EQUITY OF AMERICAN ASSETS TRUST, INC. - ATM Equity Program (Details) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($) $ / shares shares
Equity [Line Items]
Proceeds from issuance of common stock	$ 7,034
At The Market Equity Program
Equity [Line Items]
Common shares issued (in shares) | shares	162,531
Weighted average price per share | $ / shares	$ 45.53
Proceeds, gross	$ 7,401
At The Market Equity Program | Sales agent compensation
Equity [Line Items]
Sales agent compensation and offering costs	(74)
At The Market Equity Program | Other offering costs
Equity [Line Items]
Sales agent compensation and offering costs	$ (293)