<?xml version="1.0" encoding="utf-8"?>
<FilingSummary xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <Version>2.4.0.6</Version>
  <ProcessingTime />
  <ReportFormat>Html</ReportFormat>
  <ContextCount>195</ContextCount>
  <ElementCount>192</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>42</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>5</UnitCount>
  <MyReports>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>0000 - Document - Document and Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.atni.com/role/DocumentAndEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
    </Report>
    <Report>
      <IsDefault>true</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>0010 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.atni.com/role/BalanceSheet</Role>
      <ShortName>CONDENSED CONSOLIDATED BALANCE SHEETS</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>0015 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.atni.com/role/BalanceSheetParenthetical</Role>
      <ShortName>CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>0020 - Statement - CONDENSED CONSOLIDATED INCOME STATEMENTS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.atni.com/role/StatementOfIncome</Role>
      <ShortName>CONDENSED CONSOLIDATED INCOME STATEMENTS</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>0025 - Statement - CONDENSED CONSOLIDATED INCOME STATEMENTS (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.atni.com/role/StatementOfIncomeParenthetical</Role>
      <ShortName>CONDENSED CONSOLIDATED INCOME STATEMENTS (Parenthetical)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>0030 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.atni.com/role/StatementOfComprehensiveIncome</Role>
      <ShortName>CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>0035 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.atni.com/role/StatementOfComprehensiveIncomeParenthetical</Role>
      <ShortName>CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>0040 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.atni.com/role/CashFlows</Role>
      <ShortName>CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>1010 - Disclosure - ORGANIZATION AND BUSINESS OPERATIONS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.atni.com/role/DisclosureOrganizationAndBusinessOperations</Role>
      <ShortName>ORGANIZATION AND BUSINESS OPERATIONS</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>1020 - Disclosure - BASIS OF PRESENTATION</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.atni.com/role/DisclosureBasisOfPresentation</Role>
      <ShortName>BASIS OF PRESENTATION</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>1030 - Disclosure - USE OF ESTIMATES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.atni.com/role/DisclosureUseOfEstimates</Role>
      <ShortName>USE OF ESTIMATES</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>1040 - Disclosure - ACQUISITIONS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.atni.com/role/DisclosureAcquisitions</Role>
      <ShortName>ACQUISITIONS</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>1050 - Disclosure - FAIR VALUE MEASUREMENTS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.atni.com/role/DisclosureFairValueMeasurements</Role>
      <ShortName>FAIR VALUE MEASUREMENTS</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>1060 - Disclosure - LONG-TERM DEBT</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.atni.com/role/DisclosureLongTermDebt</Role>
      <ShortName>LONG-TERM DEBT</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>1070 - Disclosure - DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.atni.com/role/DisclosureDerivativeInstrumentsAndHedgingActivities</Role>
      <ShortName>DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>1080 - Disclosure - RECONCILIATION OF TOTAL EQUITY</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.atni.com/role/DisclosureReconciliationOfTotalEquity</Role>
      <ShortName>RECONCILIATION OF TOTAL EQUITY</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>1090 - Disclosure - NET INCOME PER SHARE</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.atni.com/role/DisclosureNetIncomePerShare</Role>
      <ShortName>NET INCOME PER SHARE</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>1100 - Disclosure - SEGMENT REPORTING</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.atni.com/role/DisclosureSegmentReporting</Role>
      <ShortName>SEGMENT REPORTING</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>1110 - Disclosure - COMMITMENTS AND CONTINGENCIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.atni.com/role/DisclosureCommitmentsAndContingencies</Role>
      <ShortName>COMMITMENTS AND CONTINGENCIES</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>3010 - Disclosure - ORGANIZATION AND BUSINESS OPERATIONS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.atni.com/role/DisclosureScheduleOfPrincipalSubsidiariesOperatingActivitiesRevenueReportingSegmentsAndMarketsServed</Role>
      <ShortName>ORGANIZATION AND BUSINESS OPERATIONS</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>3040 - Disclosure - ACQUISITIONS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.atni.com/role/DisclosureAcquisitionsTables</Role>
      <ShortName>ACQUISITIONS (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>3050 - Disclosure - FAIR VALUE MEASUREMENTS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.atni.com/role/DisclosureFairValueMeasurementsTables</Role>
      <ShortName>FAIR VALUE MEASUREMENTS (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>3060 - Disclosure - LONG-TERM DEBT (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.atni.com/role/DisclosureLongTermDebtTables</Role>
      <ShortName>LONG-TERM DEBT (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>3070 - Disclosure - DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.atni.com/role/DisclosureDerivativeInstrumentsAndHedgingActivitiesTables</Role>
      <ShortName>DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>3080 - Disclosure - RECONCILIATION OF TOTAL EQUITY (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.atni.com/role/DisclosureReconciliationOfTotalEquityTables</Role>
      <ShortName>RECONCILIATION OF TOTAL EQUITY (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>3090 - Disclosure - NET INCOME PER SHARE (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.atni.com/role/DisclosureNetIncomePerShareTables</Role>
      <ShortName>NET INCOME PER SHARE (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>3100 - Disclosure - SEGMENT REPORTING (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.atni.com/role/DisclosureSegmentReportingTables</Role>
      <ShortName>SEGMENT REPORTING (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>4040 - Disclosure - ACQUISITIONS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.atni.com/role/DisclosureAcquisitionsDetails</Role>
      <ShortName>ACQUISITIONS (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>4050 - Disclosure - FAIR VALUE MEASUREMENTS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.atni.com/role/DisclosureFairValueMeasurementsDetails</Role>
      <ShortName>FAIR VALUE MEASUREMENTS (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>4060 - Disclosure - LONG-TERM DEBT (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.atni.com/role/DisclosureLongTermDebtDetails</Role>
      <ShortName>LONG-TERM DEBT (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>4070 - Disclosure - DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.atni.com/role/DisclosureDerivativeInstrumentsAndHedgingActivitiesDetails</Role>
      <ShortName>DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>4071 - Disclosure - DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES (Details 2)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.atni.com/role/DisclosureDerivativeInstrumentsAndHedgingActivitiesDetails2</Role>
      <ShortName>DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES (Details 2)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>4080 - Disclosure - RECONCILIATION OF TOTAL EQUITY (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.atni.com/role/DisclosureReconciliationOfTotalEquityDetails</Role>
      <ShortName>RECONCILIATION OF TOTAL EQUITY (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>4090 - Disclosure - NET INCOME PER SHARE (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.atni.com/role/DisclosureNetIncomePerShareDetails</Role>
      <ShortName>NET INCOME PER SHARE (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>4100 - Disclosure - SEGMENT REPORTING (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.atni.com/role/DisclosureSegmentReportingDetails</Role>
      <ShortName>SEGMENT REPORTING (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>4110 - Disclosure - COMMITMENTS AND CONTINGENCIES (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.atni.com/role/DisclosureCommitmentsAndContingenciesDetails</Role>
      <ShortName>COMMITMENTS AND CONTINGENCIES (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <Logs>
    <Log type="Info">'Monetary' elements on report '4060 - Disclosure - LONG-TERM DEBT (Details)' had a mix of different decimal attribute values.</Log>
    <Log type="Info">'Monetary' elements on report '4070 - Disclosure - DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES (Details)' had a mix of different decimal attribute values.</Log>
    <Log type="Info">'Monetary' elements on report '4071 - Disclosure - DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES (Details 2)' had a mix of different decimal attribute values.</Log>
    <Log type="Info">'Shares' elements on report '4090 - Disclosure - NET INCOME PER SHARE (Details)' had a mix of different decimal attribute values.</Log>
    <Log type="Info">Process Flow-Through: 0010 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS</Log>
    <Log type="Info">	Process Flow-Through: Removing column 'Jun. 30, 2011'</Log>
    <Log type="Info">	Process Flow-Through: Removing column 'Dec. 31, 2010'</Log>
    <Log type="Info">Process Flow-Through: 0015 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical)</Log>
    <Log type="Info">Process Flow-Through: 0020 - Statement - CONDENSED CONSOLIDATED INCOME STATEMENTS</Log>
    <Log type="Info">Process Flow-Through: 0025 - Statement - CONDENSED CONSOLIDATED INCOME STATEMENTS (Parenthetical)</Log>
    <Log type="Info">Process Flow-Through: 0030 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME</Log>
    <Log type="Info">	Process Flow-Through: Removing column '3 Months Ended
Jun. 30, 2012'</Log>
    <Log type="Info">	Process Flow-Through: Removing column '3 Months Ended
Jun. 30, 2011'</Log>
    <Log type="Info">Process Flow-Through: 0035 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical)</Log>
    <Log type="Info">Process Flow-Through: 0040 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS</Log>
  </Logs>
  <InputFiles>
    <File>atni-20120630.xml</File>
    <File>atni-20120630.xsd</File>
    <File>atni-20120630_cal.xml</File>
    <File>atni-20120630_def.xml</File>
    <File>atni-20120630_lab.xml</File>
    <File>atni-20120630_pre.xml</File>
  </InputFiles>
  <SupplementalFiles />
  <BaseTaxonomies />
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
