SUBSEQUENT EVENT (Details) (Holding Company Merger [Member])	Feb. 13, 2012
Holding Company Merger [Member]
Subsequent Event [Line Items]
Maximum permitted percentage of common stock of the holding company that may be owned (in hundredths)	22.00%

The maximum permitted percentage of outstanding shares of common stock in the holding company that may be owned (of record or beneficially) or controlled in the aggregate by non-U.S. citizens (as defined by the Jones Act).

No definition available.

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