DEBT - Summary of Total Secured Notes Payable Outstanding (Details) - American Assets Trust, L.P. - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2016		Dec. 31, 2015
First And Main
Debt Instrument [Line Items]
Stated Interest Rate	[1],[2]	3.97%
Stated Maturity Date	[1],[2]	Jul. 01, 2016
Imperial Beach Gardens
Debt Instrument [Line Items]
Stated Interest Rate	[1]	6.16%
Stated Maturity Date	[1]	Sep. 01, 2016
Mariners Point
Debt Instrument [Line Items]
Stated Interest Rate	[1]	6.09%
Stated Maturity Date	[1]	Sep. 01, 2016
South Bay Marketplace
Debt Instrument [Line Items]
Stated Interest Rate	[1]	5.48%
Stated Maturity Date	[1]	Feb. 10, 2017
Waikiki Beach Walk - Retail
Debt Instrument [Line Items]
Stated Interest Rate	[1]	5.39%
Stated Maturity Date	[1]	Jul. 01, 2017
Solana Beach Corporate Centre Three To Four
Debt Instrument [Line Items]
Stated Interest Rate	[3]	6.39%
Stated Maturity Date	[3]	Aug. 01, 2017
Loma Palisades
Debt Instrument [Line Items]
Stated Interest Rate	[1]	6.09%
Stated Maturity Date	[1]	Jul. 01, 2018
One Beach Street
Debt Instrument [Line Items]
Stated Interest Rate	[1]	3.94%
Stated Maturity Date	[1]	Apr. 01, 2019
Torrey Reserve North Court
Debt Instrument [Line Items]
Stated Interest Rate	[3]	7.22%
Stated Maturity Date	[3]	Jun. 01, 2019
Torrey Reserve
Debt Instrument [Line Items]
Stated Interest Rate	[3]	6.36%
Stated Maturity Date	[3]	Jun. 01, 2020
Solana Beach Corporate Centre One To Two
Debt Instrument [Line Items]
Stated Interest Rate	[3]	5.91%
Stated Maturity Date	[3]	Jun. 01, 2020
Solana Beach Towne Centre
Debt Instrument [Line Items]
Stated Interest Rate	[3]	5.91%
Stated Maturity Date	[3]	Jun. 01, 2020
City Center Bellevue
Debt Instrument [Line Items]
Stated Interest Rate	[1]	3.98%
Stated Maturity Date	[1]	Nov. 01, 2022
Secured notes payable, net
Debt Instrument [Line Items]
Long-term Debt, Principal Balance		$ 499,063		$ 584,002
Unamortized fair value adjustment		(3,531)		(4,259)
Debt issuance costs, net		(649)		(743)
Total Debt Outstanding		$ 494,883		579,000
Period of amortization schedule (in years)		30 years
Secured notes payable, net | First And Main
Debt Instrument [Line Items]
Long-term Debt, Principal Balance	[1]	$ 0	[3]	84,500	[2]
Secured notes payable, net | Imperial Beach Gardens
Debt Instrument [Line Items]
Long-term Debt, Principal Balance	[1]	20,000		20,000
Secured notes payable, net | Mariners Point
Debt Instrument [Line Items]
Long-term Debt, Principal Balance	[1]	7,700		7,700
Secured notes payable, net | South Bay Marketplace
Debt Instrument [Line Items]
Long-term Debt, Principal Balance	[1]	23,000		23,000
Secured notes payable, net | Waikiki Beach Walk - Retail
Debt Instrument [Line Items]
Long-term Debt, Principal Balance	[1]	130,310		130,310
Secured notes payable, net | Solana Beach Corporate Centre Three To Four
Debt Instrument [Line Items]
Long-term Debt, Principal Balance	[3]	35,800		35,920
Secured notes payable, net | Loma Palisades
Debt Instrument [Line Items]
Long-term Debt, Principal Balance	[1]	73,744		73,744
Secured notes payable, net | One Beach Street
Debt Instrument [Line Items]
Long-term Debt, Principal Balance	[1]	21,900		21,900
Secured notes payable, net | Torrey Reserve North Court
Debt Instrument [Line Items]
Long-term Debt, Principal Balance	[3]	20,664		20,749
Secured notes payable, net | Torrey Reserve
Debt Instrument [Line Items]
Long-term Debt, Principal Balance	[3]	6,968		6,995
Secured notes payable, net | Solana Beach Corporate Centre One To Two
Debt Instrument [Line Items]
Long-term Debt, Principal Balance	[3]	11,072		11,119
Secured notes payable, net | Solana Beach Towne Centre
Debt Instrument [Line Items]
Long-term Debt, Principal Balance	[3]	36,905		37,065
Secured notes payable, net | City Center Bellevue
Debt Instrument [Line Items]
Long-term Debt, Principal Balance	[1]	$ 111,000		$ 111,000

[1] Interest only.

[2] Loan repaid in full, without premium or penalty, on March 1, 2016.

[3] Principal payments based on a 30-year amortization schedule.