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

The approximate percentage of irrigation water used by HC and S over the last ten years provided by the West Maui irrigation system.

No definition available.

Name:	alex_ApproximatePercentageOfIrrigationWaterProvidedByWestMauiIrrigationSystem
Namespace Prefix:	alex_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

Guarantee on bonds related to real estate construction projects, which requires the guarantor to make payments to the guaranteed party based on another entity's failure to pay specified obligations, such as debt, to a lender.

No definition available.

Name:	alex_BondsRelatedToRealEstateConstructionProjects
Namespace Prefix:	alex_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

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

No definition available.

Name:	alex_CapacityOfIrrigationWaterSuppliedByAdditionalWatershedLands
Namespace Prefix:	alex_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

Maximum potential amount of future payments (undiscounted) the Company could be required to make to a surety or lender, from whom the company obtained a bond or letter of credit, if the Company fails to perform and the surety or lender has made payment to the obligee or beneficiary.

No definition available.

Name:	alex_ContingentObligationsMaximumExposure
Namespace Prefix:	alex_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Letter of credit amount related to the entity's real estate business.

No definition available.

Name:	alex_LetterOfCreditAmountRelatedToRealEstateBusiness
Namespace Prefix:	alex_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Letter of credit amount that enables the entity to qualify as a self-insurer for state and federal workers' compensation liabilities.

No definition available.

Name:	alex_LetterOfCreditAmountThatEnablesQualificationAsSelfInsurer
Namespace Prefix:	alex_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The number of boilers impacted by the nationwide standards published by the EPA for controlling hazardous air pollutant emissions from industrial, commercial, and institutional boilers and process heaters.

No definition available.

Name:	alex_NumberOfBoilersImpactedByEpaStandards
Namespace Prefix:	alex_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

The number of organizations that filed a petition with the Water Commission to establish IIFS.

No definition available.

Name:	alex_NumberOfOrganizationsThatFiledPetitionToEstablishIifs
Namespace Prefix:	alex_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

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.

Name:	alex_NumberOfPetitionsOnWhichWaterCommissionTookAction
Namespace Prefix:	alex_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

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.

Name:	alex_NumberOfStreamsForWhichIifsWasRequested
Namespace Prefix:	alex_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

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
Namespace Prefix:	alex_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Performance guarantees made on transportation and other matters.

No definition available.

Name:	alex_TransportationAndOtherMattersGuarantees
Namespace Prefix:	alex_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Maximum potential amount of future payments (undiscounted) the Company could be required to make to a surety or lender, from whom the Company obtained a bond letter of credit, if the Company fails to perform and the surety or lender has made payment to the obligee or beneficiary.

No definition available.

Name:	alex_UsCustomsBonds
Namespace Prefix:	alex_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

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

Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

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

-Publisher FASB

-Name FASB Interpretation (FIN)

-Number 45

-Paragraph 13

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 460

-SubTopic 10

-Section 50

-Paragraph 4

-Subparagraph (b)(1)

-URI http://asc.fasb.org/extlink&oid=6851643&loc=d3e12069-110248

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

- Details

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

Amount of a recognized obligation to a multiemployer plan in the event that the employer withdraws from the plan. In some situations, withdrawal from a multiemployer plan may result in an employer having an obligation to the plan for a portion of the unfunded benefit obligation of the pension plans and other postretirement benefit plans.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 13

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.