PARTNERS CAPITAL OF AMERICAN ASSETS TRUST, L.P. (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Capital Unit [Line Items]
Antidilutive securities excluded from computation of EPS				419,024,000
Common Shares
Capital Unit [Line Items]
Conversion of operating partnership units (in shares)			5,741
American Assets Trust, L.P.
Capital Unit [Line Items]
Noncontrolling common units	17,899,516		17,899,516
Percentage of ownership interests classified as noncontrolling	28.60%		28.60%
Antidilutive securities excluded from computation of EPS		431,059	211,526	419,024
American Assets Trust, L.P. | Common Shares
Capital Unit [Line Items]
Conversion of operating partnership units (in shares)			5,741
Operating Partnership Units
Capital Unit [Line Items]
Antidilutive securities excluded from computation of EPS	176,767	431,059	211,526,000
Operating Partnership Units | American Assets Trust, L.P.
Capital Unit [Line Items]
Antidilutive securities excluded from computation of EPS	176,767