Consolidated Statement of Equity (Unaudited) - 3 months ended Mar. 31, 2017 - USD ($) $ in Thousands		Total	American Assets Trust, L.P.	American Assets Trust, L.P. Accumulated Other Comprehensive Income (Loss)	American Assets Trust, L.P. Limited Partner	[1]	American Assets Trust, L.P. General Partner		Common Shares	Additional Paid-in Capital	Accumulated Dividends in Excess of Net Income	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interests - Unitholders in the Operating Partnership	Swap	Swap American Assets Trust, L.P.	Swap American Assets Trust, L.P. Accumulated Other Comprehensive Income (Loss)	Swap Accumulated Other Comprehensive Income (Loss)	Swap Noncontrolling Interests - Unitholders in the Operating Partnership	Forward Contracts	Forward Contracts American Assets Trust, L.P.	Forward Contracts American Assets Trust, L.P. Accumulated Other Comprehensive Income (Loss)	Forward Contracts Accumulated Other Comprehensive Income (Loss)	Forward Contracts Noncontrolling Interests - Unitholders in the Operating Partnership
Beginning Balance (in shares) at Dec. 31, 2016									45,732,109
Beginning Balance at Dec. 31, 2016		$ 838,551							$ 457	$ 874,597	$ (77,296)	$ 11,798	$ 28,995
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		10,308	$ 10,308		$ 2,861		$ 7,447	[2]			7,447		2,861
Common shares issued (in shares)									700,000
Common shares issued		30,075							$ 7	30,068
Forfeiture of restricted stock (in shares)									(768)
Forfeiture of restricted stock		0							$ 0	0
Dividends declared and paid		(16,723)									(12,072)		(4,651)
Stock-based compensation		639								639
Other comprehensive loss - change in value of interest rate swaps		(996)	(996)											$ (11,426)	$ (11,426)	$ (11,426)	$ (8,177)	$ (3,249)	$ 10,430	$ 10,430	$ 10,430	$ 7,518	$ 2,912
Reclassification of amortization of forward-starting swap included in interest expense		(145)	(145)	$ (145)								(105)	(40)
Ending Balance (in shares) at Mar. 31, 2017									46,431,341
Ending Balance at Mar. 31, 2017		861,709							$ 464	$ 905,304	(81,921)	11,034	26,828
Beginning partners' capital account (in shares) at Dec. 31, 2016					17,888,822		45,732,109	[2]
Beginning partners' capital account at Dec. 31, 2016			838,551	16,478	$ 24,315		$ 797,758	[2]
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income		10,308	10,308		2,861		$ 7,447	[2]			$ 7,447		2,861
Contributions from American Assets Trust, Inc. (in shares)	[2]						700,000
Contributions from American Assets Trust, Inc.			30,075				$ 30,075	[2]
Forfeiture of restricted units (in shares)	[2]						(768)
Distributions			(16,723)		$ (4,651)		$ (12,072)	[2]
Stock-based compensation			639				$ 639	[2]
Other comprehensive income (loss) - unrealized (loss) on swap derivative during the period		(996)	(996)											$ (11,426)	$ (11,426)	$ (11,426)	$ (8,177)	$ (3,249)	$ 10,430	$ 10,430	$ 10,430	$ 7,518	$ 2,912
Reclassification of amortization of forward-starting swap included in interest expense		$ (145)	(145)	(145)								$ (105)	$ (40)
Ending partners' capital account (in shares) at Mar. 31, 2017					17,888,822		46,431,341	[2]
Ending partners' capital account at Mar. 31, 2017			$ 861,709	$ 15,337	$ 22,525		$ 823,847	[2]

[1] Consists of limited partnership interests held by third parties.

[2] Consists of general partnership interests held by American Assets Trust, Inc.