SEGMENT REPORTING - Reconciliation of Segment Profit to Net Income Attributable to Stockholders (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment Reporting [Abstract]
Total Segments' profit	$ 49,361	$ 45,812	$ 95,758	$ 91,457
General and administrative	(5,131)	(4,394)	(10,213)	(8,943)
Depreciation and amortization	(24,182)	(17,714)	(42,168)	(35,167)
Interest expense	12,652	13,153	25,983	26,099
Other income, net	192	99	502	123
NET INCOME	7,588	10,650	17,896	21,371
Net income attributable to restricted shares	(61)	(43)	(121)	(86)
Net income attributable to unitholders in the Operating Partnership	2,008	3,008	4,869	6,035
NET INCOME ATTRIBUTABLE TO AMERICAN ASSETS TRUST, INC. STOCKHOLDERS	$ 5,519	$ 7,599	$ 12,906	$ 15,250