CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Parenthetical) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2026	Mar. 31, 2025
CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS
Non-controlling interest, net of tax (benefit) expense	$ 0.1	$ (0.2)

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