EQUITY OF AMERICAN ASSETS TRUST, INC. (Details)			3 Months Ended
	Mar. 02, 2018 Agent	May 27, 2015 USD ($) Agent	Mar. 31, 2018 USD ($) shares	Mar. 31, 2017 USD ($) shares
Equity [Line Items]
Noncash compensation expense			$ 700,000	$ 600,000
Unrecognized compensation expense			$ 3,300,000
Weighted average unvested shares outstanding (in shares) | shares			263,606	232,099
At The Market Equity Program
Equity [Line Items]
Number of sales agents | Agent	1	5
Aggregate offering price of common share		$ 250,000,000.0
Remaining capacity to issue			$ 176,200,000
Operating Partnership Units
Equity [Line Items]
Antidilutive securities excluded from computation of EPS (in shares) | shares			17,458,586	232,099