CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 1,331	$ 77,396	$ 86,410	$ (25,198)	$ 213,808	$ 33,739	$ (98,004)	$ (128,949)	$ 139,939	$ 20,594	$ 1,494,764
Defined benefit pension plans:
Unrecognized actuarial gain (loss)										830	(18,632)
Applicable income taxes										(220)	7,441
Unrecognized gain (loss) arising during period, net of income taxes									8,430	610	(11,191)
Applicable income taxes										0	0
Amortization of actuarial losses included in other expense, net of tax									65	0	0
Settlement loss included in other expense, net										1,268	1,845
Applicable income taxes										(342)	(738)
Settlement loss included in other expense, net, net of income taxes									1,202	926	1,107
Curtailment loss										0	(3,195)
Applicable income taxes										0	1,278
Curtailment loss, net of income taxes									0	0	(1,917)
Foreign currency translation adjustment										967	0
Applicable income taxes										(261)	0
Foreign currency translation adjustment, net of income taxes									(1,164)	706	0
Other comprehensive income (loss)									8,533	2,242	(12,001)
Comprehensive income									148,472	22,836	1,482,763
Comprehensive income attributable to noncontrolling interests										(1,761)	(1,587)
Comprehensive income attributable to Altice USA, Inc. stockholders									$ 147,469	$ 21,075	$ 1,481,176