CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Settlement loss related to pension plan	$ 606	$ 0

Amortization of Actuarial Gains (Losses) and Settlement Gains (Losses)

No definition available.

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