Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016		Dec. 31, 2015
REVENUE:
Rental income	$ 298,803	$ 279,498		$ 261,887
Other property income	16,180	15,590		13,736
Total revenue	314,983	295,088		275,623
EXPENSES:
Rental expenses	84,006	79,553		73,187
Real estate taxes	32,671	28,378		24,819
General and administrative	21,382	17,897		20,074
Depreciation and amortization	83,278	71,319		63,392
Total operating expenses	221,337	197,147		181,472
Operating income (loss)	93,646	97,941		94,151
Interest expense	(53,848)	(51,936)		(47,260)
Gain on sale of real estate	0	0		7,121
Other income (expense), net	334	(368)		(97)
Net income	40,132	45,637		53,915
Net income attributable to restricted shares	(241)	(189)		(168)
Net income attributable to unitholders in the Operating Partnership	(10,814)	(12,863)		(15,238)
NET INCOME ATTRIBUTABLE TO AMERICAN ASSETS TRUST, INC. STOCKHOLDERS	$ 29,077	$ 32,585		$ 38,509
EARNINGS PER COMMON SHARE, BASIC
Basic net income attributable to common stockholders per share (in dollars per share)	$ 0.62	$ 0.72		$ 0.87
Weighted average shares of common stock outstanding-basic (in shares)	46,715,520	45,332,471		44,439,112
EARNINGS PER COMMON SHARE, DILUTED
Diluted net income attributable to common stockholders per share (in dollars per share)	$ 0.62	$ 0.72		$ 0.86
Weighted average shares of common stock outstanding-diluted (in shares)	64,087,250	63,228,159		62,339,163
COMPREHENSIVE INCOME
Net income	$ 40,132	$ 45,637		$ 53,915
Other comprehensive gain (loss) - unrealized gain (loss) on swap derivative during the period	386	17,048
Reclassification of amortization of forward starting swap included in interest expense	(1,114)	(231)		(231)
Comprehensive income	39,404	62,454		53,446
Comprehensive income attributable to non-controlling interest	(10,433)	(17,624)		(15,119)
Comprehensive income attributable to American Assets Trust, Inc.	28,971	44,830		38,327
American Assets Trust, L.P.
REVENUE:
Rental income	298,803	279,498		261,887
Other property income	16,180	15,590		13,736
Total revenue	314,983	295,088		275,623
EXPENSES:
Rental expenses	84,006	79,553		73,187
Real estate taxes	32,671	28,378		24,819
General and administrative	21,382	17,897		20,074
Depreciation and amortization	83,278	71,319		63,392
Total operating expenses	221,337	197,147		181,472
Operating income (loss)	93,646	97,941		94,151
Interest expense	(53,848)	(51,936)		(47,260)
Gain on sale of real estate	0	0		7,121
Other income (expense), net	334	(368)		(97)
Net income	40,132	45,637		53,915
Net income attributable to restricted shares	(241)	(189)		(168)
NET INCOME ATTRIBUTABLE TO AMERICAN ASSETS TRUST, INC. STOCKHOLDERS	$ 39,891	$ 45,448		$ 53,747
EARNINGS PER COMMON SHARE, BASIC
Basic net income attributable to common stockholders per share (in dollars per share)	$ 0.62	$ 0.72		$ 0.86
Weighted average shares of common stock outstanding-basic (in shares)	64,087,250	63,228,159		62,339,163
EARNINGS PER COMMON SHARE, DILUTED
Diluted net income attributable to common stockholders per share (in dollars per share)	$ 0.62	$ 0.72		$ 0.86
Weighted average shares of common stock outstanding-diluted (in shares)	64,087,250	63,228,159		62,339,163
DISTRIBUTIONS PER UNIT (in dollars per share)	$ 1.05	$ 1.01		$ 0.9475
COMPREHENSIVE INCOME
Net income	$ 40,132	$ 45,637		$ 53,915
Other comprehensive gain (loss) - unrealized gain (loss) on swap derivative during the period	386	17,048
Reclassification of amortization of forward starting swap included in interest expense	(1,114)	(231)		(231)
Comprehensive income	39,404	62,454		53,446
American Assets Trust, L.P. | Limited Partner
EXPENSES:
Net income	10,814	12,863	[1]	15,238	[1]
COMPREHENSIVE INCOME
Net income	10,814	12,863	[1]	15,238	[1]
Comprehensive income attributable to American Assets Trust, Inc.	(10,433)	(17,624)		(15,119)
American Assets Trust, L.P. | General Partner
EXPENSES:
Net income	29,318	32,774	[2]	38,677	[2]
COMPREHENSIVE INCOME
Net income	29,318	32,774	[2]	38,677	[2]
Comprehensive income attributable to American Assets Trust, Inc.	28,971	44,830		38,327
Swap
COMPREHENSIVE INCOME
Other comprehensive gain (loss) - unrealized gain (loss) on swap derivative during the period	(10,281)	17,048		(238)
Swap | American Assets Trust, L.P.
COMPREHENSIVE INCOME
Other comprehensive gain (loss) - unrealized gain (loss) on swap derivative during the period	(10,281)	$ 17,048		$ (238)
Forward Contracts
COMPREHENSIVE INCOME
Other comprehensive gain (loss) - unrealized gain (loss) on swap derivative during the period	10,667
Forward Contracts | American Assets Trust, L.P.
COMPREHENSIVE INCOME
Other comprehensive gain (loss) - unrealized gain (loss) on swap derivative during the period	$ 10,667

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

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