CONSOLIDATED INCOME STATEMENTS (Parentheticals) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
CONSOLIDATED INCOME STATEMENTS
Noncontrolling interest income tax expense (benefit)	$ 0.1	$ 0.5	$ 0.4	$ 0.4

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