EQUITY OF AMERICAN ASSETS TRUST, INC. - ATM Equity Program (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2015	Jun. 30, 2014
Equity [Line Items]
Proceeds, net		$ 54,007	$ 69,909
At The Market Equity Program
Equity [Line Items]
Number of shares of common stock issued through ATM programs	1,092,126	1,145,926
Weighted average price per share	$ 40.65	$ 40.74
Proceeds, gross	$ 44,392	$ 46,681
Proceeds, net	43,735	45,899
Commissions | At The Market Equity Program
Equity [Line Items]
Payments of stock issuance costs	(444)	(467)
Other Offering Costs | At The Market Equity Program
Equity [Line Items]
Payments of stock issuance costs	$ (213)	$ (315)