SEGMENT REPORTING - Reconciliation of Segment Profit to Net Income Attributable to Stockholders (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Segment Reporting [Abstract]
Total Segments' profit	$ 45,812	$ 43,578	$ 91,457	$ 86,945
General and administrative	(4,394)	(4,788)	(8,943)	(9,804)
Depreciation and amortization	(17,714)	(15,286)	(35,167)	(30,393)
Interest expense	13,153	11,197	26,099	22,992
Other income (expense), net	99	(23)	123	(93)
NET INCOME	10,650	12,284	21,371	23,663
Net income attributable to restricted shares	(43)	(40)	(86)	(83)
Net income attributable to unitholders in the Operating Partnership	3,008	3,536	6,035	6,845
NET INCOME ATTRIBUTABLE TO AMERICAN ASSETS TRUST, INC. STOCKHOLDERS	$ 7,599	$ 8,708	$ 15,250	$ 16,735