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The capacity of irrigation water used by HC and S supplied by the additional watershed lands over the last ten years.

No definition available.

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Loss Contingency, Noncompliant Boilers, Number

No definition available.

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Loss Contingency, Non-compliant Period

No definition available.

Name:	alex_LossContingencyNoncompliantPeriod
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The number of petitions on which the Water Commission to action, which resulted in some quantity of water being returned to the streams rather than being utilized for irrigation purposes, as per the IIFS request.

No definition available.

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Namespace Prefix:	alex_
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The number of streams for which interim instream flow standards (IIFS) was requested via petitions filed by a third party to the Commission on Water Resource Management of the state of Hawaii.

No definition available.

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The number of water licenses held by the entity, which provides access to another 30,000 acres owned by the State of Hawaii in East Maui. All of these licenses were extended as revocable permits that are renewed annually.

No definition available.

Name:	alex_NumberOfWaterLicensesHeldAndExtendedAsRevocablePermits
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Data Type:	xbrli:integerItemType
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Period provided by the irrigation system for water use.

No definition available.

Name:	alex_PeriodProvidedByIrrigationSystem
Namespace Prefix:	alex_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

The number of acres of watershed lands in East Maui owned by the entity.

No definition available.

Name:	alex_WatershedLandsInEastMauiOwned
Namespace Prefix:	alex_
Data Type:	num:areaItemType
Balance Type:	na
Period Type:	instant

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.

No definition available.

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Reflects the estimated amount of loss from the specified contingency as of the balance sheet date.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section 50

-Paragraph 4

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14435-108349

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section 50

-Paragraph 9

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14557-108349

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The estimated maximum amount of possible loss from the contingency.

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Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=alex_LongTermWaterLeaseRequestMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=alex_PetitionsFiledRequestingIifsInEastMauiStreamsMember
Namespace Prefix:
Data Type:	na
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