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

[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.