EQUITY OF AMERICAN ASSETS TRUST, INC. (Details)		3 Months Ended		9 Months Ended
	May 27, 2015 USD ($) Agent	Sep. 30, 2017 USD ($) shares	Sep. 30, 2016 USD ($) shares	Sep. 30, 2017 USD ($) shares	Sep. 30, 2016 USD ($) shares
Equity [Line Items]
Noncash compensation expense		$ 600,000	$ 600,000	$ 1,900,000	$ 1,900,000
Unrecognized compensation expense		$ 2,000,000		$ 2,000,000
Weighted average unvested shares outstanding (in shares) | shares		231,977	169,963	232,041	171,760
At The Market Equity Program
Equity [Line Items]
Number of sales agents | Agent	5
Aggregate offering price of common share	$ 250,000,000.0
Remaining capacity to issue		$ 176,200,000		$ 176,200,000
Operating Partnership Units
Equity [Line Items]
Antidilutive securities excluded from computation of EPS (in shares) | shares		231,977	169,963	232,041	171,760