XML 51 R40.htm IDEA: XBRL DOCUMENT
v3.21.1

REGULATORY ASSETS (Details) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2021 | Dec. 31, 2020
Regulatory Assets [Abstract] |  |
Cash received for bond issuance |  | $ 30,000
Amortization period of other regulatory expense [Abstract] |  |
Rate case studies | 5 years |
Goodwill | 50 years |
Deferred acquisition costs | 20 years |
Franchise costs | 80 years |
Regulatory assets net of amortization, comprise [Abstract] |  |
Regulatory assets, net | $ 6,368 | 6,473
Maximum [Member] |  |
Amortization period of other regulatory expense [Abstract] |  |
Debt related cost | 30 years |
Minimum [Member] |  |
Amortization period of other regulatory expense [Abstract] |  |
Debt related cost | 15 years |
Delaware [Member] |  |
Amortization period of other regulatory expense [Abstract] |  |
Regulatory rate proceedings | 2 years 6 months |
Maryland [Member] |  |
Amortization period of other regulatory expense [Abstract] |  |
Regulatory rate proceedings | 5 years |
Postretirement Benefit Obligation [Member] |  |
Regulatory assets net of amortization, comprise [Abstract] |  |
Regulatory assets, net | $ 367 | 370
Deferred Income Taxes [Member] |  |
Regulatory assets net of amortization, comprise [Abstract] |  |
Regulatory assets, net | 44 | 46
Debt Related Costs [Member] |  |
Regulatory assets net of amortization, comprise [Abstract] |  |
Regulatory assets, net | 5,145 | 5,233
Expense of Rate and Regulatory Proceedings [Member] |  |
Regulatory assets net of amortization, comprise [Abstract] |  |
Regulatory assets, net | 279 | 281
Goodwill [Member] |  |
Regulatory assets net of amortization, comprise [Abstract] |  |
Regulatory assets, net | 533 | 543
Deferred Acquisition and Franchise Costs [Member] |  |
Regulatory assets net of amortization, comprise [Abstract] |  |
Regulatory assets, net | $ 6,368 | $ 6,473

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

X
- References No definition available. + Details
Name: | artna_AmortizationPeriodOfOtherRegulatoryExpenseAbstract
Namespace Prefix: | artna_
Data Type: | xbrli:stringItemType
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
- References No definition available. + Details
Name: | artna_RegulatoryAssetsDisclosureAbstract
Namespace Prefix: | artna_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | artna_SummaryOfRegulatoryAssetsNetOfAmortizationCompriseAbstract
Namespace Prefix: | artna_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The cash inflow from amounts received from a long-term debt instrument secured by a first mortgage deed of trust, containing a pledge of real property. The lender has the highest claim on the property in case of default. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 14 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3255-108585 + Details
Name: | us-gaap_ProceedsFromIssuanceOfFirstMortgageBond
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
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: | duration

X
- Definition The amount for the individual regulatory asset as itemized in a table of regulatory assets as of the end of the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 340 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6499975&loc=d3e44250-110382 + Details
Name: | us-gaap_RegulatoryAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
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: |

X
- Details
Name: | us-gaap_RegulatoryAssetAxis=us-gaap_PostretirementBenefitCostsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryAssetAxis=us-gaap_DeferredIncomeTaxChargesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryAssetAxis=artna_DebtRelatedCostsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryAssetAxis=artna_ExpenseOfRateAndRegulatoryProceedingsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryAssetAxis=us-gaap_GoodwillMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryAssetAxis=artna_DeferredAcquisitionAndFranchiseCostsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |