Reconciliation of Segment Profit to Net Income Attributable to Stockholders (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Segment Reporting Information [Line Items]
Total Segments' profit	$ 41,094	$ 35,390
General and administrative	(4,201)	(3,725)
Depreciation and amortization	(17,013)	(14,854)
Interest expense	(14,736)	(13,901)
Other income (expense), net	(279)	(146)
INCOME FROM CONTINUING OPERATIONS	4,865	2,764
Discontinued operations
Results from discontinued operations		107
Net income	4,865	2,871
Net income attributable to restricted shares	(132)	(132)
Net income attributable to unitholders in the Operating Partnership	(1,495)	(883)
Net income attributable to American Assets Trust, Inc. stockholders	$ 3,238	$ 1,856