Equity of American Assets Trust, Inc. Restricted Common Stock Issued (Details) - Restricted Stock - $ / shares	Dec. 01, 2016		Jun. 14, 2016	[1]	Dec. 01, 2015		Jun. 16, 2015	[1]	Dec. 01, 2014		Jun. 17, 2014	[1]	Mar. 25, 2014		Jul. 13, 2013		Jul. 10, 2012		Jan. 19, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights																			2
Award vesting period															3 years		3 years
Award vesting percentage	33.30%				33.30%				33.30%				33.30%		33.30%		33.30%
Granted, Weighted Average Grant Date Fair Value (in USD per share)			$ 40.81				$ 39.64				$ 34.10				$ 31.97	[2]	$ 25.05	[2]
Granted, Shares	143,210	[3]	4,900		93,310	[4]	5,044		98,765	[5]	5,864		112,119	[6]	5,004	[2]	8,015	[2]	2,000	[7]
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, Weighted Average Grant Date Fair Value (in USD per share)	$ 28.24	[3]			$ 13.67	[4]			$ 36.28	[5]			$ 28.89	[6]					$ 11.91	[7]
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, Weighted Average Grant Date Fair Value (in USD per share)	$ 35.71	[3]			$ 26.39	[4]			$ 36.32	[5]			$ 31.25	[6]					$ 12.61	[7]

[1] Restricted common stock issued to members of the company's non-employee directors. These awards of restricted stock will vest subject to the director's continued service on the Board of Directors on the earlier of (i) the one year anniversary of the date of grant or (ii) the date of the next annual meeting of our stockholders, if such non-employee director continues his or her service on the Board of Directors until the next annual meeting of stockholders, but not thereafter, pursuant to our independent director compensation policy.

[2] Restricted common stock issued to members of the company's non-employee directors. These awards of restricted stock vest ratably as to one-third of the shares granted on each of the first three anniversaries of the date of grant, subject to the director's continued service on our Board of Directors.

[3] (7)Restricted common stock issued to certain of the company's senior management and other employees, which are subject to pre-defined market specific performance criteria based vesting. Up to one-third of the shares of restricted stock may vest based on performance calculations determined as of November 30, 2017, 2018 and 2019, subject to the employee's continued employment on those dates.

[4] Restricted common stock issued to certain of the company's senior management and other employees, which are subject to pre-defined market specific performance criteria based vesting. Up to one-third of the shares of restricted stock may vest based on performance calculations determined as of November 30, 2016, 2017 and 2018, subject to the employee's continued employment on those dates.

[5] Restricted common stock issued to certain of the company's senior management and other employees, which are subject to pre-defined market specific performance criteria based vesting. Up to one-third of the shares of restricted stock may vest based on performance calculations determined as of November 30, 2015, 2016 and 2017, subject to the employee's continued employment on those dates.

[6] Restricted common stock issued to certain of the company's senior management and other employees, which are subject to pre-defined market specific performance criteria based vesting. Up to one-third of the shares of restricted stock may vest based on performance calculations determined as of November 30, 2014, 2015 and 2016, subject to the employee's continued employment on those dates.

[7] Restricted common stock issued to certain of the company's senior management and other employees, which are subject to performance-based vesting. These shares vest in two substantially equal installments, with the first installment vested on the third anniversary of the date of grant and the second installment vesting on the fourth anniversary of the date of grant, subject to the employee's continued employment on those dates.