One-time additional cash patronage distribution.

No definition available.

Name:	artna_AdditionalCashPatronageDistribution
Namespace Prefix:	artna_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Additional cash patronage distribution refund rate.

+ References

No definition available.

+ Details

Name:	artna_AdditionalCashPatronageDistributionRefundRate
Namespace Prefix:	artna_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Annual patronage refund rate

+ References

No definition available.

+ Details

Name:	artna_AnnualPatronageRefundRate
Namespace Prefix:	artna_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Rate of the fee that accompanies borrowing money under the debt instrument.

+ References

No definition available.

+ Details

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Namespace Prefix:	artna_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of financing agreements entered into by the entity.

+ References

No definition available.

+ Details

Name:	artna_NumberOfFinancingAgreements
Namespace Prefix:	artna_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount earned by the Company for patronage refunds.

+ References

No definition available.

+ Details

Name:	artna_PatronageRefundsEarned
Namespace Prefix:	artna_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

+ References

No definition available.

+ Details

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

- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of unused borrowing capacity under the long-term financing arrangement that is available to the entity as of the balance sheet date.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(b))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

- Definition

Weighted average interest rate of debt outstanding.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtWeightedAverageInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- References

No definition available.

+ Details

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

- Definition

Date the credit facility terminates, in CCYY-MM-DD format.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

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.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

- Details

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

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=artna_CitizensBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ConsolidatedEntitiesAxis=srt_ParentCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=artna_CobankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ConsolidatedEntitiesAxis=artna_ArtesianWaterMarylandMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=artna_DelawareDrinkingWaterStateRevolvingFundMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=artna_FinancingAgreementOneMember
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Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=artna_FinancingAgreementTwoMember
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Balance Type:
Period Type:

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DEBT, Lines of Credit (Details)		12 Months Ended
DEBT, Lines of Credit (Details)	Apr. 28, 2020 USD ($) Agreement	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Artesian Water [Member]
Line of Credit Facility [Abstract]
Weighted average interest rate paid on the lines of credit		1.82%
Citizens Bank [Member] \| Artesian Resources [Member]
Line of Credit Facility [Abstract]
Line of credit		$ 40,000,000
Available funds under this line of credit		$ 31,200,000
Expiration date of line of credit		May 31, 2021
Citizens Bank [Member] \| LIBOR [Member] \| Artesian Resources [Member]
Line of Credit Facility [Abstract]
Variable rate for credit facility		LIBOR
Interest rate		1.25%
CoBank [Member] \| Artesian Resources [Member]
Line of Credit Facility [Abstract]
Line of credit		$ 20,000,000
Available funds under this line of credit		$ 2,000,000.0
CoBank [Member] \| Artesian Water [Member]
Line of Credit Facility [Abstract]
Expiration date of line of credit		Jul. 30, 2021
Patronage refunds		$ 1,000,000.0	$ 900,000
Additional cash patronage distribution		$ 107,000
Additional cash patronage distribution, refund rate		0.10%
Annual patronage refund rate		1.00%	0.80%
CoBank [Member] \| Artesian Water Maryland [Member]
Line of Credit Facility [Abstract]
Line of credit		$ 10,000,000
CoBank [Member] \| LIBOR [Member] \| Artesian Water [Member]
Line of Credit Facility [Abstract]
Variable rate for credit facility		LIBOR
Interest rate		1.50%
Delaware Drinking Water State Revolving Fund [Member] \| Artesian Water [Member]
Line of Credit Facility [Abstract]
Number of financing agreements \| Agreement	3
Interest rate	0.60%
Fee rate	0.006
Delaware Drinking Water State Revolving Fund [Member] \| Financing Agreement One [Member] \| Artesian Water [Member]
Line of Credit Facility [Abstract]
Advance from financing agreements	$ 1,700,000
Delaware Drinking Water State Revolving Fund [Member] \| Financing Agreement Two [Member] \| Artesian Water [Member]
Line of Credit Facility [Abstract]
Advance from financing agreements	1,000,000.0
Delaware Drinking Water State Revolving Fund [Member] \| Financing Agreement Three [Member] \| Artesian Water [Member]
Line of Credit Facility [Abstract]
Advance from financing agreements	$ 1,300,000