Debt Summary of Total Secured Notes Payable Outstanding (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2014	Dec. 31, 2013	Mar. 29, 2012
Debt Instrument [Line Items]
Notes payable, total		$ 1,069,983
American Assets Trust, L.P.
Debt Instrument [Line Items]
Stated Interest Rate				3.94%
American Assets Trust, L.P. | Waikele Center
Debt Instrument [Line Items]
Stated Interest Rate	[1],[2]	0.00%
Stated Maturity Date	[1],[2]	Nov. 01, 2014
American Assets Trust, L.P. | The Shops at Kalakaua
Debt Instrument [Line Items]
Stated Interest Rate	[1],[3]	5.45%
Stated Maturity Date	[1],[3]	May 01, 2015
American Assets Trust, L.P. | The Land Mark at One Market
Debt Instrument [Line Items]
Stated Interest Rate	[1],[4]	5.61%
Stated Maturity Date	[1],[4]	Jul. 05, 2015
American Assets Trust, L.P. | Del Monte Center
Debt Instrument [Line Items]
Stated Interest Rate	[1],[5]	4.93%
Stated Maturity Date	[1],[5]	Jul. 08, 2015
American Assets Trust, L.P. | First & Main
Debt Instrument [Line Items]
Stated Interest Rate	[1]	3.97%
Stated Maturity Date	[1]	Jul. 01, 2016
American Assets Trust, L.P. | Imperial Beach Gardens
Debt Instrument [Line Items]
Stated Interest Rate	[1]	6.16%
Stated Maturity Date	[1]	Sep. 01, 2016
American Assets Trust, L.P. | Mariner's Point
Debt Instrument [Line Items]
Stated Interest Rate	[1]	6.09%
Stated Maturity Date	[1]	Sep. 01, 2016
American Assets Trust, L.P. | South Bay Marketplace
Debt Instrument [Line Items]
Stated Interest Rate	[1]	5.48%
Stated Maturity Date	[1]	Feb. 10, 2017
American Assets Trust, L.P. | Waikiki Beach Walk - Retail
Debt Instrument [Line Items]
Stated Interest Rate	[1]	5.39%
Stated Maturity Date	[1]	Jul. 01, 2017
American Assets Trust, L.P. | Solana Beach Corporate Centre III-IV
Debt Instrument [Line Items]
Stated Interest Rate	[6]	6.39%
Stated Maturity Date	[6]	Aug. 01, 2017
American Assets Trust, L.P. | Loma Palisades
Debt Instrument [Line Items]
Stated Interest Rate	[1]	6.09%
Stated Maturity Date	[1]	Jul. 01, 2018
American Assets Trust, L.P. | One Beach Street
Debt Instrument [Line Items]
Stated Interest Rate	[1]	3.94%
Stated Maturity Date	[1]	Apr. 01, 2019
American Assets Trust, L.P. | Torrey Reserve - North Court
Debt Instrument [Line Items]
Stated Interest Rate	[6]	7.22%
Stated Maturity Date	[6]	Jun. 01, 2019
American Assets Trust, L.P. | Torrey Reserve-VCI, VCII, VCIII
Debt Instrument [Line Items]
Stated Interest Rate	[6]	6.36%
Stated Maturity Date	[6]	Jun. 01, 2020
American Assets Trust, L.P. | Solana Beach Corporate Centre I-II
Debt Instrument [Line Items]
Stated Interest Rate	[6]	5.91%
Stated Maturity Date	[6]	Jun. 01, 2020
American Assets Trust, L.P. | Solana Beach Towne Centre
Debt Instrument [Line Items]
Stated Interest Rate	[6]	5.91%
Stated Maturity Date	[6]	Jun. 01, 2020
American Assets Trust, L.P. | City Center Bellevue
Debt Instrument [Line Items]
Stated Interest Rate	[1]	3.98%
Stated Maturity Date	[1]	Nov. 01, 2022
Secured Debt | American Assets Trust, L.P.
Debt Instrument [Line Items]
Secured notes payable, Principal Balance		$ 819,983	$ 962,259
Unamortized fair value adjustment		(7,172)	(10,085)
Notes payable, total		$ 812,811	952,174
Number of year amortization schedule		30 years
Secured Debt | American Assets Trust, L.P. | Waikele Center
Debt Instrument [Line Items]
Secured notes payable, Principal Balance	[1],[2]	$ 0	140,700
Secured Debt | American Assets Trust, L.P. | The Shops at Kalakaua
Debt Instrument [Line Items]
Secured notes payable, Principal Balance	[1],[3]	19,000	19,000
Secured Debt | American Assets Trust, L.P. | The Land Mark at One Market
Debt Instrument [Line Items]
Secured notes payable, Principal Balance	[1],[4]	133,000	133,000
Secured Debt | American Assets Trust, L.P. | Del Monte Center
Debt Instrument [Line Items]
Secured notes payable, Principal Balance	[1],[5]	82,300	82,300
Secured Debt | American Assets Trust, L.P. | First & Main
Debt Instrument [Line Items]
Secured notes payable, Principal Balance	[1]	84,500	84,500
Secured Debt | American Assets Trust, L.P. | Imperial Beach Gardens
Debt Instrument [Line Items]
Secured notes payable, Principal Balance	[1]	20,000	20,000
Secured Debt | American Assets Trust, L.P. | Mariner's Point
Debt Instrument [Line Items]
Secured notes payable, Principal Balance	[1]	7,700	7,700
Secured Debt | American Assets Trust, L.P. | South Bay Marketplace
Debt Instrument [Line Items]
Secured notes payable, Principal Balance	[1]	23,000	23,000
Secured Debt | American Assets Trust, L.P. | Waikiki Beach Walk - Retail
Debt Instrument [Line Items]
Secured notes payable, Principal Balance	[1]	130,310	130,310
Secured Debt | American Assets Trust, L.P. | Solana Beach Corporate Centre III-IV
Debt Instrument [Line Items]
Secured notes payable, Principal Balance	[6]	36,376	36,804
Secured Debt | American Assets Trust, L.P. | Loma Palisades
Debt Instrument [Line Items]
Secured notes payable, Principal Balance	[1]	73,744	73,744
Secured Debt | American Assets Trust, L.P. | One Beach Street
Debt Instrument [Line Items]
Secured notes payable, Principal Balance	[1]	21,900	21,900
Secured Debt | American Assets Trust, L.P. | Torrey Reserve - North Court
Debt Instrument [Line Items]
Secured notes payable, Principal Balance	[6]	21,075	21,377
Secured Debt | American Assets Trust, L.P. | Torrey Reserve-VCI, VCII, VCIII
Debt Instrument [Line Items]
Secured notes payable, Principal Balance	[6]	7,101	7,200
Secured Debt | American Assets Trust, L.P. | Solana Beach Corporate Centre I-II
Debt Instrument [Line Items]
Secured notes payable, Principal Balance	[6]	11,302	11,475
Secured Debt | American Assets Trust, L.P. | Solana Beach Towne Centre
Debt Instrument [Line Items]
Secured notes payable, Principal Balance	[6]	37,675	38,249
Secured Debt | American Assets Trust, L.P. | City Center Bellevue
Debt Instrument [Line Items]
Secured notes payable, Principal Balance	[1]	$ 111,000	$ 111,000

[1] Interest only.

[2] Loan repaid in full, without premium or penalty, on October 31, 2014

[3] Loan repaid in full, without premium or penalty, on February 2, 2015.

[4] Maturity Date is the earlier of the loan maturity date under the loan agreement, or the “Anticipated Repayment Date” as specifically defined in the loan agreement, which is the date after which substantial economic penalties apply if the loan has not been paid off.

[5] Loan repaid in full, without premium or penalty, on February 6, 2015.

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