Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2017	Dec. 31, 2016
Common Shares
Common stock, par value (in USD per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	490,000,000	490,000,000
Common stock, shares outstanding (in shares)	47,130,063	45,732,109
Common stock, shares issued (in shares)	47,130,063	45,732,109
American Assets Trust, L.P.
Limited partners' capital, units issued (in shares)	17,194,980	17,888,822
Limited partners' capital, units outstanding (in shares)	17,194,980	17,888,822
General partners' capital, units issued (in shares)	47,130,063	45,732,109
General partners' capital, units outstanding (in shares)	47,130,063	45,732,109