CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Settlement loss (gain) related to pension plan	$ 1,845	$ 0

Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement Gains (Losses)

No definition available.

Name:	atus_OtherComprehensiveIncomeLossDefinedBenefitPlanSettlementGainsLosses
Namespace Prefix:	atus_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration