SEGMENT REPORTING - Reconciliation of Segment Profit to Net Income Attributable to Stockholders (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
Segment Reporting [Abstract]
Total segments’ profit	$ 60,993		$ 56,167		$ 115,379	$ 119,297
General and administrative	(6,924)		(6,679)		(13,747)	(13,499)
Depreciation and amortization	(27,646)		(26,493)		(55,147)	(53,955)
Interest expense	(14,862)		(13,331)		(28,867)	(26,803)
Early extinguishment of debt	0		0		(4,271)	0
Other (expense) income, net	(74)		162		(127)	270
NET INCOME	11,487	$ 1,733	9,826	$ 15,484	13,220	25,310
Net income attributable to restricted shares	(135)		(69)		(272)	(173)
Net income attributable to unitholders in the Operating Partnership	2,411		2,101		2,750	5,413
Net income attributable to American Assets Trust, Inc. stockholders	$ 8,941		$ 7,656		$ 10,198	$ 19,724