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The minimum percentage of contributions to the plan, based on pre-defined criteria (e.g. eligible employee compensation or Company performance above minimum threshold).

No definition available.

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Namespace Prefix:	alex_
Data Type:	num:percentItemType
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The number of multiemployer plans.

No definition available.

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Namespace Prefix:	alex_
Data Type:	xbrli:integerItemType
Balance Type:	na
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The number of multiemployer plans with estimated withdrawal obligation. The remaining plans do not have a withdrawal liability.

No definition available.

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Namespace Prefix:	alex_
Data Type:	xbrli:integerItemType
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- Details

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Data Type:	xbrli:stringItemType
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The amount of the cost recognized during the period for defined contribution plans.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 11

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 715

-SubTopic 70

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6414718&loc=d3e28014-114942

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Data Type:	xbrli:monetaryItemType
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General descriptive information regarding an employer's multiemployer plans. A multiemployer plan is a plan to which two or more unrelated employers contribute, usually pursuant to one or more collective-bargaining agreements. A characteristic of multiemployer plans is that assets contributed by one participating employer may be used to provide benefits to employees of other participating employers since assets contributed by one employer are not segregated in a separate account or restricted to provide benefits only to employees of that employer. A multiemployer plan is usually administered by a board of trustees composed of management and labor representatives and may also be referred to as a "joint trust" or "union" plan. Generally, many employers participate in a multiemployer plan, and an employer may participate in more than one plan. The employers participating in multiemployer plans usually have a common industry bond, but for some plans the employers are in different industries and the labor union may be their only common bond.

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

-Publisher FASB

-Name Accounting Standards Codification

-Section 50

-Paragraph 1

-SubTopic 80

-Topic 715

-URI http://asc.fasb.org/extlink&oid=6958064&loc=d3e29142-114947

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 12

-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 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 87

-Paragraph 67

-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 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Multiemployer Plan

-URI http://asc.fasb.org/extlink&oid=6517991

Name:	us-gaap_DescriptionOfMultiemployerPlan
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
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Amount of contributions made to multiemployer plans for each period for which a statement of income is presented. An employer may disclose total contributions to multiemployer plans without disaggregating the amounts attributable to 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 12

-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

-Section 50

-Paragraph 1

-SubTopic 80

-Topic 715

-URI http://asc.fasb.org/extlink&oid=6958064&loc=d3e29142-114947

Name:	us-gaap_MultiemployerPlanPeriodContributions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_MultiemployerPlansAbstract
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.