Segment Reporting Reconciliation of Segment Profit to Net Income Attributable to Stockholders (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Segment Reporting [Abstract]
Gross Profit									$ 165,071	$ 149,352	$ 125,906
General and administrative									(17,195)	(15,593)	(13,627)
Depreciation and amortization									(66,775)	(61,853)	(55,936)
Interest expense									(58,020)	(57,328)	(54,580)
Early extinguishment of debt									0	0	(25,867)
Loan transfer and consent fees									0	0	(8,808)
Gain on acquisition									0	0	46,371
Other income (expense), net									(487)	(629)	212
Income from continuing operations					4,822	3,968	2,396	2,763	22,594	13,949	13,671
Discontinued operations
Income from discontinued operations									0	932	1,672
Gain on sale of real estate property									0	36,720	3,981
Results from discontinued operations					36,999	317	228	108	0	37,652	5,653
Net income	6,907	6,258	4,564	4,865	41,821	4,285	2,624	2,871	22,594	51,601	19,324
Net income attributable to restricted shares	(139)	(132)	(133)	(132)	(133)	(133)	(131)	(132)	(536)	(529)	(482)
Net loss attributable to Predecessor's noncontrolling interests in consolidated real estate entities									0	0	2,458
Net income attributable to Predecessor's controlled owners' equity									0	0	(16,995)
Net income attributable to unitholders in the Operating Partnership	(2,086)	(1,903)	(1,354)	(1,495)	(13,111)	(1,335)	(804)	(883)	(6,838)	(16,133)	(1,388)
Net income attributable to American Assets Trust, Inc. stockholders	$ 4,682	$ 4,223	$ 3,077	$ 3,238	$ 28,577	$ 2,817	$ 1,689	$ 1,856	$ 15,220	$ 34,939	$ 2,917