Name:	atni_CustomerReceivableCreditFacilityCurrentMaturities
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Period Type:	instant

Amount after unamortized (discount) premium and debt issuance costs of customer receivable credit facility classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer.

No definition available.

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

Percentage of the base rate before addition of LIBOR.

No definition available.

Name:	atni_DebtInstrumentBaseRateBeforeAdditionOfLondonInterbankOfferedRate
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The debt instrument covenant for net leverage ratio.

No definition available.

Name:	atni_DebtInstrumentCovenantNetLeverageRatio
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Period Type:	instant

The maximum consolidated net total leverage ratio under the debt instrument covenant.

No definition available.

Name:	atni_DebtInstrumentMaximumConsolidatedNetTotalLeverageRatio
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Data Type:	xbrli:pureItemType
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Period Type:	duration

The minimum consolidated fixed charge coverage ratio under the debt instrument covenant.

No definition available.

Name:	atni_DebtInstrumentMinimumConsolidatedFixedChargeCoverageRatio
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Data Type:	xbrli:pureItemType
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Trailing period of consolidated EBITDA under the debt instrument

No definition available.

Name:	atni_DebtInstrumentTrailingPeriodOfConsolidatedEBITD
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Period Type:	duration

The percentage of prepayment fee on loans.

No definition available.

Name:	atni_PrepaymentFeePercentage
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Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

No definition available.

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
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Data Type:	dtr-types:percentItemType
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Period Type:	duration

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

Name:	us-gaap_DebtInstrumentCarryingAmount
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Period Type:	instant

Face (par) amount of debt instrument at time of issuance.

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Name:	us-gaap_DebtInstrumentFaceAmount
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Period Type:	instant

Contractual interest rate for funds borrowed, under the debt agreement.

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Amount of the required periodic payments applied to principal.

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Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

Name:	us-gaap_DebtInstrumentTerm
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Indicates type of variable interest rate on debt instrument.

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Period Type:	duration

Amount, before accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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Name:	us-gaap_DeferredFinanceCostsGross
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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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-Paragraph 1
-Publisher FASB
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-Publisher FASB
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Name:	us-gaap_DeferredFinanceCostsNet
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Period Type:	instant

Fixed interest rate related to the interest rate derivative.

No definition available.

Name:	us-gaap_DerivativeFixedInterestRate
Namespace Prefix:	us-gaap_
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Balance Type:	na
Period Type:	instant

Nominal or face amount used to calculate payment on derivative.

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-Paragraph 1A
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Name:	us-gaap_DerivativeNotionalAmount
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Period Type:	instant

The number of derivative instruments of a particular group held by the entity.

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-Name Accounting Standards Codification
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Name:	us-gaap_DerivativeNumberOfInstrumentsHeld
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Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Period the derivative contract is outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

Name:	us-gaap_DerivativeTermOfContract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Fair value of asset after deduction of liability.

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-Topic 820
-SubTopic 10
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-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

Name:	us-gaap_FairValueNetAssetLiability
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

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Name:	us-gaap_GainsLossesOnExtinguishmentOfDebt
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

Name:	us-gaap_LineOfCredit
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Period Type:	instant

Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

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Name:	us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity
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Period Type:	instant

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
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Period Type:	instant

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

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-Topic 470
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Name:	us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

No definition available.

Name:	us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Amount, after deduction of unamortized premium (discount) and debt issuance cost, of long-term debt. Excludes lease obligation.

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-Topic 470
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-Name Accounting Standards Codification
-Section 50
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-Publisher FASB
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-Name Accounting Standards Codification
-Section S99
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Name:	us-gaap_LongTermDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- References

No definition available.

Name:	us-gaap_LongTermDebtAndCapitalLeaseObligationsIncludingCurrentMaturitiesAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Amount, after deduction of unamortized premium (discount) and debt issuance cost, of long-term debt classified as current. Excludes lease obligation.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
-SubTopic 10
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-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(20))
-Publisher FASB
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Name:	us-gaap_LongTermDebtCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount, after deduction of unamortized premium (discount) and debt issuance cost, of long-term debt classified as noncurrent. Excludes lease obligation.

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-Topic 210
-SubTopic 10
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-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-Publisher FASB
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Name:	us-gaap_LongTermDebtNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The cash inflow from a contractual arrangement with the lender, including letter of credit, standby letter of credit and revolving credit arrangements, under which borrowings can be made up to a specific amount at any point in time with maturities due beyond one year or the operating cycle, if longer.

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-Subparagraph (b)
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-URI https://asc.fasb.org/1943274/2147482740/230-10-45-14

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