EQUITY OF AMERICAN ASSETS TRUST, INC. (Details)			3 Months Ended		6 Months Ended
	Mar. 09, 2015 USD ($) $ / shares shares	May. 06, 2013 USD ($) Agent	Jun. 30, 2015 USD ($) shares	Jun. 30, 2014 USD ($) shares	Jun. 30, 2015 USD ($) shares	Jun. 30, 2014 USD ($) shares	May. 27, 2015 USD ($)
Equity [Line Items]
Noncash compensation expense | $			$ 800,000	$ 1,000,000	$ 1,700,000	$ 1,500,000
Unrecognized compensation expense | $			$ 3,200,000		$ 3,200,000
Weighted average unvested shares outstanding			176,767	431,059	211,526	419,024
Antidilutive securities excluded from computation of EPS						419,024,000
At The Market Equity Program
Equity [Line Items]
Number of sales agents | Agent		4
Aggregate offering price of common share | $		$ 150,000,000.0					$ 250,000,000
Remaining capacity to issue | $			$ 235,700,000		$ 235,700,000
Common shares issued (in shares)			1,092,126		1,145,926
Gross proceeds from issuance of common stock | $			$ 44,392,000		$ 46,681,000
Explorer Insurance Company | Board of Directors Chairman | Private Placement
Equity [Line Items]
Common shares issued (in shares)	200,000
Share price (in dollars per share) | $ / shares	$ 40.54
Gross proceeds from issuance of common stock | $	$ 8,100,000
Operating Partnership Units
Equity [Line Items]
Antidilutive securities excluded from computation of EPS			176,767	431,059	211,526,000
Restricted Stock Units (RSUs)
Equity [Line Items]
Granted, Shares					5,044