CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net loss	$ 33,739	$ (192,434)	$ (193,214)	$ (748,561)
Defined benefit pension plans:
Unrecognized actuarial gain (loss)	9,602	(4,056)	13,794	(8,389)
Applicable income taxes	2,592	(1,622)	3,723	(3,356)
Unrecognized gain (loss) arising during period, net of income taxes	7,010	(2,434)	10,071	(5,033)
Settlement loss included in other expense, net	65	1,014	929	1,403
Applicable income taxes	(18)	(406)	(252)	(561)
Settlement loss included in other expense, net, net of income taxes	47	608	677	842
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss), before Reclassification and Tax	437	0	1,351	0
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax	(27)	0	(365)	0
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	410	0	986	0
Other comprehensive gain (loss)	7,467	(1,826)	11,734	(6,108)
Comprehensive income (loss)	41,206	(194,260)	(181,480)	(754,669)
Comprehensive income attributable to noncontrolling interests	(1,186)	(135)	(1,039)	(737)
Comprehensive income (loss) attributable to Altice USA, Inc. stockholders	40,020	(194,395)	(182,519)	(755,406)
Customer Relationships [Member]
Defined benefit pension plans:
Settlement loss included in other expense, net	0	0	0	(3,195)
Applicable income taxes	0	0	0	1,278
Settlement loss included in other expense, net, net of income taxes	$ 0	$ 0	$ 0	$ (1,917)