SEGMENT REPORTING - Reconciliation of Segment Profit to Net Income Attributable to Stockholders (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Segment Reporting [Abstract]
Total Segments' profit	$ 55,477	$ 51,766
General and administrative	(6,073)	(5,567)
Depreciation and amortization	(20,583)	(33,279)
Interest expense	13,349	13,820
Other (expense) income, net	(229)	209
NET INCOME (LOSS)	15,243	(691)
Net (income) loss attributable to restricted shares	(93)	72
Net (income) loss attributable to unitholders in the Operating Partnership	4,055	(166)
NET INCOME (LOSS) ATTRIBUTABLE TO AMERICAN ASSETS TRUST, INC. STOCKHOLDERS	$ 11,095	$ (453)