Annual patronage refund rate

No definition available.

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

- Definition

Number of consecutive quarterly installments payable under the agreement.

+ References

No definition available.

+ Details

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

- Definition

Number of supplements in loan agreement.

+ References

No definition available.

+ Details

Name:	artna_NumberOfSupplements
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

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

+ Details

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

- Definition

Description of the frequency of periodic payments (monthly, quarterly, annual).

+ 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)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

+ Details

Name:	us-gaap_DebtInstrumentFrequencyOfPeriodicPayment
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

+ Details

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

- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(2))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

+ Details

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

- References

No definition available.

+ Details

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

- 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

Name:	us-gaap_LineOfCreditFacilityAbstract
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

+ Details

Name:	us-gaap_LineOfCreditFacilityExpirationDate1
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

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
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

+ Details

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

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(3)
-URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 4: 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))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- References

No definition available.

+ Details

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

- References

No definition available.

+ Details

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

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

+ Details

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

- Definition

Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-04.(a))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24072-122690

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6802200&loc=d3e1835-112601

+ Details

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

- Definition

Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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

- Definition

Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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

- Definition

Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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

- Definition

Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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

- Definition

Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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

- Definition

Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

+ Details

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

- Details

Name:	us-gaap_DebtInstrumentAxis=artna_PromissoryNoteMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_CreditFacilityAxis=artna_MasterLoanAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=artna_FirstSupplementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=artna_SecondSupplementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_DebtInstrumentAxis=artna_SeriesR596Due12312028Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=artna_SeriesS445Due12312033Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=artna_SeriesT424Due12202036Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=artna_SeriesUDue01312038Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=artna_SeriesVDue10312049Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_DebtInstrumentAxis=artna_StateRevolvingFundLoan448Due08012021Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=artna_StateRevolvingFundLoan357Due09012023Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=artna_StateRevolvingFundLoan364Due05012025Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=artna_StateRevolvingFundLoan341Due02012031Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=artna_StateRevolvingFundLoan340Due07012032Member
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:

DEBT (Details) $ in Thousands	12 Months Ended
DEBT (Details) $ in Thousands	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($) Supplement Installment	Aug. 08, 2018 USD ($)
Long-term debt consists of [Abstract]
Principal amount	$ 145,862	$ 117,587
Less: current maturities (principal amount)	1,706	1,725
Total long-term debt	144,156	115,862
Payments of principal amounts due during the next five years and thereafter [Abstract]
2020	1,706
2021	1,822
2022	1,544
2023	1,585
2024	1,520
Thereafter	137,685
Promissory Note [Member]
Long-term debt consists of [Abstract]
Principal amount	$ 11,648	$ 12,000
Artesian Water [Member]
Line of Credit Facility [Abstract]
Weighted average interest rate paid on the lines of credit	3.74%
Master Loan Agreement [Member]
Debt Instruments [Abstract]
Number of supplements \| Supplement		2
Face amount		$ 12,000
Interest rate, stated percentage			5.12%
Frequency of payment		quarterly
Number of quarterly installments \| Installment		80
Long-term debt consists of [Abstract]
Principal amount			$ 12,000
Master Loan Agreement [Member] \| First Installment [Member]
Debt Instruments [Abstract]
Maturity date	Mar. 30, 2019
Master Loan Agreement [Member] \| Second Installment [Member]
Debt Instruments [Abstract]
Maturity date	Dec. 30, 2038
First Mortgage Bonds [Member]
Long-term debt consists of [Abstract]
Principal amount	$ 128,400	$ 99,000
Payments of principal amounts due during the next five years and thereafter [Abstract]
2020	600
2021	600
2022	600
2023	600
2024	600
Thereafter	$ 125,400
First Mortgage Bonds [Member] \| Series R [Member]
Debt Instruments [Abstract]
Interest rate, stated percentage	5.96%
Maturity date	Dec. 31, 2028
Long-term debt consists of [Abstract]
Principal amount	$ 25,000	25,000
First Mortgage Bonds [Member] \| Series S [Member]
Debt Instruments [Abstract]
Interest rate, stated percentage	4.45%
Maturity date	Dec. 31, 2033
Long-term debt consists of [Abstract]
Principal amount	$ 8,400	9,000
First Mortgage Bonds [Member] \| Series T [Member]
Debt Instruments [Abstract]
Interest rate, stated percentage	4.24%
Maturity date	Dec. 20, 2036
Long-term debt consists of [Abstract]
Principal amount	$ 40,000	40,000
First Mortgage Bonds [Member] \| Series U [Member]
Debt Instruments [Abstract]
Interest rate, stated percentage	4.71%
Maturity date	Jan. 31, 2038
Long-term debt consists of [Abstract]
Principal amount	$ 25,000	25,000
First Mortgage Bonds [Member] \| Series V [Member]
Debt Instruments [Abstract]
Interest rate, stated percentage	4.42%
Maturity date	Oct. 31, 2049
Long-term debt consists of [Abstract]
Principal amount	$ 30,000	0
State Revolving Fund Loans [Member]
Long-term debt consists of [Abstract]
Principal amount	5,814	6,587
Payments of principal amounts due during the next five years and thereafter [Abstract]
2020	737
2021	832
2022	533
2023	552
2024	466
Thereafter	$ 2,694
State Revolving Fund Loans [Member] \| 4.48%, due 08/01/2021 [Member]
Debt Instruments [Abstract]
Interest rate, stated percentage	4.48%
Maturity date	Aug. 01, 2021
Long-term debt consists of [Abstract]
Principal amount	$ 622	912
State Revolving Fund Loans [Member] \| 3.57%, due 09/01/2023 [Member]
Debt Instruments [Abstract]
Interest rate, stated percentage	3.57%
Maturity date	Sep. 01, 2023
Long-term debt consists of [Abstract]
Principal amount	$ 385	473
State Revolving Fund Loans [Member] \| 3.64%, due 05/01/2025 [Member]
Debt Instruments [Abstract]
Interest rate, stated percentage	3.64%
Maturity date	May 01, 2025
Long-term debt consists of [Abstract]
Principal amount	$ 778	904
State Revolving Fund Loans [Member] \| 3.41%, due 02/01/2031 [Member]
Debt Instruments [Abstract]
Interest rate, stated percentage	3.41%
Maturity date	Feb. 01, 2031
Long-term debt consists of [Abstract]
Principal amount	$ 2,034	2,177
State Revolving Fund Loans [Member] \| 3.40%, due 07/01/2032 [Member]
Debt Instruments [Abstract]
Interest rate, stated percentage	3.40%
Maturity date	Jul. 01, 2032
Long-term debt consists of [Abstract]
Principal amount	$ 1,995	2,121
State Revolving Fund Loans [Member] \| Promissory Note [Member]
Payments of principal amounts due during the next five years and thereafter [Abstract]
2020	369
2021	390
2022	411
2023	433
2024	454
Thereafter	9,591
Citizens Bank [Member] \| Artesian Resources [Member]
Line of Credit Facility [Abstract]
Line of credit	40,000
Available funds under this line of credit	$ 40,000
Expiration date of line of credit	May 23, 2020
Citizens Bank [Member] \| LIBOR [Member] \| Artesian Resources [Member]
Line of Credit Facility [Abstract]
Variable rate for credit facility	LIBOR
Interest rate	1.00%
CoBank [Member] \| Artesian Resources [Member]
Line of Credit Facility [Abstract]
Line of credit	$ 20,000
Available funds under this line of credit	$ 12,500
CoBank [Member] \| Artesian Water [Member]
Line of Credit Facility [Abstract]
Expiration date of line of credit	Jul. 20, 2020
Patronage refunds	$ 900	$ 1,200
Annual patronage refund rate	0.80%	1.00%
CoBank [Member] \| Artesian Water Maryland [Member]
Line of Credit Facility [Abstract]
Line of credit	$ 10,000
CoBank [Member] \| LIBOR [Member] \| Artesian Water [Member]
Line of Credit Facility [Abstract]
Variable rate for credit facility	LIBOR
Interest rate	1.50%