CONDENSED CONSOLIDATED INCOME STATEMENTS (Parenthetical) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
CONDENSED CONSOLIDATED INCOME STATEMENTS
Net loss (income) attributable to non-controlling interests, tax	$ 0.7	$ 0.6	$ 1.8	$ 1.4

This element represents the tax effect on the portion of income (loss) attributable to the non-controlling interest.

No definition available.

Name:	atni_NetIncomeAttributableToNoncontrollingInterestsTax
Namespace Prefix:	atni_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration