SEGMENT REPORTING - Reconciliation of Segment Profit to Net Income Attributable to Stockholders (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting [Abstract]
Total segments’ profit	$ 56,167		$ 53,012		$ 119,297	$ 108,489
General and administrative	(6,679)		(5,943)		(13,499)	(12,016)
Depreciation and amortization	(26,493)		(22,582)		(53,955)	(43,165)
Interest expense	(13,331)		(13,129)		(26,803)	(26,478)
Gain on sale of real estate	0		633		0	633
Other income (expense), net	162		(50)		270	(279)
NET INCOME	9,826	$ 15,484	11,941	$ 15,243	25,310	27,184
Net income attributable to restricted shares	(69)		(92)		(173)	(185)
Net income attributable to unitholders in the Operating Partnership	2,101		2,933		5,413	6,988
NET INCOME ATTRIBUTABLE TO AMERICAN ASSETS TRUST, INC. STOCKHOLDERS	$ 7,656		$ 8,916		$ 19,724	$ 20,011