CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Parenthetical) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS
Noncontrolling interest income tax expense (benefit)	$ 0.3	$ 0.6	$ 0.7	$ 1.0

Amount of current income tax expense (benefit) reported by noncontrolling interests.

No definition available.

Name:	atni_NoncontrollingInterestIncomeTaxExpenseBenefit
Namespace Prefix:	atni_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration