XML 37 R26.htm IDEA: XBRL DOCUMENT v3.8.0.1

REGULATORY PROCEEDINGS (Details) - USD ($)				3 Months Ended		9 Months Ended
	Nov. 29, 2016	May 31, 2016	Nov. 24, 2015	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Other Proceedings [Abstract]
Percentage of Distribution System Improvement Charges annual rate increase application filed by company to regulatory	4.71%	2.30%	1.57%
Increase Amount Based On Eligible Plant Improvements Since Last Rate Increase	$ 16,600,000	$ 10,300,000	$ 7,000,000
Delaware [Member]
Rate Proceedings [Abstract]
Percentage of gross water sales						15.00%
Period to complete rate case by law						7 months
Delaware [Member] | Maximum [Member]
Rate Proceedings [Abstract]
Temporary annual rate increase subject to 15% gross water sales limitation						$ 2,500,000
Percentage of rate relief allowed should a rate case not complete						15.00%
Other Proceedings [Abstract]
Distribution System Improvement Charge rate increase applied between base rate filings						7.50%
Distribution System Improvement Charge rate increase within a 12-month period						5.00%
Artesian Water [Member]
Other Proceedings [Abstract]
Revenue earned in DSIC rate increases				$ 858,000	$ 432,000	$ 2,400,000	$ 938,000

X

- Definition

For a first temporary increase in revenue basis, maximum temporary annual rate charge increase subject to specific gross water sales limitation.

+ References

No definition available.

+ Details

Name:	artna_AmountOfTemporaryRateIncreasePerRateSettingProcess
Namespace Prefix:	artna_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

Ceiling percentage of Distribution System Improvement Charge rate subject to amount billed to customers.

+ References

No definition available.

+ Details

Name:	artna_DistributionSystemImprovementChargeRateCeilingPercentage
Namespace Prefix:	artna_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Conditional percentage maximum for increasing Distribution System Improvement Charge rate within a 12-month period.

+ References

No definition available.

+ Details

Name:	artna_DistributionSystemImprovementChargeRateConditionalIncrease
Namespace Prefix:	artna_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Increase amount based on eligible plant improvements since the last rate increase.

+ References

No definition available.

+ Details

Name:	artna_IncreaseAmountBasedOnEligiblePlantImprovementsSinceLastRateIncrease
Namespace Prefix:	artna_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- References

No definition available.

+ Details

Name:	artna_OtherProceedingsAbstract
Namespace Prefix:	artna_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Percentage of Distribution System Improvement Charge rate increase application filed by company to regulatory.

+ References

No definition available.

+ Details

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

X

- Definition

For a first temporary annual rate increase in revenue basis, maximum percentage of gross water sales increase allowed subject to specific dollar amount limitation.

+ References

No definition available.

+ Details

Name:	artna_PercentageOfGrossWaterSalesMaximumTemporaryAnnualRateIncreaseSubjectToCeilingLimitation
Namespace Prefix:	artna_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Percentage of relief that utility may put into effect if condition for rate case period completion not fulfilled by law.

+ References

No definition available.

+ Details

Name:	artna_PercentageOfReliefIfRateCasePeriodConditionNotFulfill
Namespace Prefix:	artna_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Period within which rate change case is to complete, by law, after which, entire requested rate relief may go into effect.

+ References

No definition available.

+ Details

Name:	artna_PeriodToCompleteRateChangeApplicationCaseByLaw
Namespace Prefix:	artna_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

X

- References

No definition available.

+ Details

Name:	artna_RateProceedingsAbstract
Namespace Prefix:	artna_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Revenue earned due to Distribution System Improvement Charge rate increase.

+ References

No definition available.

+ Details

Name:	artna_RevenueEarnedInDistributionSystemImprovementCharge
Namespace Prefix:	artna_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Details

Name:	us-gaap_StatementGeographicalAxis=stpr_DE
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

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