The maximum contractual term (in years) of awards granted.

No definition available.

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- Definition

The minimum percentage of fair market value (defined as the closing market price) that is allowed for the exercise price of stock options granted under the Plan.

+ References

No definition available.

+ Details

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- Definition

The number of programs that generally awarded share-based compensation, under the Plan.

+ References

No definition available.

+ Details

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

- Definition

The number of separate incentive compensation programs of which the Plan consists.

+ References

No definition available.

+ Details

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- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Performance Measurement Period

+ References

No definition available.

+ Details

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- Definition

Number of common shares reserved for future issuance related to deferred compensation arrangements with individuals.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

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- Definition

The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(2)(iii)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

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Data Type:	num:perShareItemType
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- Details

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- Definition

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Gross number of share options (or share units) granted during the period.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Details

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- Details

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- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_RestrictedStockUnitsRSUMember
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- Details

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- Details

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- Details

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Data Type:	na
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- Details

Name:	us-gaap_VestingAxis=alex_TimeBasedVestingMember
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Share-Based Awards (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014 Program	Dec. 31, 2012	Dec. 31, 2013	Jun. 30, 2012
2012 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for issuance (in shares)				4.3
Stock available for future issuance (in shares)	1.4
Number of shares granted during period		2.7
Number of separate incentive compensation programs	4
Number of programs that generally award share based compensation	3
2012 Plan, Discretionary Grant Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Minimum percentage of fair market value allowed for exercise price of stock options granted	100.00%
Vesting period	3 years
Maximum contractual term of awards granted	10 years
2012 Plan, Automatic Grant Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Performance Shares \| 2012 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	2 years
Number of measurement periods of total shareholder return	2 years
Restricted Stock Units (RSUs) \| 2012 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average fair value (in dollars per share)	39.38
Restricted Stock Units and Performance Shares Units \| 2012 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average fair value (in dollars per share)	39.38		$ 34.12
Time-Based Vesting \| Restricted Stock Units (RSUs) \| 2012 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years