,836	$ 4,261	$ 1,862
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock Issued During Period, Value, Treasury Stock Reissued				$ 11