No definition available.

Name:	atni_MobilityFundLineItems
Namespace Prefix:	atni_
Data Type:	xbrli:stringItemType
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Represents the amount of Mobility Fund support approved by Federal Communications Commission (FCC).

No definition available.

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

Amount of Mobility Funds received by the entity since inception of the grant.

No definition available.

Name:	atni_MobilityFundsReceived
Namespace Prefix:	atni_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Represents the number of new funds created by Federal Communications Commission (FCC).

No definition available.

Name:	atni_NumberOfNewFundsCreatedByCommunicationsCommission
Namespace Prefix:	atni_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

Represents the period over which a portion of the Mobility Funds is used to offset the costs of supporting the networks.

No definition available.

Name:	atni_PeriodOverWhichMobilityFundUsedToOffsetCostsOfSupportingTheNetworks
Namespace Prefix:	atni_
Data Type:	xbrli:durationItemType
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Period Type:	duration

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

No definition available.

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_LetterOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	atni_TypeOfMobilityFundAxis=atni_WholesaleMobilityFundsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

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Data Type:	na
Balance Type:
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GOVERNMENT GRANTS (Details) $ in Millions	1 Months Ended	6 Months Ended
GOVERNMENT GRANTS (Details) $ in Millions	Aug. 31, 2013 USD ($)	Jun. 30, 2015 USD ($) item	Dec. 31, 2014 USD ($)
MOBILITY FUND GRANTS
Number of new funds created by FCC \| item		2
Period over which a portion of the Mobility Funds is used to offset the costs of supporting the networks		5 years
Letter of credit sub-facility
MOBILITY FUND GRANTS
Letters of credit posted to USAC		$ 10.6	$ 10.6
Wholesale Mobility Funds
MOBILITY FUND GRANTS
Mobility Funds approved by FCC	$ 21.7
Wholesale Mobility Funds \| U.S. Wireless
MOBILITY FUND GRANTS
Mobility Funds received		8.1
Wholesale Mobility Funds \| U.S. Wireless \| Property, Plant and Equipment [Member]
MOBILITY FUND GRANTS
Mobility Funds received		2.0
Wholesale Mobility Funds \| U.S. Wireless \| Other current liabilities
MOBILITY FUND GRANTS
Mobility Funds received		2.3
Wholesale Mobility Funds \| U.S. Wireless \| Other long-term liabilities
MOBILITY FUND GRANTS
Mobility Funds received		3.8
Wholesale Mobility Funds \| Letter of credit sub-facility
MOBILITY FUND GRANTS
Letters of credit posted to USAC		$ 10.6