SUBSEQUENT EVENT (Details) - Subsequent Event - American Assets Trust, L.P. - Eastgate Office Park [Member] $ in Millions	Jul. 07, 2021 USD ($) ft²
Subsequent Event [Line Items]
Area of Real Estate Property \| ft²	280,000
Payments to Acquire Productive Assets \| $	$ 125

The cash outflow for purchases of and capital improvements on property, plant and equipment (capital expenditures), software, and other intangible assets.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3213-108585

Name:	us-gaap_PaymentsToAcquireProductiveAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration