Segment Reporting Reconciliation of Segment Profit to Net Income Attributable to Stockholders (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting [Abstract]
Total segments' profit									$ 246,054	$ 223,454	$ 234,761
General and administrative									(29,879)	(26,581)	(24,871)
Depreciation and amortization									(116,306)	(108,292)	(96,205)
Interest expense									58,587	53,440	54,008
Loss on early extinguishment of debt									(4,271)	0	0
Gain on sale of real estate									0	0	633
Other (expense) income, net									(418)	447	(122)
Net income	$ 10,478	$ 12,895	$ 11,487	$ 1,733	$ 3,788	$ 6,490	$ 9,826	$ 15,484	36,593	35,588	60,188
Net income attributable to restricted shares	(147)	(145)	(135)	(137)	(123)	(87)	(69)	(104)	(564)	(383)	(381)
Net income attributable to unitholders in the Operating Partnership	$ (2,194)	$ (2,709)	$ (2,411)	$ (339)	$ (767)	$ (1,365)	$ (2,101)	$ (3,312)	(7,653)	(7,545)	(14,089)
Income attributable to American Assets Trust, Inc. common stockholders—basic									$ 28,376	$ 27,660	$ 45,718