XML 69 R58.htm IDEA: XBRL DOCUMENT
v3.25.3

REGULATORY ASSETS - Amortization Period of Other Regulatory Expense (Details) | 9 Months Ended
--- | ---
Sep. 30, 2025
REGULATORY ASSETS [Abstract] |
Deferred contract costs and other | 5 years
Amortization period | 5 years
Deferred costs affiliated interest agreement | 20 years
Goodwill | 50 years
Unrecovered reserve for depreciation (general plant assets) | 5 years
Minimum [Member] |
REGULATORY ASSETS [Abstract] |
Debt related costs | 15 years
Maximum [Member] |
REGULATORY ASSETS [Abstract] |
Debt related costs | 30 years
Delaware [Member] |
REGULATORY ASSETS [Abstract] |
Regulatory rate proceedings | 3 years
Deferred acquisition costs | 20 years
Delaware [Member] | Minimum [Member] |
REGULATORY ASSETS [Abstract] |
Deferred acquisition adjustments | 36 years
Delaware [Member] | Maximum [Member] |
REGULATORY ASSETS [Abstract] |
Deferred acquisition adjustments | 62 years
Maryland [Member] | Minimum [Member] |
REGULATORY ASSETS [Abstract] |
Deferred acquisition and franchise costs | 20 years
Maryland [Member] | Maximum [Member] |
REGULATORY ASSETS [Abstract] |
Deferred acquisition and franchise costs | 80 years

X
- Definition Period over which regulatory noncurrent asset for unrecovered reserve for depreciation are amortized. + References No definition available. + Details
Name: | artna_AmortizationPeriodForUnrecoveredReserveForDepreciation
Namespace Prefix: | artna_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Period over which regulatory noncurrent assets for goodwill is amortized on a straight-line basis. + References No definition available. + Details
Name: | artna_AmortizationPeriodGoodwill
Namespace Prefix: | artna_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents amortization period of debt related cost. + References No definition available. + Details
Name: | artna_AmortizationPeriodOfDebtRelatedCost
Namespace Prefix: | artna_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Period over which regulatory noncurrent asset for deferred acquisition adjustments are amortized. + References No definition available. + Details
Name: | artna_AmortizationPeriodOfDeferredAcquisitionAdjustments
Namespace Prefix: | artna_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Period over which regulatory noncurrent asset for deferred acquisition and franchise costs amortized. + References No definition available. + Details
Name: | artna_AmortizationPeriodOfDeferredAcquisitionAndFranchiseCosts
Namespace Prefix: | artna_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Period over which regulatory noncurrent asset for deferred acquisition costs amortized. + References No definition available. + Details
Name: | artna_AmortizationPeriodOfDeferredAcquisitionCosts
Namespace Prefix: | artna_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents amortization period of deferred contract costs and other. + References No definition available. + Details
Name: | artna_AmortizationPeriodOfDeferredContractCostsAndOther
Namespace Prefix: | artna_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amortization period of deferred costs affiliated interest agreement. + References No definition available. + Details
Name: | artna_AmortizationPeriodOfDeferredCostsAffiliatedInterestAgreement
Namespace Prefix: | artna_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Description of the amortization period for recovery of the individual regulatory noncurrent assets related to other expenses in a schedule of regulatory noncurrent assets. + References No definition available. + Details
Name: | artna_AmortizationPeriodOfRegulatoryRateProceedingsAndApplications
Namespace Prefix: | artna_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amortization period for the recovery of regulatory asset, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
Name: | us-gaap_RegulatoryAssetAmortizationPeriod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_RegulatoryAssetLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_StatementGeographicalAxis=stpr_DE
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_StatementGeographicalAxis=stpr_MD
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |