SEGMENT REPORTING - Reconciliation of Segment Profit to Net Income Attributable to Stockholders (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Segment Reporting [Abstract]
Total Segments' profit	$ 47,989	$ 45,628	$ 139,446	$ 132,573
General and administrative	(4,513)	(6,357)	(13,456)	(16,161)
Depreciation and amortization	(17,992)	(15,761)	(53,159)	(46,154)
Interest expense	13,049	11,258	39,148	34,250
Gain on sale of real estate	0	7,121	0	7,121
Other expense, net	(577)	(347)	(454)	(440)
NET INCOME	11,858	19,026	33,229	42,689
Net income attributable to restricted shares	(42)	(32)	(128)	(115)
Net income attributable to unitholders in the Operating Partnership	3,342	5,432	9,377	12,277
NET INCOME ATTRIBUTABLE TO AMERICAN ASSETS TRUST, INC. STOCKHOLDERS	$ 8,474	$ 13,562	$ 23,724	$ 30,297