American Assets Trust (AAT) 10-K 20 Feb 15 2014 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
	Dec. 31, 2014	Feb. 20, 2015	Jun. 30, 2014
Document Information [Line Items]
Document Type	10-K
Amendment Flag	FALSE
Document Period End Date	31-Dec-14
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Trading Symbol	AAT
Entity Registrant Name	AMERICAN ASSETS TRUST, INC.
Entity Central Index Key	1500217
Current Fiscal Year End Date	-19
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		43,567,365
Entity Public Float			$1,256,800,000
American Assets Trust, L.P.
Document Information [Line Items]
Document Type	10-K
Amendment Flag	FALSE
Document Period End Date	31-Dec-14
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Entity Registrant Name	AMERICAN ASSETS TRUST, L.P.
Entity Central Index Key	1509570
Current Fiscal Year End Date	-19
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	No
Entity Voluntary Filers	Yes
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		0
Entity Public Float			$0

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
ASSETS
Operating real estate	$1,931,698	$1,919,015
Construction in progress	195,736	67,389
Held for development	9,390	9,013
Total Real estate, at cost	2,136,824	1,995,417
Accumulated depreciation	-361,424	-318,581
Net real estate	1,775,400	1,676,836
Cash and cash equivalents	59,357	48,987	42,479
Restricted cash	10,994	9,124
Accounts receivable, net	6,727	7,295
Deferred rent receivables, net	35,883	32,531
Other assets, net	53,401	57,670
TOTAL ASSETS	1,941,762	1,832,443
LIABILITIES AND EQUITY
Secured notes payable	812,811	952,174
Unsecured notes payable	250,000	0
Unsecured line of credit	0	93,000
Accounts payable and accrued expenses	50,861	37,063
Security deposits payable	5,521	5,163
Other liabilities and deferred credits	55,993	58,465
Total liabilities	1,175,186	1,145,865
Commitments and contingencies (Note 13)
American Assets Trust, Inc. stockholders' equity
Common stock, $0.01 par value, 490,000,000 shares authorized, 43,701,669 and 40,512,563 shares issued and outstanding at December 31, 2014 and 2013, respectively	437	405
Additional paid-in capital	795,065	692,196
Accumulated dividends in excess of net income	-60,291	-44,090
Accumulated other comprehensive income	92	0
Total American Assets Trust, Inc. stockholders' equity	735,303	648,511
Noncontrolling interests	31,273	38,067
Total equity	766,576	686,578	685,729
TOTAL LIABILITIES AND EQUITY	1,941,762	1,832,443
American Assets Trust, L.P.
ASSETS
Operating real estate	1,931,698	1,919,015
Construction in progress	195,736	67,389
Held for development	9,390	9,013
Total Real estate, at cost	2,136,824	1,995,417
Accumulated depreciation	-361,424	-318,581
Net real estate	1,775,400	1,676,836
Cash and cash equivalents	59,357	48,987	42,479
Restricted cash	10,994	9,124
Accounts receivable, net	6,727	7,295
Deferred rent receivables, net	35,883	32,531
Other assets, net	53,401	57,670
TOTAL ASSETS	1,941,762	1,832,443
LIABILITIES AND EQUITY
Secured notes payable	812,811	952,174
Unsecured notes payable	250,000	0
Unsecured line of credit	0	93,000
Accounts payable and accrued expenses	50,861	37,063
Security deposits payable	5,521	5,163
Other liabilities and deferred credits	55,993	58,465
Total liabilities	1,175,186	1,145,865
American Assets Trust, Inc. stockholders' equity
Accumulated other comprehensive income	130	0
TOTAL LIABILITIES AND EQUITY	1,941,762	1,832,443
Partners' Capital [Abstract]
Limited partners' capital, 17,905,257 and 17,917,109 units issued and outstanding as of December 31, 2014 and December 31, 2013, respectively	31,235	38,067
General partners' capital, 43,701,669 and 40,512,563 units issued and outstanding as of December 31, 2014 and December 31, 2013, respectively	735,211	648,511
Total capital	$766,576	$686,578	$685,729

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Common stock, par value	$0.01	$0.01
Common stock, shares authorized	490,000,000	490,000,000
Common stock, shares outstanding	43,701,669	40,512,563
American Assets Trust, L.P.
Limited Partners' Capital Account, Units Issued	17,905,257	17,917,109
Limited Partners' Capital Account, Units Outstanding	17,905,257	17,917,109
General Partners' Capital Account, Units Issued	43,701,669	40,512,563
General Partners' Capital Account, Units Outstanding	43,701,669	40,512,563

Consolidated_Statements_of_Inc

Consolidated Statements of Income (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
REVENUE:
Rental income	$246,078	$242,757	$225,249
Other property income	13,922	12,300	10,217
Total revenue	260,000	255,057	235,466
EXPENSES:
Rental expenses	68,267	68,608	64,089
Real estate taxes	22,964	21,378	22,025
General and administrative	18,532	17,195	15,593
Depreciation and amortization	66,568	66,775	61,853
Total operating expenses	176,331	173,956	163,560
Operating income (loss)	83,669	81,101	71,906
Interest expense	-52,965	-58,020	-57,328
Other income (expense), net	441	-487	-629
INCOME FROM CONTINUING OPERATIONS	31,145	22,594	13,949
Discontinued operations
Income from discontinued operations	0	0	932
Gain on sale of real estate property	0	0	36,720
Results from discontinued operations	0	0	37,652
NET INCOME	31,145	22,594	51,601
Net income attributable to restricted shares	-374	-536	-529
Net income attributable to unitholders in the Operating Partnership	-9,015	-6,838	-16,134
NET INCOME ATTRIBUTABLE TO AMERICAN ASSETS TRUST, INC. STOCKHOLDERS	21,756	15,220	34,938
EARNINGS PER COMMON SHARE, BASIC
Continuing operations (in dollars per share)	$0.52	$0.38	$0.24
Discontinued operations (in dollars per share)	$0	$0	$0.66
Basic net income attributable to common stockholders per share (in dollars per share)	$0.52	$0.38	$0.90
Weighted average shares of common stock outstanding-basic (in shares)	42,041,126	39,539,457	38,736,113
EARNINGS PER COMMON SHARE, DILUTED
Continuing operations (in dollars per share)	$0.51	$0.38	$0.24
Discontinued operations (in dollars per share)	$0	$0	$0.66
Diluted net income attributable to common stockholders per share (in dollars per share)	$0.51	$0.38	$0.90
Weighted average shares of common stock outstanding-diluted (in shares)	59,947,474	57,515,810	57,053,909
COMPREHENSIVE INCOME
Net income	31,145	22,594	51,601
Reclassification of amortization of forward starting swap included in interest expense	-39	0	0
Comprehensive income	31,275	22,594	51,601
Comprehensive income attributable to non-controlling interest	-9,053	-6,838	-16,134
Comprehensive income attributable to American Assets Trust, Inc.	22,222	15,756	35,467
American Assets Trust, L.P.
REVENUE:
Rental income	246,078	242,757	225,249
Other property income	13,922	12,300	10,217
Total revenue	260,000	255,057	235,466
EXPENSES:
Rental expenses	68,267	68,608	64,089
Real estate taxes	22,964	21,378	22,025
General and administrative	18,532	17,195	15,593
Depreciation and amortization	66,568	66,775	61,853
Total operating expenses	176,331	173,956	163,560
Operating income (loss)	83,669	81,101	71,906
Interest expense	-52,965	-58,020	-57,328
Other income (expense), net	441	-487	-629
INCOME FROM CONTINUING OPERATIONS	31,145	22,594	13,949
Discontinued operations
Income from discontinued operations	0	0	932
Gain on sale of real estate property	0	0	36,720
Results from discontinued operations	0	0	37,652
NET INCOME	31,145	22,594	51,601
Net income attributable to restricted shares	-374	-536	-529
Net income attributable to unitholders in the Operating Partnership	-9,015	-6,838	-16,134
NET INCOME ATTRIBUTABLE TO AMERICAN ASSETS TRUST, INC. STOCKHOLDERS	21,756	15,220	34,938
EARNINGS PER COMMON SHARE, BASIC
Continuing operations (in dollars per share)	$0.52	$0.38	$0.24
Discontinued operations (in dollars per share)	$0	$0	$0.66
Basic net income attributable to common stockholders per share (in dollars per share)	$0.52	$0.38	$0.90
Weighted average shares of common stock outstanding-basic (in shares)	42,041,126	39,539,457	38,736,113
EARNINGS PER COMMON SHARE, DILUTED
Continuing operations (in dollars per share)	$0.51	$0.38	$0.24
Discontinued operations (in dollars per share)	$0	$0	$0.66
Diluted net income attributable to common stockholders per share (in dollars per share)	$0.51	$0.38	$0.90
Weighted average shares of common stock outstanding-diluted (in shares)	59,947,474	57,515,810	57,053,909
DISTRIBUTIONS PER UNIT	$0.89	$0.85	$0.84
COMPREHENSIVE INCOME
Net income	31,145	22,594	51,601
Reclassification of amortization of forward starting swap included in interest expense	-39	0	0
Comprehensive income	31,275	22,594	51,601
Limited Partner | American Assets Trust, L.P.
Discontinued operations
NET INCOME	9,015	6,838	16,134
COMPREHENSIVE INCOME
Net income	9,015	6,838	16,134
Comprehensive income attributable to American Assets Trust, Inc.	-9,053	-6,838	-16,134
General Partner | American Assets Trust, L.P.
Discontinued operations
NET INCOME	22,130	15,756	35,467
COMPREHENSIVE INCOME
Net income	22,130	15,756	35,467
Comprehensive income attributable to American Assets Trust, Inc.	22,222	15,756	35,467
Swap
COMPREHENSIVE INCOME
Other comprehensive loss - unrealized loss on swap derivative during the period	-1,448	0	0
Swap | American Assets Trust, L.P.
COMPREHENSIVE INCOME
Other comprehensive loss - unrealized loss on swap derivative during the period	-1,448
Forward Contracts
COMPREHENSIVE INCOME
Other comprehensive loss - unrealized loss on swap derivative during the period	1,617	0	0
Forward Contracts | American Assets Trust, L.P.
COMPREHENSIVE INCOME
Other comprehensive loss - unrealized loss on swap derivative during the period	$1,617

Consolidated_Statements_of_Equ

Consolidated Statements of Equity (USD $)	Total	Common Stock	Additional Paid-in Capital	Accumulated dividends in excess of net income	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interests - Unitholders in the Operating Partnership	American Assets Trust, L.P.	Swap	Swap	Swap	Swap	Forward Contracts	Forward Contracts	Forward Contracts	Forward Contracts	Limited Partner	General Partner	Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss)
In Thousands, except Share data, unless otherwise specified									Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interests - Unitholders in the Operating Partnership	American Assets Trust, L.P.		Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interests - Unitholders in the Operating Partnership	American Assets Trust, L.P.	American Assets Trust, L.P.	American Assets Trust, L.P.	American Assets Trust, L.P.	Swap	Forward Contracts
																			American Assets Trust, L.P.	American Assets Trust, L.P.
Partners' Capital at Dec. 31, 2011							$679,728									$53,697	$626,031	$0
Beginning Balance at Dec. 31, 2011	679,728	393	653,645	-28,007	0	53,697
Partners' Capital Account, Units at Dec. 31, 2011																18,396,089	39,283,796
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	51,601			35,467		16,134	51,601									16,134	35,467
Conversion of operating partnership units (in shares)		372,654
Conversion of operating partnership units		4	7,092			-7,096
Issuance of restricted stock (in shares)		10,015
Forfeiture of restricted stock (in shares)		-2,253
Dividends declared and paid	-48,452			-33,085		-15,367
Stock-based compensation	2,852		2,852
Other comprehensive income (loss) unrealized gain (loss) on derivatives								0				0
Reclassification of amortization of forward starting swap included in interest expense	0						0
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income	51,601			35,467		16,134	51,601									16,134	35,467
Conversion of operating partnership units (in shares)																-372,654	372,654
Conversion of operating partnership units																-7,096	7,096
Issuance of restricted units (in shares)																	10,015
Forfeiture of restricted units																	-2,253
Distributions							-48,452									-15,367	-33,085
Stock-based compensation							2,852										2,852
Shares, Outstanding		39,664,212
Partners' Capital at Dec. 31, 2012							685,729									47,368	638,361	0
Ending Balance at Dec. 31, 2012	685,729	397	663,589	-25,625	0	47,368
Partners' Capital Account, Units at Dec. 31, 2012																18,023,435	39,664,212
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	4,865						4,865
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income	4,865						4,865
Partners' Capital at Mar. 31, 2013
Partners' Capital at Dec. 31, 2012							685,729									47,368	638,361	0
Beginning Balance at Dec. 31, 2012	685,729	397	663,589	-25,625	0	47,368
Partners' Capital Account, Units at Dec. 31, 2012																18,023,435	39,664,212
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	22,594			15,756		6,838	22,594									6,838	15,756
Common shares issued (in shares)		741,452
Common shares issued	24,910	7	24,903
Conversion of operating partnership units (in shares)		106,326
Conversion of operating partnership units	0	1	859			-860
Issuance of restricted stock (in shares)		5,004
Issuance of restricted stock	0	0
Forfeiture of restricted stock (in shares)		-4,431
Forfeiture of restricted stock	0	0
Dividends declared and paid	-49,500			-34,221		-15,279
Stock-based compensation	2,845		2,845
Other comprehensive income (loss) unrealized gain (loss) on derivatives								0				0
Reclassification of amortization of forward starting swap included in interest expense	0						0
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income	22,594			15,756		6,838	22,594									6,838	15,756
Conversion of operating partnership units (in shares)																-106,326	106,326
Conversion of operating partnership units																-860	860
Issuance of restricted units (in shares)																	5,004
Forfeiture of restricted units																	-4,431
Distributions							-49,500									-15,279	-34,221
Stock-based compensation							2,845										2,845
Contributions from American Assets Trust, Inc. (in shares)																	741,452
Contributions from American Assets Trust, Inc.							24,910										24,910
Shares, Outstanding		40,512,563
Partners' Capital at Dec. 31, 2013							686,578									38,067	648,511
Ending Balance at Dec. 31, 2013	686,578	405	692,196	-44,090		38,067
Partners' Capital Account, Units at Dec. 31, 2013																17,917,109	40,512,563
Ending Balance (in shares) at Dec. 31, 2013	40,512,563
Partners' Capital at Sep. 30, 2013
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	6,907						6,907
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income	6,907						6,907
Partners' Capital at Dec. 31, 2013							686,578
Ending Balance at Dec. 31, 2013	686,578
Ending Balance (in shares) at Dec. 31, 2013	40,512,563
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	6,658						6,658
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income	6,658						6,658
Partners' Capital at Mar. 31, 2014
Partners' Capital at Dec. 31, 2013							686,578									38,067	648,511	0
Beginning Balance at Dec. 31, 2013	686,578	405	692,196	-44,090	0	38,067
Partners' Capital Account, Units at Dec. 31, 2013																17,917,109	40,512,563
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	31,145			22,130		9,015	31,145									9,015	22,130
Common shares issued (in shares)		3,110,067
Common shares issued	104,148	31	104,117
Conversion of operating partnership units (in shares)		11,852
Conversion of operating partnership units			-133			133
Issuance of restricted stock (in shares)		216,748
Issuance of restricted stock	0	2	-2
Forfeiture of restricted stock (in shares)		-1,192
Forfeiture of restricted stock	0	0
Dividends declared and paid	-54,311			-38,331		-15,980
Stock-based compensation	3,666		3,666
Shares withheld for employee taxes (in shares)		-148,369															148,369
Shares withheld for employee taxes	-4,780	-1	-4,779				4,780										4,780
Other comprehensive income (loss) unrealized gain (loss) on derivatives								-1,448	-1,024	-424	-1,448	1,617	1,144	473	1,617				-1,448	1,617
Reclassification of amortization of forward starting swap included in interest expense	-39				-28	-11	-39
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income	31,145			22,130		9,015	31,145									9,015	22,130
Conversion of operating partnership units (in shares)																-11,852	11,852
Conversion of operating partnership units																133	-133
Issuance of restricted units (in shares)																	216,748
Forfeiture of restricted units																	-1,192
Distributions							-54,311									-15,980	-38,331
Stock-based compensation							3,666										3,666
Contributions from American Assets Trust, Inc. (in shares)																	3,110,067
Contributions from American Assets Trust, Inc.							104,148										104,148
Reclassification of amortization of forward starting swap included in interest expense							-39											-39
Shares, Outstanding		43,701,669
Partners' Capital at Dec. 31, 2014							766,576									31,235	735,211	130
Ending Balance at Dec. 31, 2014	766,576	437	795,065	-60,291	92	31,273
Partners' Capital Account, Units at Dec. 31, 2014																17,905,257	43,701,669
Ending Balance (in shares) at Dec. 31, 2014	43,701,669
Partners' Capital at Sep. 30, 2014
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	10,046						10,046
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income	10,046						10,046
Partners' Capital at Dec. 31, 2014							766,576
Ending Balance at Dec. 31, 2014	$766,576
Ending Balance (in shares) at Dec. 31, 2014	43,701,669

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
OPERATING ACTIVITIES
Net income	$31,145	$22,594	$51,601
Results from discontinued operations	0	0	-37,652
Income from continuing operations	31,145	22,594	13,949
Adjustments to reconcile income from continuing operations to net cash provided by operating activities:
Deferred rent revenue and amortization of lease intangibles	-4,623	-4,997	-6,967
Depreciation and amortization	66,568	66,775	61,853
Amortization of debt issuance costs and debt fair value adjustments	4,075	3,932	3,911
Stock-based compensation expense	3,666	2,845	2,852
Settlement of forward interest rate swap agreement	1,617	0	0
Other noncash interest expense	-39	0	0
Other, net	-95	848	2,422
Changes in operating assets and liabilities
Change in restricted cash	1,198	-755	-1,000
Change in accounts receivable	279	-45	63
Change in other assets	-107	-88	143
Change in accounts payable and accrued expenses	1,381	1,167	-1,799
Change in security deposits payable	358	307	-50
Change in other liabilities and deferred credits	188	151	186
Net cash provided by operating activities of continuing operations	105,611	92,734	75,563
Net cash provided by operating activities of discontinued operations	0	0	382
Net cash provided by operating activities	105,611	92,734	75,945
INVESTING ACTIVITIES
Acquisition of real estate, net of cash acquired	0	0	-273,990
Capital expenditures	-144,674	-55,675	-34,582
Change in restricted cash, reserves for capital improvements	-3,068	453	2,557
Leasing commissions	-5,098	-3,032	-3,456
Maturity of marketable securities	0	0	4,384
Sale of marketable securities	0	0	23,191
Net cash used in investing activities of continuing operations	-152,840	-58,254	-281,896
Net cash provided by investing activities of discontinued operations	0	0	87,601
Net cash used in investing activities	-152,840	-58,254	-194,295
FINANCING ACTIVITIES
Change in restricted cash	0	-1,400	0
Issuance of secured notes payable	0	0	132,900
Repayment of secured notes payable	-142,276	-95,420	-34,626
Proceeds from term loan	100,000	0	0
Proceeds from unsecured line of credit	0	93,000	164,000
Repayment of unsecured line of credit	93,000	0	164,000
Proceeds from issuance of senior guaranteed notes payable	150,000	0	0
Debt issuance costs	-2,141	0	-1,355
Proceeds from issuance of common stock, net	104,107	25,348	0
Dividends paid to common stock and unitholders	-54,311	-49,500	-48,452
Deferred offering costs	0	0	-361
Shares withheld for employee taxes	-4,780	0	0
Net cash provided by (used in) financing activities	57,599	-27,972	48,106
Net (decrease) increase in cash and cash equivalents	10,370	6,508	-70,244
Cash and cash equivalents, beginning of period	48,987	42,479	112,723
Cash and cash equivalents, end of period	59,357	48,987	42,479
American Assets Trust, L.P.
OPERATING ACTIVITIES
Net income	31,145	22,594	51,601
Results from discontinued operations	0	0	-37,652
Income from continuing operations	31,145	22,594	13,949
Adjustments to reconcile income from continuing operations to net cash provided by operating activities:
Deferred rent revenue and amortization of lease intangibles	-4,623	-4,997	-6,967
Depreciation and amortization	66,568	66,775	61,853
Amortization of debt issuance costs and debt fair value adjustments	4,075	3,932	3,911
Stock-based compensation expense	3,666	2,845	2,852
Settlement of forward interest rate swap agreement	1,617	0	0
Other noncash interest expense	-39	0	0
Other, net	-95	848	2,422
Changes in operating assets and liabilities
Change in restricted cash	1,198	-755	-1,000
Change in accounts receivable	279	-45	63
Change in other assets	-107	-88	143
Change in accounts payable and accrued expenses	1,381	1,167	-1,799
Change in security deposits payable	358	307	-50
Change in other liabilities and deferred credits	188	151	186
Net cash provided by operating activities of continuing operations	105,611	92,734	75,563
Net cash provided by operating activities of discontinued operations	0	0	382
Net cash provided by operating activities	105,611	92,734	75,945
INVESTING ACTIVITIES
Acquisition of real estate, net of cash acquired	0	0	-273,990
Capital expenditures	-144,674	-55,675	-34,582
Change in restricted cash, reserves for capital improvements	-3,068	453	2,557
Leasing commissions	-5,098	-3,032	-3,456
Maturity of marketable securities	0	0	4,384
Sale of marketable securities	0	0	23,191
Net cash used in investing activities of continuing operations	-152,840	-58,254	-281,896
Net cash provided by investing activities of discontinued operations	0	0	87,601
Net cash used in investing activities	-152,840	-58,254	-194,295
FINANCING ACTIVITIES
Change in restricted cash	0	-1,400	0
Issuance of secured notes payable	0	0	132,900
Repayment of secured notes payable	-142,276	-95,420	-34,626
Proceeds from term loan	100,000	0	0
Proceeds from unsecured line of credit	0	93,000	164,000
Repayment of unsecured line of credit	93,000	0	164,000
Proceeds from issuance of senior guaranteed notes payable	150,000	0	0
Debt issuance costs	-2,141	0	-1,355
Proceeds from issuance of common stock, net	104,107	25,348	0
Dividends paid to common stock and unitholders	-54,311	-49,500	-48,452
Deferred offering costs	0	0	-361
Shares withheld for employee taxes	-4,780	0	0
Net cash provided by (used in) financing activities	57,599	-27,972	48,106
Net (decrease) increase in cash and cash equivalents	10,370	6,508	-70,244
Cash and cash equivalents, beginning of period	48,987	42,479	112,723
Cash and cash equivalents, end of period	$59,357	$48,987	$42,479

Summary_of_Significant_Account

Summary of Significant Accounting Policies (Notes)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
	Business and Organization
	American Assets Trust, Inc. (which may be referred to in these financial statements as the “company,” “we,” “us,” or “our”) is a Maryland corporation formed on July 16, 2010 that did not have any operating activity until the consummation of our initial public offering (the “Offering”) and the related acquisition on January 19, 2011 of certain assets of a combination of entities whose assets included entities owned and/or controlled by Ernest S. Rady and his affiliates, including the Rady Trust, which in turn owned (1) controlling interests in entities owning 17 properties and the property management business of American Assets, Inc. and (2) noncontrolling interests in entities owning four properties. The company is the sole general partner of American Assets Trust, L.P., a Maryland limited partnership formed on July 16, 2010 (the “Operating Partnership”). The company's operations are carried on through our Operating Partnership and its subsidiaries, including our taxable REIT subsidiary. Since the formation of our Operating Partnership, the company has controlled our Operating Partnership as its general partner and has consolidated its assets, liabilities and results of operations.
	We are a vertically integrated and self-administered REIT with 113 employees providing substantial in-house expertise in asset management, property management, property development, leasing, tenant improvement construction, acquisitions, repositioning, redevelopment and financing.
	Any reference to the number of properties or units and square footage or acres are unaudited and outside the scope of our independent registered public accounting firm's audit of our financial statements in accordance with the standards of the United States Public Company Accounting Oversight Board.
	As of December 31, 2014, we owned or had a controlling interest in 23 office, retail, multifamily and mixed-use operating properties, the operations of which we consolidate. Additionally, as of December 31, 2014, we owned land at five of our properties that we classify as held for development and construction in progress. A summary of the properties owned by us is as follows:
	Retail
	Carmel Country Plaza	Del Monte Center
	Carmel Mountain Plaza	Geary Marketplace
	South Bay Marketplace	The Shops at Kalakaua
	Rancho Carmel Plaza	Waikele Center
	Lomas Santa Fe Plaza	Alamo Quarry Market
	Solana Beach Towne Centre
	Office
	Torrey Reserve Campus	Lloyd District Portfolio
	Solana Beach Corporate Centre	City Center Bellevue
	The Landmark at One Market
	One Beach Street
	First & Main
	Multifamily
	Loma Palisades
	Imperial Beach Gardens
	Mariner's Point
	Santa Fe Park RV Resort
	Mixed-Use
	Waikiki Beach Walk Retail and Embassy Suites™ Hotel
	Held for Development and Construction in Progress
	Solana Beach Corporate Centre – Land
	Solana Beach – Highway 101 – Land
	Sorrento Pointe – Land
	Torrey Reserve – Construction in Progress
	Lloyd District Portfolio – Construction in Progress
	Basis of Presentation
	Our consolidated financial statements include the accounts of the company, our Operating Partnership and our subsidiaries. The equity interests of other investors in our Operating Partnership are reflected as noncontrolling interests.
	All significant intercompany transactions and balances are eliminated in consolidation.
	Use of Estimates
	The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America, referred to as “GAAP,” requires management to make estimates and assumptions that in certain circumstances affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities, and revenues and expenses. These estimates are prepared using management's best judgment, after considering past, current and expected events and economic conditions. Actual results could differ from these estimates.
	Consolidated Statements of Cash Flows-Supplemental Disclosures
	The following table provides supplemental disclosures related to the Consolidated Statements of Cash Flows (in thousands):
		Year Ended December 31,
		2014		2013		2012
	Supplemental cash flow information
	Total interest costs incurred	$	58,455	$	60,133	$	58,074
	Interest capitalized	$	5,490	$	2,113	$	746
	Interest expense	$	52,965	$	58,020	$	57,328
	Cash paid for interest, net of amounts capitalized (including discontinued operations)	$	48,032	$	54,345	$	55,349
	Cash paid for income taxes	$	404	$	901	$	1,239
	Supplemental schedule of noncash investing and financing activities
	Accounts payable and accrued liabilities for construction in progress	$	9,908	$	5,001	$	4,944
	Accrued leasing commissions	$	763	$	1,385	$	(782	)
	Accrued placement fees for senior guaranteed notes payable	$	750	$	—	$	—
	Reduction to capital for prepaid equity financing costs	$	40	$	437	$	—
	Revenue Recognition and Accounts Receivable
	Our leases with tenants are classified as operating leases. Substantially all such leases contain fixed rent escalations which occur at specified times during the term of the lease. Base rents are recognized on a straight-line basis from when the tenant controls the space through the term of the related lease, net of valuation adjustments, based on management's assessment of credit, collection and other business risks. When we determine that we are the owner of tenant improvements and the tenant has reimbursed us for a portion or all of the tenant improvement costs, we consider the amount paid to be additional rent, which is recognized on a straight-line basis over the term of the related lease. For first generation tenants, in instances in which we fund tenant improvements and the improvements are deemed to be owned by us, revenue recognition will commence when the improvements are substantially completed and possession or control of the space is turned over to the tenant. When we determine that the tenant is the owner of tenant improvements, tenant allowances are recorded as lease incentives and we commence revenue recognition and lease incentive amortization when possession or control of the space is turned over to the tenant for tenant work to begin. Percentage rents, which represent additional rents based upon the level of sales achieved by certain tenants, are recognized at the end of the lease year or earlier if we have determined the required sales level is achieved and the percentage rents are collectible. Real estate tax and other cost reimbursements are recognized on an accrual basis over the periods in which the related expenditures are incurred.
	Other property income includes parking income, general excise tax billed to tenants and fees charged to tenants at our multifamily properties. Other property income is recognized when earned. We recognize general excise tax gross, with the amounts billed to tenants and customers recorded in other property income and the related taxes paid as rental expense. The general excise tax included in other income was $3.4 million, $3.5 million and $3.3 million for the years ended December 31, 2014, 2013 and 2012, respectively. For a tenant to terminate its lease agreement prior to the end of the agreed term, we may require that they pay a fee to cancel the lease agreement. Lease termination fees for which the tenant has relinquished control of the space are generally recognized on the termination date. When a lease is terminated early but the tenant continues to control the space under a modified lease agreement, the lease termination fee is generally recognized evenly over the remaining term of the modified lease agreement.
	We recognize revenue on the hotel portion of our mixed-use property from the rental of hotel rooms and guest services when the rooms are occupied and services have been provided. Food and beverage sales are recognized when the customer has been served or at the time the transaction occurs. Revenue from room rental is included in rental revenue on the statement of income. Revenue from other sales and services provided is included in other property income on the statement of income.
	We make estimates of the collectability of our accounts receivable related to minimum rents, straight-line rents, expense reimbursements and other revenue. Accounts receivable and deferred rent receivable are carried net of this allowance for doubtful accounts. We generally do not require collateral or other security from our tenants, other than letters of credit or security deposits. Our determination as to the collectability of accounts receivable and correspondingly, the adequacy of this allowance, is based primarily upon evaluations of individual receivables, current economic conditions, historical experience and other relevant factors. The allowance for doubtful accounts is increased or decreased through bad debt expense. In some cases, primarily relating to straight-line rents, the collection of these amounts extends beyond one year. Our experience relative to unbilled straight-line rents is that a portion of the amounts otherwise recognizable as revenue is never billed to or collected from tenants due to early lease terminations, lease modifications, bankruptcies and other factors. Accordingly, the extended collection period for straight-line rents along with our evaluation of tenant credit risk may result in the nonrecognition of a portion of straight-line rental income until the collection of such income is reasonably assured. If our evaluation of tenant credit risk changes indicating more straight-line revenue is reasonably collectible than previously estimated and realized, the additional straight-line rental income is recognized as revenue. If our evaluation of tenant credit risk changes indicating a portion of realized straight-line rental income is no longer collectible, a reserve and bad debt expense is recorded. At December 31, 2014 and December 31, 2013, our allowance for doubtful accounts was $0.8 million and $1.0 million, respectively, and our allowance for deferred rent receivables was $1.2 million and $1.2 million, respectively. Total bad debt expense was $0.2 million, $0.1 million and $0.6 million for the years ended December 31, 2014, 2013 and 2012, respectively.
	We recognize gains on sales of properties upon the closing of the transaction with the purchaser. Gains on properties sold are recognized using the full accrual method when (1) the collectability of the sales price is reasonably assured, (2) we are not obligated to perform significant activities after the sale, (3) the initial investment from the buyer is sufficient and (4) other profit recognition criteria have been satisfied. Gains on sales of properties may be deferred in whole or in part until the requirements for gain recognition have been met.
	Real Estate
	Land, buildings and improvements are recorded at cost. Depreciation is computed using the straight-line method. Estimated useful lives range generally from 30 years to a maximum of 40 years on buildings and major improvements. Minor improvements, furniture and equipment are capitalized and depreciated over useful lives ranging from 3 years to 15 years. Maintenance and repairs that do not improve or extend the useful lives of the related assets are charged to operations as incurred. Tenant improvements are capitalized and depreciated over the life of the related lease or their estimated useful life, whichever is shorter. If a tenant vacates its space prior to the contractual termination of its lease, the undepreciated balance of any tenant improvements are written off if they are replaced or have no future value. For the years ended December 31, 2014, 2013 and 2012, real estate depreciation expense was $56.0 million, $52.0 million and $47.8 million, respectively, including amounts from discontinued operations.
	Acquisitions of properties are accounted for in accordance with the authoritative accounting guidance on acquisitions and business combinations. Our methodology of allocating the cost of acquisitions to assets acquired and liabilities assumed is based on estimated fair values, replacement cost and appraised values. When we acquire operating real estate properties, the purchase price is allocated to land and buildings, intangibles such as in-place leases, and to current assets and liabilities acquired, if any. Such valuations include a consideration of the noncancelable terms of the respective leases as well as any applicable renewal periods. The fair values associated with below market renewal options are determined based on a review of several qualitative and quantitative factors on a lease-by-lease basis at acquisition to determine whether it is probable that the tenant would exercise its option to renew the lease agreement. These factors include: (1) the type of tenant in relation to the property it occupies, (2) the quality of the tenant, including the tenant's long term business prospects and (3) whether the fixed rate renewal option was sufficiently lower than the fair rental of the property at the date the option becomes exercisable such that it would appear to be reasonably assured that the tenant would exercise the option to renew. The value allocated to in-place leases is amortized over the related lease term and reflected as depreciation and amortization in the statement of income.
	The value of above and below market leases associated with the original noncancelable lease terms are amortized to rental income over the terms of the respective noncancelable lease periods and are reflected as either an increase (for below market leases) or a decrease (for above market leases) to rental income in the statement of income. The value of the leases associated with below market lease renewal options that are likely to be exercised are amortized to rental income over the respective renewal periods. If a tenant vacates its space prior to contractual termination of its lease or the lease is not renewed, the unamortized balance of any in-place lease value is written off to rental income and amortization expense. Acquisition-related expenses are expensed in the period incurred.
	Capitalized Costs
	We capitalize certain costs related to the development and redevelopment of real estate including pre-construction costs, real estate taxes, insurance and construction costs and salaries and related costs of personnel directly involved. Additionally, we capitalize interest costs related to development and significant redevelopment activities. Capitalization of these costs begins when the activities and related expenditures commence and cease when the project is substantially complete and ready for its intended use, at which time the project is placed in service and depreciation commences. Additionally, we make estimates as to the probability of certain development and redevelopment projects being completed. If we determine that the completion of development or redevelopment is no longer probable, we expense all capitalized costs which are not recoverable.
Impairment of Long Lived Assets
We review for impairment on a property by property basis. Impairment is recognized on properties held for use when the expected undiscounted cash flows for a property are less than its carrying amount at which time the property is written-down to fair value. Properties held for sale are recorded at the lower of the carrying amount or the expected sales price less costs to sell.
Financial Instruments
The estimated fair values of financial instruments are determined using available market information and appropriate valuation methods. Considerable judgment is necessary to interpret market data and develop estimated fair values. The use of different market assumptions or estimation methods may have a material effect on the estimated fair value amounts. Accordingly, estimated fair values are not necessarily indicative of the amounts that could be realized in current market exchanges.
Derivative Instruments
At times, we may use derivative instruments to manage exposure to variable interest rate risk. We may enter into interest rate swaps to manage our exposure to variable interest rate risk. If and when we enter into derivative instruments, we ensure that such instruments qualify as cash flow hedges and would not enter into derivative instruments for speculative purposes.
Any interest rate swaps associated with our cash flow hedges are recorded at fair value on a recurring basis. We assess effectiveness of our cash flow hedges both at inception and on an ongoing basis. The effective portion of changes in fair value of the interest rate swaps associated with our cash flow hedges is recorded in accumulated other comprehensive income (loss) and is subsequently reclassified into interest expense as interest is incurred on the related variable rate debt. Our cash flow hedges become ineffective if critical terms of the hedging instrument and the debt instrument do not perfectly match such as notional amounts, settlement dates, reset dates, calculation period and LIBOR rate. In addition, we evaluate the default risk of the counterparty by monitoring the credit worthiness of the counterparty. When ineffectiveness exists, the ineffective portion of changes in fair value of the interest rate swaps associated with our cash flow hedges is recognized in earnings in the period affected. We had no hedging instruments outstanding during 2013 or 2012. Concurrent with the closing of the amended and restated credit facility, we entered into an interest rate swap agreement that is intended to fix the interest rate associated with the term loan at approximately 3.08% through its maturity date and extension options, subject to adjustments based on our consolidated leverage ratio (see Note 9).
Cash and Cash Equivalents
We define cash and cash equivalents as cash on hand, demand deposits with financial institutions and short term liquid investments with an initial maturity of less than 3 months. Cash balances in individual banks may exceed the federally insured limit of $250,000 by the Federal Deposit Insurance Corporation (the "FDIC"). No losses have been experienced related to such accounts. At December 31, 2014 and December 31, 2013, we had $32.4 million and $29.0 million, respectively, in excess of the FDIC insured limit. At December 31, 2014 and December 31, 2013, we had $20.0 million and $11.0 million, respectively, in money market funds that are not FDIC insured.
Restricted Cash
Restricted cash consists of amounts held by lenders to provide for future real estate tax expenditures, insurance expenditures and reserves for capital improvements. Activity for accounts related to real estate tax and insurance expenditures is classified as operating activities in the statement of cash flows. Changes in reserves for capital improvements are classified as investing activities in the statement of cash flows. At December 31, 2014 and 2013, we had $11.0 million and $9.1 million, respectively, in restricted cash.
Marketable Securities
Our portfolio of marketable securities was comprised of debt securities that are classified as trading. Trading securities are presented on our consolidated balance sheets at fair value at the end of each reporting period. Gains and losses resulting from the mark-to-market of these securities were recognized as unrealized and realized gains or losses in income.
Other Assets
Other assets consist primarily of lease costs, lease incentives, acquired in-place leases, acquired above market leases and debt issuance costs. Capitalized lease costs are direct costs incurred which were essential to originate a lease and would not have been incurred had the leasing transaction not taken place and include third party commissions related to obtaining a lease. Capitalized lease costs are amortized over the life of the related lease and included in depreciation and amortization expense on the statement of income. If a tenant vacates its space prior to the contractual termination of its lease, the unamortized balance of any lease costs are written off. We view these lease costs as part of the up-front initial investment we made in order to generate a long-term cash inflow. Therefore, we classify cash outflows for lease costs as an investing activity in our consolidated statements of cash flows.
Costs related to the issuance of debt instruments are capitalized and are amortized as interest expense over the estimated life of the related issue using the straight-line method which approximates the effective interest method. If a debt instrument is paid off prior to its original maturity date, the unamortized balance of debt issuance costs are written off to interest expense or, if significant, included in “early extinguishment of debt.” For the years ended December 31, 2014, 2013 and 2012 there were no early extinguishments of debt or write offs of debt issuance costs.
Variable Interest Entities
Certain entities that do not have sufficient equity at risk for the entity to finance its activities without additional subordinated financial support from other parties or in which equity investors do not have the characteristics of a controlling financial interest qualify as variable interest entities (“VIEs”). VIEs are required to be consolidated by their primary beneficiary. The primary beneficiary of a VIE is the party that has a controlling interest in the VIE. Identifying the party with the controlling interest requires a focus on which entity has the power to direct the activities of the VIE that most significantly impact the VIE's economic performance and (1) the obligation to absorb the expected losses of the VIE or (2) the right to receive the benefits from the VIE. At December 31, 2014 we have no investments in real estate joint ventures and, accordingly we have no VEIs which need to be consolidated.
Stock-Based Compensation
We grant stock-based compensation awards to our employees and directors typically in the form of restricted shares of common stock, options to purchase common stock and/or shares of common stock. We measure stock-based compensation expense based on the fair value of the award on the grant date and recognize the expense ratably over the vesting period.
Deferred Compensation
Our Operating Partnership has adopted the American Assets Trust Executive Deferral Plan V (“EDP V”) and the American Assets Trust Executive Deferral Plan VI (“EDP VI”). These plans were adopted by our Operating Partnership as successor plans to those deferred compensation plans maintained by American Assets Inc. ("AAI") in which certain employees of AAI, who were transferred to us in connection with the Offering (the “Transferred Participants”), participated prior to the Offering. EDP V and EDP VI contain substantially the same terms and conditions as these predecessor plans. AAI transferred to our Operating Partnership the Transferred Participants' account balances under the predecessor plans. These transferred account balances represent amounts deferred by the Transferred Participants prior to the Offering while they were employed by AAI.
At the time eligible participants defer compensation, we record compensation cost and a corresponding deferred compensation plan liability, which is included in other liabilities and deferred credits on our consolidated balance sheets. This liability is adjusted to fair value at the end of each accounting period based on the performance of the benchmark funds selected by each participant, and the impact of adjusting the liability to fair value is recorded as an increase or decrease to compensation cost.
Income Taxes
We elected to be taxed as a REIT under the Internal Revenue Code of 1986, as amended (the “Code”) commencing with the taxable year ending December 31, 2011. To maintain our qualification as a REIT, we are required to distribute at least 90% of our REIT taxable income to our stockholders and meet the various other requirements imposed by the Code relating to such matters as operating results, asset holdings, distribution levels and diversity of stock ownership. Provided we maintain our qualification for taxation as a REIT, we are generally not subject to corporate level income tax on the earnings distributed currently to our stockholders that we derive from our REIT qualifying activities. If we fail to maintain our qualification as a REIT in any taxable year, and are unable to avail ourselves of certain savings provisions set forth in the Code, all of our taxable income would be subject to federal income tax at regular corporate rates, including any applicable alternative minimum tax. We are subject to certain state and local income taxes.
We, together with one of our subsidiaries, have elected to treat such subsidiary as a taxable REIT subsidiary (a “TRS”) for federal income tax purposes. Certain activities that we undertake must be conducted by a TRS, such as non-customary services for our tenants, and holding assets that we cannot hold directly. A TRS is subject to federal and state income taxes.
Segment Information
Segment information is prepared on the same basis that our management reviews information for operational decision-making purposes. We operate in four business segments: the acquisition, redevelopment, ownership and management of retail real estate, office real estate, multifamily real estate and mixed-use real estate. The products for our retail segment primarily include rental of retail space and other tenant services, including tenant reimbursements, parking and storage space rental. The products for our office segment primarily include rental of office space and other tenant services, including tenant reimbursements, parking and storage space rental. The products for our multifamily segment include rental of apartments and other tenant services. The products of our mixed-use segment include rental of retail space and other tenant services, including tenant reimbursements, parking and storage space rental and operation of a 369-room all-suite hotel.
Recent Accounting Pronouncements
In February 2013, the FASB issued ASU 2013-2, Comprehensive Income (Topic 220): Reporting Amounts Reclassified Out of Accumulated Other Comprehensive Income. ASU 2013-2 requires entities to disclose certain information relating to amounts reclassified out of accumulated other comprehensive income. This pronouncement became effective for us in the first quarter of 2013 and did not have a significant impact on our consolidated financial statements.
In April 2014, the FASB issued ASU 2014-08, Presentation of Financial Statements (Topic 205) and Property, Plant, and Equipment (Topic 360): Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity. ASU 2014-08 revises the definition of a discontinued operation to a disposal, sale or held-for-sale component or group of components that represents a strategic shift that will have a major effect on an entity's operations and financial results. This pronouncement is effective in 2015, however, calendar year-end companies may early adopt during the first quarter of 2014. We have chosen to early adopt this pronouncement and it became effective for us in the first quarter of 2014. This pronouncement did not have a significant impact on our consolidated financial statements.
In May 2014, the FASB issued Update No. 2014-09, Revenue from Contracts with Customers. Update No. 2014-09 establishes that companies may recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. This pronouncement is effective for annual reporting periods beginning after December 15, 2016, including interim reporting periods within that reporting period; early adoption is not permitted. We are in the process of evaluating the impact this pronouncement will have on our consolidated financial statements.

Real_Estate_Notes

Real Estate (Notes)	12 Months Ended
	Dec. 31, 2014
Real Estate [Abstract]
REAL ESTATE	REAL ESTATE
	A summary of our real estate investments is as follows (in thousands):
		Retail			Office			Multifamily			Mixed-Use			Total
	December 31, 2014
	Land	$	248,386		$	143,575		$	25,507		$	76,635		$	494,103
	Buildings	500,088			621,343			42,270			125,798			1,289,499
	Land improvements	39,999			8,273			3,085			2,363			53,720
	Tenant improvements	50,504			56,127			—			1,679			108,310
	Furniture, fixtures, and equipment	491			750			5,832			5,383			12,456
	Construction in progress	5,327			31,878			141,205			326			178,736			(1)
		844,795			861,946			217,899			212,184			2,136,824
	Accumulated depreciation	(205,339		)	(104,092		)	(35,431		)	(16,562		)	(361,424		)
	Net real estate	$	639,456		$	757,854		$	182,468		$	195,622		$	1,775,400
	December 31, 2013
	Land	$	248,008		$	143,575		$	25,507		$	76,635		$	493,725
	Buildings	499,091			618,077			42,270			123,142			1,282,580
	Land improvements	39,892			7,528			3,010			2,363			52,793
	Tenant improvements	46,649			51,016			—			1,697			99,362
	Furniture, fixtures, and equipment	489			517			5,482			10,080			16,568
	Construction in progress	2,673			14,189			32,252			1,275			50,389			(1)
		836,802			834,902			108,521			215,192			1,995,417
	Accumulated depreciation	(185,095		)	(84,012		)	(33,909		)	(15,565		)	(318,581		)
	Net real estate	$	651,707		$	750,890		$	74,612		$	199,627		$	1,676,836
	(1) Land related to held for development and construction in progress is included in the Held for Development and Construction in Progress classifications on the consolidated balance sheets.
	Acquisitions
	2012 Acquisitions
	On January 24, 2012, we acquired One Beach Street, consisting of approximately 97,000 square feet in a three-story fully renovated historic office building located along the Embarcadero in San Francisco's North Waterfront District. The purchase price was approximately $36.5 million, excluding closing costs of approximately $0.02 million, which are included in other income (expense), net on the statement of income. The identified intangible assets and liabilities are being amortized over a weighted average life of 7.0 years.
	On August 21, 2012, we acquired City Center Bellevue, a 27-story LEED-EB Gold certified office tower, consisting of approximately 497,000 square feet, located in Bellevue, Washington. The purchase price was approximately $228.8 million, excluding closing costs of approximately $0.1 million, which are included in other income (expense), net on the statement of income. Additionally, we received credits to our purchase price of approximately $6.9 million that primarily relate to outstanding tenant improvement obligations and rent abatements. The identified intangible assets and liabilities are being amortized over a weighted average life of 5.8 years.
	On December 19, 2012, we acquired Geary Marketplace, a newly constructed, approximately 35,000 square foot, 100% leased, grocery-anchored shopping center in Walnut Creek, California.  The purchase price was approximately $21.0 million, excluding closing costs of approximately $0.02 million, which are included in other income (expense), net on the statement of income. The identified intangible assets and liabilities are being amortized over a weighted average life of 19.8 years.
	The fair values assigned to identifiable intangible assets acquired were based on estimates and assumptions determined by management. Using information available at the time the acquisition closed, we allocated the total consideration to tangible assets and liabilities and identified intangible assets and liabilities. The allocation of the purchase price for each of One Beach Street, City Center Bellevue and Geary Marketplace is as follows (in thousands):
		One Beach Street			City Center Bellevue			Geary Marketplace			Total
	Land	$	15,332		$	25,135		$	8,239		$	48,706
	Building	16,764			185,653			11,179			213,596
	Land improvements	30			154			704			888
	Tenant improvements	1,223			5,191			470			6,884
	Total real estate	33,349			216,133			20,592			270,074
	Lease intangibles	4,141			11,870			1,017			17,028
	Prepaid expenses and other assets	1			2,596			414			3,011
	Total assets	$	37,491		$	230,599		$	22,023		$	290,113
	Accounts payable and accrued expenses	$	94		$	456		$	—		$	550
	Security deposits payable	75			740			—			815
	Lease intangibles	1,382			8,733			1,124			11,239
	Other liabilities and deferred credits	22			497			—			519
	Total liabilities	$	1,573		$	10,426		$	1,124		$	13,123
	We have included the results of operations for One Beach Street, City Center Bellevue and Geary Marketplace in our consolidated statements of income from the date of acquisition. For the period of acquisition through December 31, 2012, One Beach Street contributed $3.9 million to total revenue, $1.0 million to operating expenses, $2.9 million to operating income and $0.6 million to net income. For the period of acquisition through December 31, 2012, City Center Bellevue contributed $7.0 million to total revenue, $1.6 million to operating expenses, $5.4 million to operating income and an insignificant amount to net income. For the period of acquisition through December 31, 2012, Geary Marketplace contributed an insignificant amount to total revenue, expenses, operating income and net income.
	Dispositions
	On December 4, 2012, we sold 160 King Street for a sales price of approximately $93.8 million. The property is located in San Francisco, California and was previously included in our office segment. The decision to sell 160 King Street was a result of our desire to focus resources on our core, high-barrier-to-entry markets. The sale was completed as a reverse tax deferred exchange in conjunction with the acquisition of City Center Bellevue pursuant to the provisions of Section 1031 of the Code and applicable state revenue and taxation code sections. As a result of the sale, 160 King Street no longer serves as a borrowing base property under our amended and restated credit facility.
	We determined that 160 King Street became a discontinued operation in the fourth quarter of 2012. We have, therefore, classified 160 King Street's net assets, liabilities and operating results as discontinued operations on our balance sheets and our statements of income for all periods prior to the sale.
	Net revenue and net income from the property's discontinued operations were as follows (in thousands):
		Year Ended December 31,
		2014			2013			2012
	Net revenue from discontinued operations	$	—		$	—		$	6,734
	Results from discontinued operations
	Income from discontinued operations	—			—			932
	Gain on sale of real estate from discontinued operations	—			—			36,720
	Total income from discontinued operations	$	—		$	—		$	37,652

Acquired_InPlace_Leases_and_Ab

Acquired In-Place Leases and Above/Below Market Leases (Notes)	12 Months Ended
	Dec. 31, 2014
Leases [Abstract]
ACQUIRED IN-PLACE LEASES AND ABOVE/BELOW MARKET LEASES	ACQUIRED IN-PLACE LEASES AND ABOVE/BELOW MARKET LEASES
	The following summarizes our acquired lease intangibles, which are included in other assets and other liabilities and deferred credits (in thousands):
		December 31, 2014			December 31, 2013
	In-place leases	$	53,967		$	62,813
	Accumulated amortization	(35,336		)	(38,279		)
	Above market leases	22,500			28,279
	Accumulated amortization	(17,397		)	(20,880		)
	Acquired lease intangible assets, net	$	23,734		$	31,933
	Below market leases	$	70,013		$	76,502
	Accumulated accretion	(27,161		)	(28,592		)
	Acquired lease intangible liabilities, net	$	42,852		$	47,910
	The value allocated to in-place leases is amortized over the related lease term as depreciation and amortization expense in the statement of income. Above and below market leases are amortized over the related lease term as additional rental income for below market leases or a reduction of rental income for above market leases in the statement of income. Rental income (loss) includes net amortization from acquired above and below market leases of $2.8 million, $2.4 million and $(0.2) million in 2014, 2013 and 2012, respectively. The remaining weighted-average amortization period as of December 31, 2014, is 2.4 years, 1.4 years and 8.5 years for in-place leases, above market leases and below market leases, respectively. Below market leases include $17.5 million related to below market renewal options, and the weighted-average period prior to the commencement of the renewal options is 10.8 years.
	Increases (decreases) in net income as a result of amortization of our in-place leases, above market leases and below market leases are as follows (in thousands):
		Year Ended December 31,
		2014			2013			2012
	Amortization of in-place leases	$	(5,903	)	$	(9,120	)	$	(10,248	)
	Amortization of above market leases	(2,296		)	(4,052		)	(5,739		)
	Amortization of below market leases	5,057			6,440			5,502
	Net loss	$	(3,142	)	$	(6,732	)	$	(10,485	)
	As of December 31, 2014, the amortization for acquired leases during the next five years and thereafter, assuming no early lease terminations, is as follows (in thousands):
		In-Place			Above Market			Below Market
		Leases			Leases			Leases
	Year Ending December 31,
	2015	$	4,744		$	1,752		$	4,667
	2016	3,954			1,263			4,525
	2017	3,189			932			4,169
	2018	1,893			628			3,649
	2019	1,452			318			3,560
	Thereafter	3,399			210			22,282
		$	18,631		$	5,103		$	42,852

Marketable_Securities_Notes

Marketable Securities (Notes)	12 Months Ended
	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
MARKETABLE SECURITIES	MARKETABLE SECURITIES
	Our portfolio of marketable securities was comprised of debt securities that were classified as trading securities. Our marketable securities consisted of investments in mortgage-backed securities issued by the Government National Mortgage Association (“GNMA securities”). We reported our trading securities at fair value, using prices provided by independent market participants that are based on observable inputs using market-based valuation techniques (Level 2 of the fair value hierarchy-see Note 5). On August 20, 2012, we sold all of our outstanding GNMA securities with a realized loss of $0.7 million for the year ended December 31, 2012.

Fair_Value_of_Financial_Instru

Fair Value of Financial Instruments (Notes)	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
FAIR VALUE OF FINANCIAL INSTRUMENTS	FAIR VALUE OF FINANCIAL INSTRUMENTS
	A fair value measurement is based on the assumptions that market participants would use in pricing an asset or liability. The hierarchy for inputs used in measuring fair value is as follows:
	1	Level 1 Inputs—quoted prices in active markets for identical assets or liabilities
	2	Level 2 Inputs—observable inputs other than quoted prices in active markets for identical assets and liabilities
	3	Level 3 Inputs—unobservable inputs
	In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, for disclosure purposes, the level within which the fair value measurement is categorized is based on the lowest level input that is significant to the fair value measurement.
	Except as disclosed below, the carrying amount of our financial instruments approximates their fair value. Financial assets and liabilities whose fair values we measure on a recurring basis using Level 2 inputs consist of our deferred compensation liability and interest rate swap liability. We measure the fair values of these liabilities based on prices provided by independent market participants that are based on observable inputs using market-based valuation techniques provided by third parties using proprietary valuation models and analytical tools as of December 31, 2014 and 2013. These valuation models and analytical tools use market pricing or similar instruments that are both objective and publicly available, including matrix pricing or reported trades, benchmark yields, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids and/or offers.
	A summary of our financial liabilities that are measured at fair value on a recurring basis by level within the fair value hierarchy is as follows (in thousands):
		December 31, 2014											December 31, 2013
		Level 1		Level 2			Level 3			Total			Level 1		Level 2		Level 3		Total
	Deferred compensation liability	$	—	$	981		$	—		$	981		$	—	$	769	$	—	$	769
	Interest rate swap liability	$	—	$	1,448		$	—		$	1,448		$	—	$	—	$	—	$	—
	The fair value of our secured notes payable and unsecured notes payable is sensitive to fluctuations in interest rates. Discounted cash flow analysis (Level 2) is generally used to estimate the fair value of our mortgages and notes payable, using rates ranging from 3.6% to 5.7%.
	Considerable judgment is necessary to estimate the fair value of financial instruments. The estimates of fair value presented herein are not necessarily indicative of the amounts that could be realized upon disposition of the financial instruments. The carrying values of our line of credit and term loan set forth below are deemed to be at fair value since the outstanding debt is directly tied to monthly LIBOR contracts. A summary of the carrying amount and fair value of our financial instruments, all of which are based on Level 2 inputs, is as follows (in thousands):
		December 31, 2014							December 31, 2013
		Carrying Value			Fair Value				Carrying Value			Fair Value
	Secured notes payable	$	812,811		$	850,475			$	952,174		$	990,296
	Term loan	$	100,000		$	100,000			$	—		$	—
	Senior guaranteed notes, Series A	$	150,000		$	154,560			$	—		$	—
	Line of credit	$	—		$	—			$	93,000		$	93,000

Other_Assets_Notes

Other Assets (Notes)	12 Months Ended
	Dec. 31, 2014
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
OTHER ASSETS	OTHER ASSETS
	Other assets consist of the following (in thousands):
		31-Dec-14		31-Dec-13
	Leasing commissions, net of accumulated amortization of $20,659 and $19,606 respectively	$	19,484	$	18,071
	Acquired above market leases, net	5,103		7,399
	Acquired in-place leases, net	18,631		24,534
	Lease incentives, net of accumulated amortization of $2,960 and $2,590, respectively	740		1,110
	Other intangible assets, net of accumulated amortization of $1,590 and $1,554, respectively	453		655
	Debt issuance costs, net of accumulated amortization of $4,147 and $2,985, respectively	5,361		2,632
	Prepaid expenses, deposits and other	3,629		3,269
	Total other assets	$	53,401	$	57,670
	Lease incentives are amortized over the term of the related lease and included as a reduction of rental income in the statement of income.

Other_Liabilities_and_Deferred

Other Liabilities and Deferred Credits (Notes)	12 Months Ended
	Dec. 31, 2014
Other Liabilities Disclosure [Abstract]
OTHER LIABILITIES AND DEFERRED CREDITS	OTHER LIABILITIES AND DEFERRED CREDITS
	Other liabilities and deferred credits consist of the following (in thousands):
		31-Dec-14		31-Dec-13
	Acquired below market leases, net	$	42,852	$	47,910
	Prepaid rent and deferred revenue	7,288		7,506
	Interest rate swap liability	1,448		—
	Straight-line rent liability	2,533		1,145
	Deferred rent expense	584		829
	Deferred compensation	981		769
	Deferred tax liability	219		233
	Other liabilities	88		73
	Total other liabilities and deferred credits	$	55,993	$	58,465
	Straight-line rent liability relates to leases which have rental payments that decrease over time or one-time upfront payments for which the rental revenue is deferred and recognized on a straight-line basis.

Debt_Notes

Debt (Notes)	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
DEBT	DEBT
	Debt of American Assets Trust, Inc.
	American Assets Trust, Inc. does not hold any indebtedness. All debt is held directly or indirectly by the Operating Partnership; however, American Assets Trust, Inc. has guaranteed the Operating Partnership's amended and restated credit facility, term loan and carve-out guarantees on property-level debt.
	Debt of American Assets Trust, L.P.
	Secured notes payable
	The following is a summary of the Operating Partnership's total secured notes payable outstanding as of December 31, 2014 and December 31, 2013 (in thousands):
	Description of Debt	Principal Balance as of						Stated Interest Rate			Stated Maturity Date
		31-Dec-14			31-Dec-13			as of December 31, 2014
	Waikele Center (1)(2)	—			140,700			—			November 1, 2014
	The Shops at Kalakaua (1)(3)	19,000			19,000			5.45	%		May 1, 2015
	The Landmark at One Market (1)(5)	133,000			133,000			5.61	%		July 5, 2015
	Del Monte Center (1)(4)	82,300			82,300			4.93	%		July 8, 2015
	First & Main (1)	84,500			84,500			3.97	%		July 1, 2016
	Imperial Beach Gardens (1)	20,000			20,000			6.16	%		September 1, 2016
	Mariner’s Point (1)	7,700			7,700			6.09	%		September 1, 2016
	South Bay Marketplace (1)	23,000			23,000			5.48	%		February 10, 2017
	Waikiki Beach Walk—Retail (1)	130,310			130,310			5.39	%		July 1, 2017
	Solana Beach Corporate Centre III-IV (6)	36,376			36,804			6.39	%		August 1, 2017
	Loma Palisades (1)	73,744			73,744			6.09	%		July 1, 2018
	One Beach Street (1)	21,900			21,900			3.94	%		April 1, 2019
	Torrey Reserve—North Court (6)	21,075			21,377			7.22	%		June 1, 2019
	Torrey Reserve—VCI, VCII, VCIII (6)	7,101			7,200			6.36	%		June 1, 2020
	Solana Beach Corporate Centre I-II (6)	11,302			11,475			5.91	%		June 1, 2020
	Solana Beach Towne Centre (6)	37,675			38,249			5.91	%		June 1, 2020
	City Center Bellevue (1)	111,000			111,000			3.98	%		November 1, 2022
	Total	819,983			962,259
	Unamortized fair value adjustment	(7,172		)	(10,085		)
	Total Secured Notes Payable	$	812,811		$	952,174
	-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	Loan repaid in full, without premium or penalty, on February 6, 2015.
	-5	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.
	-6	Principal payments based on a 30-year amortization schedule.
	On October 10, 2012, the Operating Partnership entered into a ten-year non-recourse mortgage loan with PNC Bank, National Association with an original principal amount of $111.0 million. The loan is secured by a first-priority deed of trust on City Center Bellevue and an assignment of all leases, rents and security deposits relating to City Center Bellevue. The loan has a maturity date of November 1, 2022, bears interest at a fixed rate per annum of 3.98% and is interest only.
	On March 29, 2012, the Operating Partnership entered into a seven-year non-recourse mortgage loan with PNC Bank, National Association with an original principal amount of $21.9 million. The loan is secured by a first-priority deed of trust on One Beach Street and an assignment of all leases, rents and security deposits relating to One Beach Street. The loan has a maturity date of April 1, 2019, bears interest at a fixed rate per annum of 3.94% and is interest only.
	Unsecured notes payable
	The following is a summary of the Operating Partnership's total unsecured notes payable outstanding as of December 31, 2014 and December 31, 2013 (in thousands):
	Description of Debt	Principal Balance as of						Stated Interest Rate		Stated Maturity Date
		31-Dec-14			31-Dec-13			as of December 31, 2014
	Term Loan	$	100,000		$	—		Variable (1)		January 9, 2019 (2)
	Senior Guaranteed Notes, Series A	150,000			—			4.04% (3)		October 31, 2021
	Total Unsecured Notes Payable	$	250,000		$	—
	-1	The company has entered into an interest rate swap agreement that is intended to fix the interest rate associated with the loan term at approximately 3.08% through its maturity date and extension options, subject to adjustments based on the Operating Partnership's consolidated leverage ratio.
	-2	The Operating Partnership has an option to extend the term loan up to three times, with each such extension for a 12-month period. The foregoing extension options are exercisable by the Operating Partnership subject to the satisfaction of certain conditions.
	-3	The company entered into a one-month forward-starting seven-year swap contract on August 19, 2014, which was settled on September 19, 2014 at a gain of approximately $1.6 million (see Note 9). The forward-starting seven-year swap contract was deemed to be a highly effective cash flow hedge, accordingly, the effective interest rate is approximately 3.88% per annum.
	On October 31, 2014, the Operating Partnership entered into a note purchase agreement (the "Note Purchase Agreement") with a group of institutional purchasers that provided for the private placement of an aggregate of $350 million of senior guaranteed notes, of which (1) $150 million are designated as 4.04% Senior Guaranteed Notes, Series A, due October 31, 2021 (the “Series A Notes”), (2) $100 million are designated as 4.45% Senior Guaranteed Notes, Series B, due February 2, 2025 (the “Series B Notes”) and (3) $100 million are designated as 4.50% Senior Guaranteed Notes, Series C, due April 1, 2025 (the “Series C Notes”, and collectively with the Series A Notes and Series B Notes, are referred to herein as, the “Notes”). The Series A Notes were issued on October 31, 2014. The Series B Notes were issued on February 2, 2015 and the Series C Notes are expected to be issued on April 1, 2015, subject to customary closing conditions. Upon issuance, the Notes will pay interest quarterly on the last day of January, April, July and October until their respective maturities. As of December 31, 2014, $150 million of the Series A Notes were outstanding with an all in effective interest rate of approximately 3.88% (including interest rate swap costs).
	The Operating Partnership may prepay at any time all, or from time to time any part of, the Notes, in an amount not less than 5% of the aggregate principal amount of any series of the Notes then outstanding in the case of a partial prepayment, at 100% of the principal amount so prepaid plus a Make-Whole Amount (as defined in the Note Purchase Agreement).
	The Note Purchase Agreement contains a number of customary financial covenants, including, without limitation, tangible net worth thresholds, secured and unsecured leverage ratios and fixed charge coverage ratios. Subject to the terms of the Note Purchase Agreement and the Notes, upon certain events of default, including, but not limited to, (i) a default in the payment of any principal, Make-Whole Amount or interest under the Notes, and (ii) a default in the payment of certain other indebtedness by us or our subsidiaries, the principal, accrued and unpaid interest, and the Make-Whole Amount on the outstanding Notes will become due and payable at the option of the purchasers.
	The Operating Partnership's obligations under the Notes are fully and unconditionally guaranteed by the Operating Partnership and certain of the Operating Partnership's subsidiaries.
	Certain loans require the Operating Partnership to comply with various financial covenants, including the maintenance of minimum debt coverage ratios. As of December 31, 2014, the Operating Partnership was in compliance with all loan covenants.
	Scheduled principal payments on secured and unsecured notes payable as of December 31, 2014 are as follows (in thousands):
	2015	$	235,980
	2016	113,974
	2017	190,139
	2018	75,224
	2019	142,662
	Thereafter	312,004
		$	1,069,983
	Credit Facility
	On January 19, 2011, the company and the Operating Partnership entered into a revolving credit facility, or the credit facility. A group of lenders for which an affiliate of Merrill Lynch, Pierce, Fenner & Smith Incorporated acts as administrative agent and joint arranger, and an affiliate of Wells Fargo Securities, LLC acts as syndication agent and joint arranger, provided commitments for a revolving credit facility allowing borrowings of up to $250.0 million. The credit facility also had an accordion feature that allowed the Operating Partnership to increase the availability thereunder up to a maximum of $400.0 million, subject to meeting specified requirements and obtaining additional commitments from lenders. The credit facility bore interest at the rate of either LIBOR or a base rate, in each case plus a margin that varied depending on our leverage ratio. The amount available for us to borrow under the credit facility was subject to the net operating income of our properties that form the borrowing base of the facility and a minimum implied debt yield of such properties.
	On March 7, 2011, the credit facility was amended to allow the company or the Operating Partnership to purchase GNMA securities with maturities of up to 30 years. On January 10, 2012, the credit facility was amended a second time to (1) extend the maturity date to January 10, 2016 (with a one-year extension option), (2) decrease the applicable interest rates and (3) modify certain financial covenants contained therein. On September 7, 2012, the credit facility was amended a third time to allow our consolidated total secured indebtedness to be up to 55% of our secured total asset value for the period commencing upon the date that a material acquisition (generally, greater than $100 million) was consummated through and including the last day of the third fiscal quarter that followed such date.
	On January 9, 2014, the company and the Operating Partnership entered into an amended and restated credit agreement, or the amended and restated credit facility, which amended and restated the then in-place credit facility. The amended and restated credit facility provides for aggregate, unsecured borrowing of $350 million, consisting of a revolving line of credit of $250 million, or the revolver loan, and a term loan of $100 million, or the term loan. The amended and restated credit facility has an accordion feature that may allow the Operating Partnership to increase the availability thereunder up to an additional $250 million, subject to meeting specified requirements and obtaining additional commitments from lenders.
	On October 16, 2014, we entered into a first amendment to the amended and restated credit agreement that amends provisions of the amended and restated credit agreement to, among other things, (1) describe the treatment of our pari passu obligations under the amended and restated credit agreement and (2) remove the material acquisition provisions previously set forth in the amended and restated credit agreement.
Borrowings under the amended and restated credit facility initially bear interest at floating rates equal to, at our option, either (1) LIBOR, plus a spread which ranges from (a) 1.35%-1.95% (with respect to the revolver loan) and (b) 1.30% to 1.90% (with respect to the term loan), in each case based on our consolidated leverage ratio, or (2) a base rate equal to the highest of (a) the prime rate, (b) the federal funds rate plus 50 bps or (c) the Eurodollar rate plus 100 bps, plus a spread which ranges from (i) 0.35%-0.95% (with respect to the revolver loan) and (ii) 0.30% to 0.90% (with respect to the term loan), in each case based on our consolidated leverage ratio. The foregoing rates are more favorable than previously contained in the credit agreement in place as of December 31, 2013. If American Assets Trust, Inc. obtains an investment-grade debt rating, under the terms set forth in the amended and restated credit facility, the spreads will further improve.
The revolver loan initially matures on January 9, 2018, subject to the Operating Partnership's option to extend the revolver loan up to two times, with each such extension for a six-month period.
Concurrent with the closing of the amended and restated credit facility, the Operating Partnership drew down on the entirety of the $100 million term loan remains outstanding and is included in unsecured notes payable as discussed above.
Additionally, the amended and restated credit facility includes a number of financial covenants, including:
•	A maximum leverage ratio (defined as total indebtedness net of certain cash and cash equivalents to total asset value) of 60%,
•	A maximum secured leverage ratio (defined as total secured debt to secured total asset value) of 45% at any time prior to December 31, 2015, and 40% thereafter,
•	A minimum fixed charge coverage ratio (defined as consolidated earnings before interest, taxes, depreciation and amortization to consolidated fixed charges) of 1.50x,
•	A minimum unsecured interest coverage ratio of 1.75x,
•	A maximum unsecured leverage ratio of 60%,
•	A minimum tangible net worth of $721.16 million, and 75% of the net proceeds of any additional equity issuances (other than additional equity issuances in connection with any dividend reinvestment program), and
•	Recourse indebtedness at any time cannot exceed 15% of total asset value.
The amended and restated credit facility provides that American Assets Trust, Inc.'s annual distributions may not exceed the greater of (1) 95% of our funds from operations (“FFO”) or (2) the amount required for us to (a) qualify and maintain our REIT status and (b) avoid the payment of federal or state income or excise tax. If certain events of default exist or would result from a distribution, we may be precluded from making distributions other than those necessary to qualify and maintain our status as a REIT.
American Assets Trust, Inc. and certain of its subsidiaries guaranteed the obligations under the amended and restated credit facility, and certain of its subsidiaries pledged specified equity interests in our subsidiaries as collateral for our obligations under the amended and restated credit facility.
As of December 31, 2014, the Operating Partnership was in compliance with all then in-place amended and restated credit facility covenants.

Derivative_and_Hedging_Notes

Derivative and Hedging (Notes)	12 Months Ended
	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
DERIVATIVE AND HEDGING ACTIVITIES	DERIVATIVE AND HEDGING ACTIVITIES
	Our objectives in using interest rate derivatives are to add stability to interest expense and to manage exposure to interest rate movement.  To accomplish these objectives, we use interest rate swaps as part of our interest rate risk management strategy.  Interest rate swaps designated as cash flow hedges involve the receipt of variable-rate amounts from a counterparty in exchange for us making fixed-rate payments over the life of the agreements without exchange of the underlying notional amount.
	Concurrent with the closing of our amended and restated credit facility, we entered into an interest rate swap agreement that is intended to fix the interest rate associated with our term loan of $100 million at approximately 3.08% through its maturity date and extension options, subject to adjustments based on our consolidated leverage ratio. The following is a summary of the terms of the interest rate swap as of December 31, 2014 (dollars in thousands):
	Swap Counterparty	Notional Amount	Effective Date	Maturity Date	Fair Value
	Bank of America, N.A.	$100,000	1/9/14	1/9/19	$	1,448
	The effective portion of changes in the fair value of the derivatives that are designated as cash flow hedges are being recorded as accumulated other comprehensive income and will be subsequently reclassified into earnings during the period in which the hedged forecasted transaction affects earnings.
	The valuation of these instruments is determined using widely accepted valuation techniques including discounted cash flow analysis on the expected cash flows of the derivative.  This analysis reflects the contractual terms of the derivative, including the period to maturity, and uses observable market-based inputs, including interest rate curves, and implied volatilities.  The fair value of the interest rate swaps is determined using the market standard methodology of netting the discounted future fixed cash receipts (or payments) and the discounted expected variable cash payments (or receipts).  The variable cash payments (or receipts) are based on an expectation of future interest rates (forward curves) derived from observable market interest rate curves.
	Forward Starting Swap
	On August 19, 2014, we entered into a one-month forward-starting seven-year swap contract with Wells Fargo Bank, N.A. to reduce the interest rate variability exposure of the projected interest cash flows of our then-prospective Series A Notes. The forward-starting seven-year swap contract had a notional amount of $150 million, a termination date of October 31, 2014, a fixed pay rate of 2.1305%, a receive rate equal to the one-month LIBOR, with fixed rate payments due quarterly on the last day of each January, April, July and October commencing January 30, 2015, floating payments due quarterly on the last day of each January, April, July and October commencing January 30, 2015, and floating reset dates two days prior to the first day of each calculation period.  The forward-starting seven-year swap contract's accrual period, October 31, 2014 to October 31, 2021, was designed to match the expected tenor of the Series A Notes.
	The forward-starting seven-year swap contract was deemed to be a highly effective cash flow hedge and we elected to designate the forward-starting swap contract as an accounting hedge. We settled the forward-starting seven-year swap contract on September 19, 2014, resulting in a gain of approximately $1.6 million.  This gain is included in accumulated other comprehensive income and will be amortized to interest expense over the life of the Series A Notes.

Partners_Capital_of_American_A

Partners Capital of American Assets Trust, L.P. (Notes)	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
PARTNERS' CAPITAL OF AMERICAN ASSETS TRUST, L.P.	PARTNERS' CAPITAL OF AMERICAN ASSETS TRUST, L.P.
	As of December 31, 2014, the Operating Partnership had 17,905,257 common units (the “Noncontrolling Common Units”) outstanding. American Assets Trust, Inc. owned 70.7% of the Operating Partnership at December 31, 2014. The remaining 29.3% of the partnership interests are owned by non-affiliated investors and certain of our directors and executive officers. Common units and shares of the company's common stock have essentially the same economic characteristics in that common units and shares of the company's common stock share equally in the total net income or loss distributions of the Operating Partnership.
	American Assets Trust, Inc. is the Operating Partnership’s general partner and is responsible for the management of the Operating Partnership’s business. As the general partner of the Operating Partnership, the company effectively controls the ability to issue common stock of American Assets Trust, Inc. upon a limited partner’s notice of redemption. Investors who own common units have the right to cause the Operating Partnership to redeem any or all of their common units for cash equal to the then-current market value of one share of the company's common stock, or, at the company's election, shares of the company's common stock on a one-for-one basis. In addition, American Assets Trust, Inc. has generally acquired common units upon a limited partner’s notice of redemption in exchange for shares of the company's common stock. The redemption provisions of common units owned by limited partners that permit the Operating Partnership to settle in either cash or common stock at the option of the company are further evaluated in accordance with applicable accounting guidance to determine whether temporary or permanent equity classification on the balance sheet is appropriate. The Operating Partnership evaluated this guidance, including the requirement to settle in unregistered shares, and determined that these common units meet the requirements to qualify for presentation as permanent equity.
	During the years ended December 31, 2014, 2013 and 2012, approximately 11,852, 106,326 and 372,654, respectively, common units were converted into shares of the company's common stock.

Equity_of_American_Assets_Trus

Equity of American Assets Trust, Inc. (Notes)	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
EQUITY OF AMERICAN ASSETS TRUST, INC.	EQUITY OF AMERICAN ASSETS TRUST, INC.
	Stockholders' Equity
	On May 6, 2013, we entered into an at-the-market (“ATM”) equity program with four sales agents pursuant to which we may, from time to time, offer and sell shares of our common stock having an aggregate offering price of up to $150.0 million. The sales of shares of our common stock made through the ATM equity program are made in "at-the-market" offerings as defined in Rule 415 of the Securities Act of 1933, as amended ("the Securities Act"). For the year ended December 31, 2014, we issued 2,710,067 shares of common stock through the ATM equity program at a weighted average price per share of $33.84 for gross proceeds of $91.7 million and paid $0.9 million in sales agent compensation and $0.1 million in additional offering expenses related to the sales of these shares of common stock. As of December 31, 2014, we had the capacity to issue up to an additional $32.3 million in shares of our common stock under our ATM equity program. Actual future sales will depend on a variety of factors including, but not limited to, market conditions, the trading price of our common stock and our capital needs. We have no obligation to sell the remaining shares available for sale under the ATM equity program.
	On September 12, 2014, we entered into a common stock purchase agreement (the “Purchase Agreement”) with Insurance Company of the West, a California corporation ("ICW") which is an insurance company majority owned and controlled by Ernest Rady, the Executive Chairman of our board of directors ("Board of Directors"). The Purchase Agreement provided for the sale by the company to ICW, in a private placement, of 400,000 shares of the company's common stock at a purchase price of $33.76 per share, resulting in gross proceeds to the company of approximately $13.5 million. The price per share paid by ICW was equal to the closing price of a share of the company's common stock on the New York Stock Exchange on the date of the Purchase Agreement. These shares were registered in connection with the filing of our universal shelf registration statement on Form S-3 ASR on February 6, 2015.
	Preferred Stock Authorized Shares
	We have been authorized to issue 10,000,000 shares of preferred stock with a par value of $0.01, of which no shares were outstanding at December 31, 2014. Upon issuance, our Board of Directors has the ability to define the terms of the preferred shares, including voting rights, liquidation preferences, conversion and redemption provisions and dividend rates.
	Dividends
	The following table lists the dividends declared and paid on our shares of common stock and Noncontrolling Common Units for the years ended December 31, 2014, 2013 and 2012:
	Period		Amount per Share/Unit				Period Covered		Dividend Paid Date
	First Quarter 2012		$	0.21			January 1, 2012 to March 31, 2012		March 30, 2012
	Second Quarter 2012		$	0.21			April 1, 2012 to June 30, 2012		June 29, 2012
	Third Quarter 2012		$	0.21			July 1, 2012 to September 30, 2012		September 28, 2012
	Fourth Quarter 2012		$	0.21			October 1, 2012 to December 31, 2012		December 28, 2012
	First Quarter 2013		$	0.21			January 1, 2013 to March 31, 2013		March 29, 2013
	Second Quarter 2013		$	0.21			April 1, 2013 to June 30, 2013		June 28, 2013
	Third Quarter 2013		$	0.21			July 1, 2013 to September 30, 2013		September 27, 2013
	Fourth Quarter 2013		$	0.22			October 1, 2013 to December 31, 2013		December 27, 2013
	First Quarter 2014		$	0.22			January 1, 2014 to March 31, 2014		March 28, 2014
	Second Quarter 2014		$	0.22			April 1, 2014 to June 30, 2014		June 27, 2014
	Third Quarter 2014		$	0.22			July 1, 2014 to September 30, 2014		September 26, 2014
	Fourth Quarter 2014		$	0.2325			October 1, 2014 to December 31, 2014		December 26, 2014
	Taxability of Dividends
	Earnings and profits, which determine the taxability of distributions to stockholders and holders of common units, may differ from income reported for financial reporting purposes due to the differences for federal income tax purposes in the treatment of loss on extinguishment of debt, revenue recognition and compensation expense and in the basis of depreciable assets and estimated useful lives used to compute depreciation. A summary of the income tax status of dividends per share paid is as follows:
			Year Ended December 31,
			2014							2013					2012
			Per Share				%			Per Share			%		Per Share		%
	Ordinary income		$	0.61			68.9	%		$	0.83		97.6	%	$	0.56	66.7	%
	Return of capital		0.28				31.1	%		0.02			2.4	%	0.28		33.3	%
	Total		$	0.89			100	%		$	0.85		100	%	$	0.84	100	%
	Stock-Based Compensation
	The company has established the 2011 Equity Incentive Award Plan (the "2011 Plan"), which provides for grants to directors, employees and consultants of the company and the Operating Partnership of stock options, restricted stock, dividend equivalents, stock payments, performance shares, LTIP units, stock appreciation rights and other incentive awards. An aggregate of 4,054,411 shares of our common stock are authorized for issuance under awards granted pursuant to the 2011 Plan, and as of December 31, 2014, 3,560,872 shares of common stock remain available for future issuance.
	The following shares of restricted common stock have been issued as of December 31, 2014:
	Grant	Price at Grant Date	Number
	January 19, 2012 (1)	$11.91 - $12.61	2,000
	July 10, 2012 (2)	$25.05	8,015
	July 13, 2013 (2)	$31.97	5,004
	March 25, 2014 (3)	$28.89 - $31.25	112,119
	June 17, 2014 (4)	$34.10	5,864
	December 1, 2014 (5)	$36.28 - $36.32	98,765
	(1) Restricted common stock issued to certain of the company's senior management and other employees, which are subject to performance-based vesting. These shares vest in two substantially equal installments, with the first installment vested on the third anniversary of the date of grant and the second installment vesting on the fourth anniversary of the date of grant, subject to the employee's continued employment on those dates.
	(2) Restricted common stock issued to members of the company's non-employee directors. These awards of restricted stock vest ratably as to one-third of the shares granted on each of the first three anniversaries of the date of grant, subject to the director's continued service on our Board of Directors.
	(3) Restricted common stock issued to certain of the company's senior management and other employees, which are subject to pre-defined market specific performance criteria based vesting. Up to one-third of the shares of restricted stock may vest on each of November 30, 2014, 2015 and 2016, subject to the employee's continued employment on those dates.
	(4) Restricted common stock issued to members of the company's non-employee directors. These awards of restricted stock will vest subject to the director's continued service on the Board of Directors on the earlier of (i) the one year anniversary of the date of grant or (ii) the date of the next annual meeting of our stockholders, if such non-employee director continues his or her service on the Board of Directors until the next annual meeting of stockholders, but not thereafter, pursuant to our independent director compensation policy.
	(5) Restricted common stock issued to certain of the company's senior management and other employees, which are subject to pre-defined market specific performance criteria based vesting. Up to one-third of the shares of restricted stock may vest on each of November 30, 2015, 2016 and 2017, subject to the employee's continued employment on those dates.
	For the performance-based stock awards, the fair value of the awards was estimated using a Monte Carlo Simulation model. Our stock price, along with the stock prices of the group of peer REITs, is assumed to follow the Multivariate Geometric Brownian Motion Process. Multivariate Geometric Brownian Motion is a common assumption when modeling in financial markets, as it allows the modeled quantity (in this case, the stock price) to vary randomly from its current value and take any value greater than zero. The volatilities of the returns on the stock price of the company and the group REITs were estimated based on a three year look-back period. The expected growth rate of the stock prices over the “derived service period” of the employee is determined with consideration of the risk free rate as of the grant date. For the restricted stock grants that are time-vesting, we estimate the stock compensation expense based on the fair value of the stock at the grant date.
	The following table summarizes the activity of non-vested restricted stock awards during the year ended December 31, 2014:
		2014
		Units			Weighted Average Grant Date Fair Value
	Balance at beginning of year	629,058			$	15.58
	Granted	216,748			32.96
	Vested	(351,075	)		17.22
	Forfeited	(1,192	)		29.83
	Balance at end of year	493,539			$	22.01
	We recognize noncash compensation expense ratably over the vesting period, and accordingly, we recognized $3.7 million, $2.8 million and $2.9 million in noncash compensation expense for the years ended December 31, 2014, 2013 and 2012, each of which is included in general and administrative expense on the statement of income. Unrecognized compensation expense was $5.1 million at December 31, 2014, which will be recognized over a weighted-average period of 1.0 years.
	Earnings Per Share
	We have calculated earnings per share (“EPS”) under the two-class method. The two-class method is an earnings allocation methodology whereby EPS for each class of common stock and participating security is calculated according to dividends declared and participation rights in undistributed earnings. For the years ended December 31, 2014, 2013 and 2012, we had a weighted average of approximately 430,584 shares, 630,130 shares and 629,493 unvested shares outstanding, respectively, which are considered participating securities. Therefore, we have allocated our earnings for basic and diluted EPS between common shares and unvested shares.
	Diluted EPS is calculated by dividing the net income attributable to common stockholders for the period by the weighted average number of common and dilutive instruments outstanding during the period using the treasury stock method. For the year ended December 31, 2014, diluted shares exclude incentive restricted stock as these awards are considered contingently issuable. Additionally, the unvested restricted stock awards subject to time vesting are anti-dilutive for all periods presented and accordingly, have been excluded from the weighted average common shares used to compute diluted EPS.
	Earnings Per Unit of the Operating Partnership
	Basic earnings (loss) per unit (“EPU”) of the Operating Partnership is computed by dividing income (loss) applicable to unitholders by the weighted average Operating Partnership units outstanding, as adjusted for the effect of participating securities. Operating Partnership units granted in equity-based payment transactions are considered participating securities prior to vesting. The impact of unvested Operating Partnership unit awards on EPU has been calculated using the two-class method whereby earnings are allocated to the unvested Operating Partnership unit awards based on distributions and the unvested Operating Partnership units’ participation rights in undistributed earnings (losses).
	The calculation of diluted earnings per unit for the year ended December 31, 2014, 2013, and 2012 does not include 430,584 units, 630,130 units, and 629,493 unvested weighted average Operating Partnership units, respectively, as the effect of including these equity securities was anti-dilutive to income from continuing operations and net income attributable to the unitholders.
	The computation of basic and diluted EPS is presented below (dollars in thousands, except share and per share amounts):
		Year Ended December 31,
		2014				2013				2012
	NUMERATOR
Income from continuing operations	$	31,145			$	22,594			$	13,949
Less: Net income attributable to restricted shares	(374		)		(536		)		(529		)
Less: Income from continuing operations attributable to unitholders in the Operating Partnership	(9,015		)		(6,838		)		(4,239		)
Income from continuing operations attributable to American Assets Trust, Inc. common stockholders—basic	21,756				15,220				9,181
Plus: Results from discontinued operations attributable to American Assets Trust, Inc. common stockholders	—				—				25,757
Net income attributable to common stockholders—basic	$	21,756			$	15,220			$	34,938
Income from continuing operations attributable to American Assets Trust, Inc. common stockholders—basic	$	21,756			$	15,220			$	9,181
Plus: Income from continuing operations attributable to unitholders in the Operating Partnership	9,015				6,838				4,239
Income from continuing operations attributable to common stockholders—diluted	30,771				22,058				13,420
Plus: Results from discontinued operations attributable to American Assets Trust, Inc. common stockholders	—				—				25,757
Plus: Results from discontinued operations attributable to unitholders in the Operating Partnership	—				—				11,895
Net income attributable to common stockholders—diluted	$	30,771			$	22,058			$	51,072
DENOMINATOR
Weighted average common shares outstanding—basic	42,041,126				39,539,457				38,736,113
Effect of dilutive securities—conversion of Operating Partnership units	17,906,348				17,976,353				18,317,796
Weighted average common shares outstanding—diluted	59,947,474				57,515,810				57,053,909
Earnings per common share—basic
Continuing operations	$	0.52			$	0.38			$	0.24
Discontinued operations	—				—				0.66
	$	0.52			$	0.38			$	0.9
Earnings per common share—diluted
Continuing operations	$	0.51			$	0.38			$	0.24
Discontinued operations	—				—				0.66
	$	0.51			$	0.38			$	0.9

Income_Taxes_Notes

Income Taxes (Notes)	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES
	We elected to be taxed as a REIT and operate in a manner that allows us to qualify as a REIT, for federal income tax purposes commencing with our taxable year ending December 31, 2011. As a REIT, we are generally not subject to corporate level income tax on the earnings distributed currently to our stockholders that we derive from our REIT qualifying activities. Taxable income from non-REIT activities managed through our TRS is subject to federal and state income taxes.
	We lease our hotel property to a wholly owned TRS that is subject to federal and state income taxes. We account for income taxes using the asset and liability method, under which deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between GAAP carrying amounts and their respective tax bases. Additionally, we classify certain state taxes as income taxes for financial reporting purposes in accordance with ASC Topic 740, Income Taxes.
	A deferred tax liability is included in our consolidated balance sheets of $0.2 million as of December 31, 2014 and 2013, in relation to real estate asset basis differences and prepaid expenses for our TRS.
	The income tax provision included in other income (expense) on the consolidated statement of income is as follows (in thousands):
		Year Ended December 31, 2014			Year Ended December 31, 2013			Year Ended December 31, 2012
	Current:
	Federal	$	190		$	370		$	361
	State	284			362			335
	Deferred:
	Federal	$	—		$	(47	)	$	118
	State	(14		)	(40		)	202
	Provision for income taxes	$	460		$	645		$	1,016

Commitments_and_Contingencies_

Commitments and Contingencies (Notes)	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES
	Legal
	We are sometimes involved in various disputes, lawsuits, warranty claims, environmental and other matters arising in the ordinary course of business. Management makes assumptions and estimates concerning the likelihood and amount of any potential loss relating to these matters.
	We are currently a party to various legal proceedings. We accrue a liability for litigation if an unfavorable outcome is probable and the amount of loss can be reasonably estimated. If an unfavorable outcome is probable and a reasonable estimate of the loss is a range, we accrue the best estimate within the range; however, if no amount within the range is a better estimate than any other amount, the minimum within the range is accrued. Legal fees related to litigation are expensed as incurred. We do not believe that the ultimate outcome of these matters, either individually or in the aggregate, could have a material adverse effect on our financial position or overall trends in results of operations; however, litigation is subject to inherent uncertainties. Also, under our leases, tenants are typically obligated to indemnify us from and against all liabilities, costs and expenses imposed upon or asserted against us as owner of the properties due to certain matters relating to the operation of the properties by the tenant.
	Commitments
	At The Landmark at One Market, we lease, as lessee, a building adjacent to The Landmark under an operating lease effective through June 30, 2016, which we have the option to extend until 2031 by way of three five-year extension options.
	At Waikiki Beach Walk, we sublease a portion of the building of which Quiksilver is currently in possession, under an operating lease effective through December 31, 2021, which we have the option to extend at fair rental value in the event the sublessor extends its lease for the space with the master landlord. The lease payments under the lease will increase by approximately 3.4% annually through 2017 and, thereafter, will be equal to fair rental value, as defined in the lease, through lease expiration.
	Current minimum annual payments under the leases are as follows, as of December 31, 2014 (in thousands):
	2015	$	2,636
	2016	2,682		(1)
	2017	2,686		(2)
	2018	2,686
	2019	2,686
	Thereafter	23,856
	Total	$	37,232
	-1	Lease payments on The Landmark at One Market lease will be equal to fair rental value from July 2016 through the end of the options lease term. In the table, we have shown the option lease payments for this period based on the stated rate for the month of June 2016 of $162,140.
	-2	Lease payments on the Waikiki Beach Walk lease will be equal to fair rental value from March 2017 through the end of the lease term. In the table, we have shown the lease payments for this period based on the stated rate for the month of February 2017 of $61,690.
	We have management agreements with Outrigger Hotels & Resorts or an affiliate thereof (“Outrigger”) pursuant to which Outrigger manages each of the retail and hotel portions of the Waikiki Beach Walk property. Under the management agreement with Outrigger relating to the retail portion of Waikiki Beach Walk (the “retail management agreement”), we pay Outrigger a monthly management fee of 3.0% of net revenues from the retail portion of Waikiki Beach Walk. Pursuant to the terms of the retail management agreement, if the agreement is terminated in certain instances, including our election not to repair damage or destruction at the property, a condemnation or our failure to make required working capital infusions, we would be obligated to pay Outrigger a termination fee equal to the sum of the management fees paid for the two calendar months immediately preceding the termination date. The retail management agreement may not be terminated by us or by Outrigger without cause. Under our management agreement with Outrigger relating to the hotel portion of Waikiki Beach Walk (the “hotel management agreement”), we pay Outrigger a monthly management fee of 6.0% of the hotel's gross operating profit, as well as 3.0% of the hotel's gross revenues; provided that the aggregate management fee payable to Outrigger for any year shall not exceed 3.5% of the hotel's gross revenues for such fiscal year. Pursuant to the terms of the hotel management agreement, if the agreement is terminated in certain instances, including upon a transfer by us of the hotel or upon a default by us under the hotel management agreement, we would be required to pay a cancellation fee calculated by multiplying (1) the management fees for the previous 12 months by (2) (a) eight, if the agreement is terminated in the first 11 years of its term, or (b) four, three, two or one, if the agreement is terminated in the twelfth, thirteenth, fourteenth or fifteenth year, respectively, of its term. The hotel management agreement may not be terminated by us or by Outrigger without cause.
	A wholly owned subsidiary of our Operating Partnership, WBW Hotel Lessee LLC, entered into a franchise license agreement with Embassy Suites Franchise LLC, the franchisor of the brand “Embassy Suites™,” to obtain the non-exclusive right to operate the hotel under the Embassy Suites brand for 20 years. The franchise license agreement provides that WBW Hotel Lessee LLC must comply with certain management, operational, record keeping, accounting, reporting and marketing standards and procedures. In connection with this agreement, we are also subject to the terms of a product improvement plan pursuant to which we expect to undertake certain actions to ensure that our hotel's infrastructure is maintained in compliance with the franchisor's brand standards. In addition, we must pay to Embassy Suites Franchise LLC a monthly franchise royalty fee equal to 4.0% of the hotel's gross room revenue through December 2021 and 5.0% of the hotel's gross room revenue thereafter, as well as a monthly program fee equal to 4.0% of the hotel's gross room revenue. If the franchise license is terminated due to our failure to make required improvements or to otherwise comply with its terms, we may be liable to the franchisor for a termination payment, which could be as high as $6.6 million based on operating performance through December 31, 2014.
	Our Del Monte Center property has ongoing environmental remediation related to ground water contamination. The environmental issue existed at purchase and is currently in the final stages of remediation. The final stages of the remediation will include routine, long term ground monitoring by the appropriate regulatory agency over the next two to nine years. The work performed is financed through an escrow account funded by the seller upon our purchase of the Del Monte Center. We believe the funds in the escrow account are sufficient for the remaining work to be performed. However, if further work is required costing more than the remaining escrow funds, we could be required to pay such overage, although we may have a contractual claim for such costs against the prior owner or our environmental remediation consultant.
	In connection with the Offering, we entered into tax protection agreements with certain limited partners of our Operating Partnership. These agreements provide that if we dispose of any interest with respect to Carmel Country Plaza, Carmel Mountain Plaza, Del Monte Center, Loma Palisades, Lomas Santa Fe Plaza, Waikele Center or the ICW Plaza portion of Torrey Reserve Campus, in a taxable transaction during the period from the closing of the Offering through January 19, 2018, we will indemnify such limited partners for their tax liabilities attributable to their share of the built-in gain that existed with respect to such property interest as of the time of the Offering and tax liabilities incurred as a result of the reimbursement payment. Subject to certain exceptions and limitations, the indemnification rights will terminate for any such protected partner that sells, exchanges or otherwise disposes of more than 50% of his or her common units. We have no present intention to sell or otherwise dispose of the properties or interest therein in taxable transactions during the restriction period. If we were to trigger the tax protection provisions under these agreements, we would be required to pay damages in the amount of the taxes owed by these limited partners (plus additional damages in the amount of the taxes incurred as a result of such payment).
	As of December 31, 2014, the company accrued approximately $6.6 million for transfer taxes in connection with its Offering. The company believes that it has filed all necessary forms with the requisite taxing authorities.
	Concentrations of Credit Risk
	Our properties are located in Southern California, Northern California, Hawaii, Oregon, Texas and Washington. The ability of the tenants to honor the terms of their respective leases is dependent upon the economic, regulatory and social factors affecting the markets in which the tenants operate. Twelve of our consolidated properties, representing 29.9% of our total revenue for the year ended December 31, 2014, are located in Southern California, which exposes us to greater economic risks than if we owned a more geographically diverse portfolio. Our mixed-use property located in Honolulu, Hawaii accounted for 20.9% of total revenues for the year ended December 31, 2014.
	Tenants in the retail industry accounted for 37.0% and 36.6% of total revenues for the years December 31, 2014 and 2013, respectively. This makes us susceptible to demand for retail rental space and subject to the risks associated with an investment in real estate with a concentration of tenants in the retail industry. Two retail properties, Alamo Quarry Market and Waikele Center, accounted for 15.6% and 15.8% of total revenues for the years ended December 31, 2014 and 2013, respectively.
	Tenants in the office industry accounted for 35.6% and 35.5% of total revenues for the years December 31, 2014 and 2013, respectively. This makes us susceptible to demand for office rental space and subject to the risks associated with an investment in real estate with a concentration of tenants in the office industry.
	For the years ended December 31, 2014 and 2013, no tenant accounted for more than 10.0% of our total rental revenue. At December 31, 2014, salesforce.com, inc. at The Landmark at One Market accounted for 8.0% of total annualized base rent. Three other tenants (Autodesk, Inc., Lowe's, and Kmart) comprise 8.7% of our total annualized base rent at December 31, 2014, in the aggregate. No other tenants represent greater than 2.0% of our total annualized base rent. Total annualized base rent used for the percentage calculations includes the annualized base rent as of December 31, 2014 for our office properties, retail properties and the retail portion of our mixed-use property.

Operating_Leases_Notes

Operating Leases (Notes)	12 Months Ended
	Dec. 31, 2014
Leases, Operating [Abstract]
OPERATING LEASES	OPERATING LEASES
	At December 31, 2014, our retail, office and mixed-use properties are located in five states: California, Oregon, Hawaii, Washington and Texas. At December 31, 2014, we had approximately 829 leases with office and retail tenants, including the retail portion of our mixed-use property. Our multifamily properties are located in Southern California, and we had approximately 794 leases with residential tenants at December 31, 2014, excluding Santa Fe Park RV Resort.
	Our leases with office, retail, mixed-use and residential tenants are classified as operating leases. Leases at our office and retail properties and the retail portion of our mixed-use property generally range from three to ten years (certain leases with anchor tenants may be longer), and in addition to minimum rents, usually provide for cost recoveries for the tenant's share of certain operating costs and also may include percentage rents based on the tenant's level of sales achieved. Leases on apartments generally range from seven to fifteen months, with a majority having 12 month lease terms. Rooms at the hotel portion of our mixed-use property are rented on a nightly basis.
	As of December 31, 2014, minimum future rentals from noncancelable operating leases before any reserve for uncollectible amounts and assuming no early lease terminations, at our office and retail properties and the retail portion of our mixed-use property are as follows for the years ended December 31 (in thousands):
	2015	$	159,988
	2016	144,660
	2017	128,865
	2018	96,844
	2019	69,309
	Thereafter	193,704
	Total	$	793,370
	The above future minimum rentals exclude residential leases, which are typically range from seven to 15 months, and exclude the hotel, as rooms are rented on a nightly basis.

Component_of_Rental_Income_and

Component of Rental Income and Expense (Notes)	12 Months Ended
	Dec. 31, 2014
Operating Leases, Income Statement, Lease Revenue [Abstract]
COMPONENTS OF RENTAL INCOME AND EXPENSE	COMPONENTS OF RENTAL INCOME AND EXPENSE
	The principal components of rental income are as follows (in thousands):
		Year Ended December 31,
		2014		2013		2012
	Minimum rents
	Retail	$	70,573	$	69,374	$	67,046
	Office	82,018		81,845		71,817
	Multifamily	15,732		14,926		13,796
	Mixed-Use	10,004		9,549		8,893
	Cost reimbursement	29,052		27,583		27,763
	Percentage rent	3,107		2,655		2,608
	Hotel revenue	33,911		35,137		31,729
	Other	1,681		1,688		1,597
	Total rental income	$	246,078	$	242,757	$	225,249
	Minimum rents include $1.9 million, $2.6 million and $7.2 million for the years ended December 31, 2014, 2013 and 2012, respectively, to recognize minimum rents on a straight-line basis. In addition, minimum rents include $2.8 million, $2.4 million and $(0.2) million for the years ended December 31, 2014, 2013 and 2012, respectively, to recognize the amortization of above and below market leases.
	The principal components of rental expenses are as follows (in thousands):
		Year Ended December 31,
		2014		2013		2012
	Rental operating	$	26,371	$	26,028	$	24,264
	Hotel operating	21,488		22,115		20,905
	Repairs and maintenance	10,600		10,514		9,452
	Marketing	1,623		1,547		1,266
	Rent	2,452		2,442		2,378
	Hawaii excise tax	3,981		4,153		3,813
	Management fees	1,752		1,809		2,011
	Total rental expenses	$	68,267	$	68,608	$	64,089

Other_Income_Expenses_Notes

Other Income (Expenses) (Notes)	12 Months Ended
	Dec. 31, 2014
Other Income and Expenses [Abstract]
OTHER INCOME (EXPENSE)	OTHER INCOME (EXPENSE)
	The principal components of other income (expense), net are as follows (in thousands):
		Year Ended December 31,
		2014			2013			2012
	Interest and investment income	$	155		$	148		$	336
	Income tax expense	(460		)	(645		)	(1,016		)
	Acquisition related expenses	—			—			(152		)
	Other non-operating income	746			10			203
	Total other income (expense)	$	441		$	(487	)	$	(629	)

Related_Party_Transactions_Not

Related Party Transactions (Notes)	12 Months Ended
	Dec. 31, 2014
Related Party Transactions [Abstract]
RELATED PARTY TRANSACTIONS	RELATED PARTY TRANSACTIONS
	At Torrey Reserve Campus, we lease space to ICW. Rental revenue recognized on the leases of $2.2 million, $2.2 million and $2.1 million for the years ended December 31, 2014, 2013 and 2012, respectively, is included in rental income. Additionally, on July 1, 2014, we entered into a workers' compensation insurance policy with ICW. The policy premium is approximately $0.4 million for the period July 1, 2014 through July 1, 2015.
	On September 12, 2014, the company entered into a common stock purchase agreement (the “Purchase Agreement”) with ICW. The Purchase Agreement provides for the sale by the company to ICW, in a private placement, of 400,000 shares of common stock at a price of $33.76 per share, resulting in gross proceeds to the company of approximately $13.5 million. See Note 11.
	The Waikiki Beach Walk entities have a 47.7% investment in WBW CHP LLC, an entity that was formed to, among other things, construct a chilled water plant to provide air conditioning to the property and other adjacent facilities. The operating expenses of WBW CHP LLC are recovered through reimbursements from its members, and reimbursements to WBW CHP LLC of $1.1 million, $1.1 million and $1.0 million were made for the years ended December 31, 2014, 2013 and 2012 and included in rental expenses on the statements of income.

Segment_Reporting_Notes

Segment Reporting (Notes)	12 Months Ended
	Dec. 31, 2014
Segment Reporting [Abstract]
SEGMENT REPORTING	SEGMENT REPORTING
	Segment information is prepared on the same basis that our management reviews information for operational decision-making purposes. We review operating and financial information for each property on an individual basis and therefore, each property represents an individual operating segment. However, we have aggregated our properties into reportable segments as the properties share similar long-term economic characteristics and have other similarities including the fact that they are operated using consistent business strategies.
	We operate in four business segments: the acquisition, redevelopment, ownership and management of retail real estate, office real estate, multifamily real estate and mixed-use real estate. The products for our retail segment primarily include rental of retail space and other tenant services, including tenant reimbursements, parking and storage space rental. The products for our office segment primarily include rental of office space and other tenant services, including tenant reimbursements, parking and storage space rental. The products for our multifamily segment include rental of apartments and other tenant services. The products of our mixed-use segment include rental of retail space and other tenant services, including tenant reimbursements, parking and storage space rental and operation of a 369-room all-suite hotel.
	We evaluate the performance of our segments based on segment profit which is defined as property revenue less property expenses. We do not use asset information as a measure to assess performance and make decisions to allocate resources. Therefore, depreciation and amortization expense is not allocated among segments. General and administrative expenses, interest expense, depreciation and amortization expense and other income and expense are not included in segment profit as our internal reporting addresses these items on a corporate level.
	Segment profit is not a measure of operating income or cash flows from operating activities as measured by GAAP, and it is not indicative of cash available to fund cash needs and should not be considered an alternative to cash flows as a measure of liquidity. Not all companies calculate segment profit in the same manner. We consider segment profit to be an appropriate supplemental measure to net income because it assists both investors and management in understanding the core operations of our properties.
	The following table represents operating activity within our reportable segments (in thousands):
		Year Ended December 31,
		2014			2013			2012
	Total Retail
	Property revenue	$	96,140		$	93,449		$	91,991
	Property expense	(25,451		)	(23,900		)	(24,955		)
	Segment profit	70,689			69,549			67,036
	Total Office
	Property revenue	92,474			90,527			78,101
	Property expense	(27,003		)	(26,688		)	(23,780		)
	Segment profit	65,471			63,839			54,321
	Total Multifamily
	Property revenue	16,976			16,125			14,852
	Property expense	(6,099		)	(5,917		)	(5,914		)
	Segment profit	10,877			10,208			8,938
	Total Mixed-Use
	Property revenue	54,410			54,956			50,522
	Property expense	(32,678		)	(33,481		)	(31,465		)
	Segment profit	21,732			21,475			19,057
	Total segments’ profit	$	168,769		$	165,071		$	149,352
	The following table is a reconciliation of segment profit to net income attributable to stockholders (in thousands):
		Year Ended December 31,
		2014			2013			2012
	Total segments' profit	$	168,769		$	165,071		$	149,352
	General and administrative	(18,532		)	(17,195		)	(15,593		)
	Depreciation and amortization	(66,568		)	(66,775		)	(61,853		)
	Interest expense	(52,965		)	(58,020		)	(57,328		)
	Other income (expense), net	441			(487		)	(629		)
	Income from continuing operations	31,145			22,594			13,949
	Discontinued operations
	Income from discontinued operations	—			—			932
	Gain on sale of real estate property	—			—			36,720
	Results from discontinued operations	—			—			37,652
	Net income	31,145			22,594			51,601
	Net income attributable to restricted shares	(374		)	(536		)	(529		)
	Net income attributable to unitholders in the Operating Partnership	(9,015		)	(6,838		)	(16,134		)
	Net income attributable to American Assets Trust, Inc. stockholders	$	21,756		$	15,220		$	34,938
	The following table shows net real estate and secured note payable balances for each of the segments, along with their capital expenditures for each year (in thousands):
		December 31, 2014			December 31, 2013
	Net real estate
	Retail	$	639,456		$	651,707
	Office	757,854			750,890
	Multifamily	182,468			74,612
	Mixed-Use	195,622			199,627
		$	1,775,400		$	1,676,836
	Secured Notes Payable (1)
	Retail	$	161,975		$	303,249
	Office	426,254			427,256
	Multifamily	101,444			101,444
	Mixed-Use	130,310			130,310
		$	819,983		$	962,259
	Capital Expenditures (2)
	Retail	$	8,671		$	4,849
	Office	34,577			27,275
	Multifamily	101,392			24,641
	Mixed-Use	5,132			1,942
		$	149,772		$	58,707
	-1	Excludes unamortized fair market value adjustment of $7.2 million and $10.1 million as of December 31, 2014 and 2013, respectively.
	-2	Capital expenditures represent cash paid for capital expenditures during the year and include leasing commissions paid.

Quarterly_Financial_Informatio

Quarterly Financial Information (Unaudited) (Notes)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
QUARTERLY FINANCIAL INFORMATION (UNAUDITED)	QUARTERLY FINANCIAL INFORMATION (UNAUDITED)
	The tables below reflect selected American Assets Trust, Inc. quarterly information for 2014 and 2013 (in thousands, except per shares data):
		Three Months Ended
		December 31,			September 30,			June 30,			March 31,
		2014			2014			2014			2014
	Total revenue	$	66,478		$	67,343		$	62,199		$	63,980
	Operating income	22,526			23,036			17,726			20,381
	Net income	10,046			9,090			5,351			6,658
	Net income attributable to restricted shares	(115		)	(95		)	(94		)	(70		)
	Net income attributable to unitholders in the Operating Partnership	(2,907		)	(2,578		)	(1,544		)	(1,986		)
	Net income attributable to American Assets Trust, Inc. stockholders	$	7,024		$	6,417		$	3,713		$	4,602
	Net income from continuing operations attributable to common stockholders - basic and diluted	$	0.16		$	0.15		$	0.09		$	0.11
	Net income attributable to common stockholders - basic and diluted	$	0.16		$	0.15		$	0.09		$	0.11
		Three Months Ended
		December 31,			September 30,			June 30,			March 31,
		2013			2013			2013			2013
	Total revenue	$	64,645		$	65,318		$	62,914		$	62,180
	Operating income	20,407			21,441			19,373			19,880
	Net income	6,907			6,258			4,564			4,865
	Net income attributable to restricted shares	(139		)	(132		)	(133		)	(132		)
	Net income attributable to unitholders in the Operating Partnership	(2,086		)	(1,903		)	(1,354		)	(1,495		)
	Net income attributable to American Assets Trust, Inc. stockholders	$	4,682		$	4,223		$	3,077		$	3,238
	Net income from continuing operations attributable to common stockholders- basic and diluted	$	0.11		$	0.11		$	0.08		$	0.08
	Net income attributable to common stockholders - basic and diluted	$	0.11		$	0.11		$	0.08		$	0.08
	The tables below reflect selected American Assets Trust, L.P. quarterly information for 2014 and 2013 (in thousands, except per shares data):
		Three Months Ended
		December 31,			September 30,			June 30,			March 31,
		2014			2014			2014			2014
	Total revenue	$	66,478		$	67,343		$	62,199		$	63,980
	Operating income	22,526			23,036			17,726			20,381
	Net income	10,046			9,090			5,351			6,658
	Net income attributable to restricted shares	(115		)	(95		)	(94		)	(70		)
	Net income attributable to unitholders in the Operating Partnership	(2,907		)	(2,578		)	(1,544		)	(1,986		)
	Net income attributable to American Assets Trust, L.P. stockholders	$	7,024		$	6,417		$	3,713		$	4,602
	Net income from continuing operations attributable to common stockholders - basic and diluted	$	0.16		$	0.15		$	0.09		$	0.11
	Net income attributable to common stockholders - basic and diluted	$	0.16		$	0.15		$	0.09		$	0.11
		Three Months Ended
		December 31,			September 30,			June 30,			March 31,
		2013			2013			2013			2013
	Total revenue	$	64,645		$	65,318		$	62,914		$	62,180
	Operating income	20,407			21,441			19,373			19,880
	Net income	6,907			6,258			4,564			4,865
	Net income attributable to restricted shares	(139		)	(132		)	(133		)	(132		)
	Net income attributable to unitholders in the Operating Partnership	(2,086		)	(1,903		)	(1,354		)	(1,495		)
	Net income attributable to American Assets Trust, L.P. stockholders	$	4,682		$	4,223		$	3,077		$	3,238
	Net income from continuing operations attributable to common stockholders- basic and diluted	$	0.11		$	0.11		$	0.08		$	0.08
	Net income attributable to common stockholders - basic and diluted	$	0.11		$	0.11		$	0.08		$	0.08

Subsequent_Events_Notes

Subsequent Events (Notes)	12 Months Ended
	Dec. 31, 2014
Subsequent Events [Abstract]
SUBSEQUENT EVENT	SUBSEQUENT EVENTS
	On February 2, 2015, we closed on and issued our Series B Notes. As of February 20, 2015, $100 million of the Series B Notes was outstanding.
	Additionally, on February 2, 2015 and February 6, 2015, we prepaid in full, without penalty or premium, the secured mortgages encumbering The Shops at Kalakaua and Del Monte Center, respectively.

SCHEDULE_IIIConsolidated_Real_

SCHEDULE III-Consolidated Real Estate and Accumulated Depreciation (Notes)	12 Months Ended
	Dec. 31, 2014
SEC Schedule III, Real Estate and Accumulated Depreciation Disclosure [Abstract]
SCHEDULE III-Consolidated Real Estate and Accumulated Depreciation
		Encumbrance as of December 31, 2014			Initial Cost						Cost Capitalized Subsequent to Acquisition		Gross Carrying Amount				Accumulated			Year Built/	Date Acquired	Life on which depreciation in latest income statements is computed
													at December 31, 2014				Depreciation and			Renovated
	Description				Land			Building and					Land		Building and		Amortization
								Improvements							Improvements
	Alamo Quarry Market	$	—		$	26,396		$	109,294		$	13,181	$	26,816	$	122,055	$	(41,786	)	1997/1999	12/9/03	35 years
	Carmel Country Plaza	—			4,200			—			11,639		4,200		11,639		(6,871		)	1991	1/10/89	35 years
	Carmel Mountain Plaza	—			22,477			65,217			23,719		31,035		80,378		(28,807		)	1994/2014	3/28/03	35 years
	Del Monte Center	82,300			27,412			87,570			22,300		27,117		110,165		(45,368		)	1967/1984/2006	4/8/04	35 years
	Geary Marketplace	—			8,239			12,353			129		8,238		12,483		(818		)	2012	12/19/12	35 years
	Lomas Santa Fe Plaza	—			8,600			11,282			11,269		8,620		22,531		(13,225		)	1972/1997	6/12/95	35 years
	Rancho Carmel Plaza	—			3,450			—			3,914		3,487		3,877		(2,243		)	1993	4/30/90	35 years
	The Shops at Kalakaua	19,000			13,993			10,919			100		14,006		11,006		(3,364		)	1971/2006	3/31/05	35 years
	Solana Beach Towne Centre	37,675			40,980			38,842			1,854		40,980		40,696		(5,419		)	1973/2000/2004	1/19/11	35 years
	South Bay Marketplace	23,000			4,401			—			10,751		4,401		10,751		(6,112		)	1997	9/16/95	35 years
	Waikele Center	—			55,593			126,858			59,021		70,643		170,829		(51,137		)	1993/2008	9/16/04	35 years
	City Center Bellevue	111,000			25,135			190,998			10,674		25,135		201,672		(15,254		)	1987	8/21/12	40 years
	First & Main	84,500			14,697			109,739			3,095		14,697		112,834		(13,796		)	2010	3/11/11	40 years
	The Landmark at One Market	133,000			34,575			141,196			7,994		34,575		149,190		(20,780		)	1917/2000	6/30/10	40 years
	Lloyd District Portfolio	—			18,660			61,401			151,933		18,875		213,119		(9,597		)	1940-2011/present	7/1/11	40 years
	One Beach Street	21,900			15,332			18,017			2,367		15,332		20,384		(1,971		)	1924/1972/1987/1992	1/24/12	40 years
	Solana Beach Corporate Centre:
	Solana Beach Corporate Centre I-II	11,302			7,111			17,100			2,795		7,111		19,895		(2,480		)	1982/2005	1/19/11	40 years
	Solana Beach Corporate Centre III-IV	36,376			7,298			27,887			1,231		7,298		29,118		(4,003		)	1982/2005	1/19/11	40 years
	Solana Beach Corporate Centre Land	—			487			—			60		547		—		—			N/A	1/19/11	N/A
	Torrey Reserve:
	ICW Plaza	—			4,095			—			39,064		5,408		37,751		(10,918		)	1996-1997/2014	6/6/89	40 years
	Pacific North Court	21,075			3,263			—			20,885		4,309		19,839		(9,160		)	1997-1998	6/6/89	40 years
	Pacific South Court	—			3,285			—			22,021		4,226		21,080		(10,003		)	1996-1997	6/6/89	40 years
	Pacific VC	7,101			1,413			—			8,180		2,148		7,445		(4,099		)	1998/2000	6/6/89	40 years
	Pacific Torrey Daycare	—			715			—			1,671		911		1,475		(769		)	1996-1997	6/6/89	40 years
	Torrey Reserve Building 6	—			—			—			7,907		682		7,225		(297		)	2013	6/6/89	40 years
	Torrey Reserve Land	—			229			—			19,912		3,205		16,936		—			2014-present	6/6/89	N/A
	Imperial Beach Gardens	20,000			1,281			4,820			4,180		1,281		9,000		(7,512		)	1959/2008-present	7/31/85	30 years
	Loma Palisades	73,744			14,000			16,570			18,304		14,051		34,823		(24,049		)	1958/2001-2008	7/20/90	30 years
	Mariner’s Point	7,700			2,744			4,540			1,187		2,744		5,727		(2,479		)	1986	5/9/01	30 years
	Santa Fe Park RV Resort	—			401			928			818		401		1,746		(1,391		)	1971/2007-2008	6/1/79	30 years
	Waikiki Beach Walk:
	Retail	130,310			45,995			74,943			42		45,995		74,985		(9,315		)	2006	1/19/11	35 years
	Hotel	—			30,640			60,029			535		30,640		60,564		(7,248		)	2008/2014	1/19/11	35 years
	Solana Beach - Highway 101 Land	—			7,847			202			795		8,844		—		(189		)	N/A	9/20/11	N/A
	Sorrento Valley Holdings Land	—			2,073			741			4,834		6,145		1,503		(964		)	N/A	5/9/97	N/A
		$	819,983		$	457,017		$	1,191,446		$	488,361	$	494,103	$	1,642,721	$	(361,424	)
	(1) For Federal tax purposes, the aggregate tax basis is approximately $1.4 billion as of December 31, 2014.
		Year Ended December 31,
		2014			2013			2012
	Real estate assets
	Balance, beginning of period	$	1,995,417		1,938,676			1,687,276
	Additions:
	Property acquisitions	—			—			270,082
	Improvements (1)	154,594			60,677			41,303
	Deductions:
	Cost of Real Estate Sold	—			—			(57,188		)
	Other (1)(2)	(13,187		)	(3,936		)	(2,797		)
	Balance, end of period	$	2,136,824		$	1,995,417		$	1,938,676
	Accumulated depreciation
	Balance, beginning of period	$	318,581		$	270,494		$	234,595
	Additions—depreciation (1)	55,159			51,949			47,792
	Deductions:
	Cost of Real Estate Sold	—			—			(9,216		)
	Other (1)(2)	(12,316		)	(3,862		)	(2,677		)
	Balance, end of period	$	361,424		$	318,581		$	270,494
	-1	Includes discontinued operations for 160 King Street, which was sold on December 4, 2012.
	-2	Other deductions for the years ended December 31, 2014, 2013 and 2012 represent the write-off of fully depreciated assets.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Business and Organization	Business and Organization
	American Assets Trust, Inc. (which may be referred to in these financial statements as the “company,” “we,” “us,” or “our”) is a Maryland corporation formed on July 16, 2010 that did not have any operating activity until the consummation of our initial public offering (the “Offering”) and the related acquisition on January 19, 2011 of certain assets of a combination of entities whose assets included entities owned and/or controlled by Ernest S. Rady and his affiliates, including the Rady Trust, which in turn owned (1) controlling interests in entities owning 17 properties and the property management business of American Assets, Inc. and (2) noncontrolling interests in entities owning four properties. The company is the sole general partner of American Assets Trust, L.P., a Maryland limited partnership formed on July 16, 2010 (the “Operating Partnership”). The company's operations are carried on through our Operating Partnership and its subsidiaries, including our taxable REIT subsidiary. Since the formation of our Operating Partnership, the company has controlled our Operating Partnership as its general partner and has consolidated its assets, liabilities and results of operations.
	We are a vertically integrated and self-administered REIT with 113 employees providing substantial in-house expertise in asset management, property management, property development, leasing, tenant improvement construction, acquisitions, repositioning, redevelopment and financing.
	Any reference to the number of properties or units and square footage or acres are unaudited and outside the scope of our independent registered public accounting firm's audit of our financial statements in accordance with the standards of the United States Public Company Accounting Oversight Board.
	As of December 31, 2014, we owned or had a controlling interest in 23 office, retail, multifamily and mixed-use operating properties, the operations of which we consolidate. Additionally, as of December 31, 2014, we owned land at five of our properties that we classify as held for development and construction in progress. A summary of the properties owned by us is as follows:
	Retail
	Carmel Country Plaza	Del Monte Center
	Carmel Mountain Plaza	Geary Marketplace
	South Bay Marketplace	The Shops at Kalakaua
	Rancho Carmel Plaza	Waikele Center
	Lomas Santa Fe Plaza	Alamo Quarry Market
	Solana Beach Towne Centre
	Office
	Torrey Reserve Campus	Lloyd District Portfolio
	Solana Beach Corporate Centre	City Center Bellevue
	The Landmark at One Market
	One Beach Street
	First & Main
	Multifamily
	Loma Palisades
	Imperial Beach Gardens
	Mariner's Point
	Santa Fe Park RV Resort
	Mixed-Use
	Waikiki Beach Walk Retail and Embassy Suites™ Hotel
	Held for Development and Construction in Progress
	Solana Beach Corporate Centre – Land
	Solana Beach – Highway 101 – Land
	Sorrento Pointe – Land
	Torrey Reserve – Construction in Progress
	Lloyd District Portfolio – Construction in Progress
Basis of Presentation	Basis of Presentation
	Our consolidated financial statements include the accounts of the company, our Operating Partnership and our subsidiaries. The equity interests of other investors in our Operating Partnership are reflected as noncontrolling interests.
	All significant intercompany transactions and balances are eliminated in consolidation.
Use of Estimates	Use of Estimates
	The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America, referred to as “GAAP,” requires management to make estimates and assumptions that in certain circumstances affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities, and revenues and expenses. These estimates are prepared using management's best judgment, after considering past, current and expected events and economic conditions. Actual results could differ from these estimates.
Consolidated Statements of Cash Flows-Supplemental Disclosures	Consolidated Statements of Cash Flows-Supplemental Disclosures
	The following table provides supplemental disclosures related to the Consolidated Statements of Cash Flows (in thousands):
		Year Ended December 31,
		2014		2013		2012
	Supplemental cash flow information
	Total interest costs incurred	$	58,455	$	60,133	$	58,074
	Interest capitalized	$	5,490	$	2,113	$	746
	Interest expense	$	52,965	$	58,020	$	57,328
	Cash paid for interest, net of amounts capitalized (including discontinued operations)	$	48,032	$	54,345	$	55,349
	Cash paid for income taxes	$	404	$	901	$	1,239
	Supplemental schedule of noncash investing and financing activities
	Accounts payable and accrued liabilities for construction in progress	$	9,908	$	5,001	$	4,944
	Accrued leasing commissions	$	763	$	1,385	$	(782	)
	Accrued placement fees for senior guaranteed notes payable	$	750	$	—	$	—
	Reduction to capital for prepaid equity financing costs	$	40	$	437	$	—
Revenue Recognition and Accounts Receivable	Revenue Recognition and Accounts Receivable
	Our leases with tenants are classified as operating leases. Substantially all such leases contain fixed rent escalations which occur at specified times during the term of the lease. Base rents are recognized on a straight-line basis from when the tenant controls the space through the term of the related lease, net of valuation adjustments, based on management's assessment of credit, collection and other business risks. When we determine that we are the owner of tenant improvements and the tenant has reimbursed us for a portion or all of the tenant improvement costs, we consider the amount paid to be additional rent, which is recognized on a straight-line basis over the term of the related lease. For first generation tenants, in instances in which we fund tenant improvements and the improvements are deemed to be owned by us, revenue recognition will commence when the improvements are substantially completed and possession or control of the space is turned over to the tenant. When we determine that the tenant is the owner of tenant improvements, tenant allowances are recorded as lease incentives and we commence revenue recognition and lease incentive amortization when possession or control of the space is turned over to the tenant for tenant work to begin. Percentage rents, which represent additional rents based upon the level of sales achieved by certain tenants, are recognized at the end of the lease year or earlier if we have determined the required sales level is achieved and the percentage rents are collectible. Real estate tax and other cost reimbursements are recognized on an accrual basis over the periods in which the related expenditures are incurred.
	Other property income includes parking income, general excise tax billed to tenants and fees charged to tenants at our multifamily properties. Other property income is recognized when earned. We recognize general excise tax gross, with the amounts billed to tenants and customers recorded in other property income and the related taxes paid as rental expense. The general excise tax included in other income was $3.4 million, $3.5 million and $3.3 million for the years ended December 31, 2014, 2013 and 2012, respectively. For a tenant to terminate its lease agreement prior to the end of the agreed term, we may require that they pay a fee to cancel the lease agreement. Lease termination fees for which the tenant has relinquished control of the space are generally recognized on the termination date. When a lease is terminated early but the tenant continues to control the space under a modified lease agreement, the lease termination fee is generally recognized evenly over the remaining term of the modified lease agreement.
	We recognize revenue on the hotel portion of our mixed-use property from the rental of hotel rooms and guest services when the rooms are occupied and services have been provided. Food and beverage sales are recognized when the customer has been served or at the time the transaction occurs. Revenue from room rental is included in rental revenue on the statement of income. Revenue from other sales and services provided is included in other property income on the statement of income.
	We make estimates of the collectability of our accounts receivable related to minimum rents, straight-line rents, expense reimbursements and other revenue. Accounts receivable and deferred rent receivable are carried net of this allowance for doubtful accounts. We generally do not require collateral or other security from our tenants, other than letters of credit or security deposits. Our determination as to the collectability of accounts receivable and correspondingly, the adequacy of this allowance, is based primarily upon evaluations of individual receivables, current economic conditions, historical experience and other relevant factors. The allowance for doubtful accounts is increased or decreased through bad debt expense. In some cases, primarily relating to straight-line rents, the collection of these amounts extends beyond one year. Our experience relative to unbilled straight-line rents is that a portion of the amounts otherwise recognizable as revenue is never billed to or collected from tenants due to early lease terminations, lease modifications, bankruptcies and other factors. Accordingly, the extended collection period for straight-line rents along with our evaluation of tenant credit risk may result in the nonrecognition of a portion of straight-line rental income until the collection of such income is reasonably assured. If our evaluation of tenant credit risk changes indicating more straight-line revenue is reasonably collectible than previously estimated and realized, the additional straight-line rental income is recognized as revenue. If our evaluation of tenant credit risk changes indicating a portion of realized straight-line rental income is no longer collectible, a reserve and bad debt expense is recorded. At December 31, 2014 and December 31, 2013, our allowance for doubtful accounts was $0.8 million and $1.0 million, respectively, and our allowance for deferred rent receivables was $1.2 million and $1.2 million, respectively. Total bad debt expense was $0.2 million, $0.1 million and $0.6 million for the years ended December 31, 2014, 2013 and 2012, respectively.
	We recognize gains on sales of properties upon the closing of the transaction with the purchaser. Gains on properties sold are recognized using the full accrual method when (1) the collectability of the sales price is reasonably assured, (2) we are not obligated to perform significant activities after the sale, (3) the initial investment from the buyer is sufficient and (4) other profit recognition criteria have been satisfied. Gains on sales of properties may be deferred in whole or in part until the requirements for gain recognition have been met.
Real Estate	Real Estate
	Land, buildings and improvements are recorded at cost. Depreciation is computed using the straight-line method. Estimated useful lives range generally from 30 years to a maximum of 40 years on buildings and major improvements. Minor improvements, furniture and equipment are capitalized and depreciated over useful lives ranging from 3 years to 15 years. Maintenance and repairs that do not improve or extend the useful lives of the related assets are charged to operations as incurred. Tenant improvements are capitalized and depreciated over the life of the related lease or their estimated useful life, whichever is shorter. If a tenant vacates its space prior to the contractual termination of its lease, the undepreciated balance of any tenant improvements are written off if they are replaced or have no future value. For the years ended December 31, 2014, 2013 and 2012, real estate depreciation expense was $56.0 million, $52.0 million and $47.8 million, respectively, including amounts from discontinued operations.
	Acquisitions of properties are accounted for in accordance with the authoritative accounting guidance on acquisitions and business combinations. Our methodology of allocating the cost of acquisitions to assets acquired and liabilities assumed is based on estimated fair values, replacement cost and appraised values. When we acquire operating real estate properties, the purchase price is allocated to land and buildings, intangibles such as in-place leases, and to current assets and liabilities acquired, if any. Such valuations include a consideration of the noncancelable terms of the respective leases as well as any applicable renewal periods. The fair values associated with below market renewal options are determined based on a review of several qualitative and quantitative factors on a lease-by-lease basis at acquisition to determine whether it is probable that the tenant would exercise its option to renew the lease agreement. These factors include: (1) the type of tenant in relation to the property it occupies, (2) the quality of the tenant, including the tenant's long term business prospects and (3) whether the fixed rate renewal option was sufficiently lower than the fair rental of the property at the date the option becomes exercisable such that it would appear to be reasonably assured that the tenant would exercise the option to renew. The value allocated to in-place leases is amortized over the related lease term and reflected as depreciation and amortization in the statement of income.
	The value of above and below market leases associated with the original noncancelable lease terms are amortized to rental income over the terms of the respective noncancelable lease periods and are reflected as either an increase (for below market leases) or a decrease (for above market leases) to rental income in the statement of income. The value of the leases associated with below market lease renewal options that are likely to be exercised are amortized to rental income over the respective renewal periods. If a tenant vacates its space prior to contractual termination of its lease or the lease is not renewed, the unamortized balance of any in-place lease value is written off to rental income and amortization expense. Acquisition-related expenses are expensed in the period incurred.
Capitalized Costs	Capitalized Costs
	We capitalize certain costs related to the development and redevelopment of real estate including pre-construction costs, real estate taxes, insurance and construction costs and salaries and related costs of personnel directly involved. Additionally, we capitalize interest costs related to development and significant redevelopment activities. Capitalization of these costs begins when the activities and related expenditures commence and cease when the project is substantially complete and ready for its intended use, at which time the project is placed in service and depreciation commences. Additionally, we make estimates as to the probability of certain development and redevelopment projects being completed. If we determine that the completion of development or redevelopment is no longer probable, we expense all capitalized costs which are not recoverable.
Impairment of Long Lived Assets	Impairment of Long Lived Assets
	We review for impairment on a property by property basis. Impairment is recognized on properties held for use when the expected undiscounted cash flows for a property are less than its carrying amount at which time the property is written-down to fair value. Properties held for sale are recorded at the lower of the carrying amount or the expected sales price less costs to sell.
Financial Instruments	Financial Instruments
	The estimated fair values of financial instruments are determined using available market information and appropriate valuation methods. Considerable judgment is necessary to interpret market data and develop estimated fair values. The use of different market assumptions or estimation methods may have a material effect on the estimated fair value amounts. Accordingly, estimated fair values are not necessarily indicative of the amounts that could be realized in current market exchanges.
Derivative Instruments	Derivative Instruments
	At times, we may use derivative instruments to manage exposure to variable interest rate risk. We may enter into interest rate swaps to manage our exposure to variable interest rate risk. If and when we enter into derivative instruments, we ensure that such instruments qualify as cash flow hedges and would not enter into derivative instruments for speculative purposes.
	Any interest rate swaps associated with our cash flow hedges are recorded at fair value on a recurring basis. We assess effectiveness of our cash flow hedges both at inception and on an ongoing basis. The effective portion of changes in fair value of the interest rate swaps associated with our cash flow hedges is recorded in accumulated other comprehensive income (loss) and is subsequently reclassified into interest expense as interest is incurred on the related variable rate debt. Our cash flow hedges become ineffective if critical terms of the hedging instrument and the debt instrument do not perfectly match such as notional amounts, settlement dates, reset dates, calculation period and LIBOR rate. In addition, we evaluate the default risk of the counterparty by monitoring the credit worthiness of the counterparty. When ineffectiveness exists, the ineffective portion of changes in fair value of the interest rate swaps associated with our cash flow hedges is recognized in earnings in the period affected. We had no hedging instruments outstanding during 2013 or 2012. Concurrent with the closing of the amended and restated credit facility, we entered into an interest rate swap agreement that is intended to fix the interest rate associated with the term loan at approximately 3.08% through its maturity date and extension options, subject to adjustments based on our consolidated leverage ratio (see Note 9).
Cash and Cash Equivalents	Cash and Cash Equivalents
	We define cash and cash equivalents as cash on hand, demand deposits with financial institutions and short term liquid investments with an initial maturity of less than 3 months. Cash balances in individual banks may exceed the federally insured limit of $250,000 by the Federal Deposit Insurance Corporation (the "FDIC"). No losses have been experienced related to such accounts.
Restricted Cash	Restricted Cash
	Restricted cash consists of amounts held by lenders to provide for future real estate tax expenditures, insurance expenditures and reserves for capital improvements. Activity for accounts related to real estate tax and insurance expenditures is classified as operating activities in the statement of cash flows. Changes in reserves for capital improvements are classified as investing activities in the statement of cash flows.
Marketable Securities	Marketable Securities
	Our portfolio of marketable securities was comprised of debt securities that are classified as trading. Trading securities are presented on our consolidated balance sheets at fair value at the end of each reporting period. Gains and losses resulting from the mark-to-market of these securities were recognized as unrealized and realized gains or losses in income.
Other Assets	Other Assets
	Other assets consist primarily of lease costs, lease incentives, acquired in-place leases, acquired above market leases and debt issuance costs. Capitalized lease costs are direct costs incurred which were essential to originate a lease and would not have been incurred had the leasing transaction not taken place and include third party commissions related to obtaining a lease. Capitalized lease costs are amortized over the life of the related lease and included in depreciation and amortization expense on the statement of income. If a tenant vacates its space prior to the contractual termination of its lease, the unamortized balance of any lease costs are written off. We view these lease costs as part of the up-front initial investment we made in order to generate a long-term cash inflow. Therefore, we classify cash outflows for lease costs as an investing activity in our consolidated statements of cash flows.
	Costs related to the issuance of debt instruments are capitalized and are amortized as interest expense over the estimated life of the related issue using the straight-line method which approximates the effective interest method. If a debt instrument is paid off prior to its original maturity date, the unamortized balance of debt issuance costs are written off to interest expense or, if significant, included in “early extinguishment of debt.”
Variable Interest Entities	Variable Interest Entities
	Certain entities that do not have sufficient equity at risk for the entity to finance its activities without additional subordinated financial support from other parties or in which equity investors do not have the characteristics of a controlling financial interest qualify as variable interest entities (“VIEs”). VIEs are required to be consolidated by their primary beneficiary. The primary beneficiary of a VIE is the party that has a controlling interest in the VIE. Identifying the party with the controlling interest requires a focus on which entity has the power to direct the activities of the VIE that most significantly impact the VIE's economic performance and (1) the obligation to absorb the expected losses of the VIE or (2) the right to receive the benefits from the VIE.
Stock-Based Compensation	Stock-Based Compensation
	We grant stock-based compensation awards to our employees and directors typically in the form of restricted shares of common stock, options to purchase common stock and/or shares of common stock. We measure stock-based compensation expense based on the fair value of the award on the grant date and recognize the expense ratably over the vesting period.
Deferred Compensation	Deferred Compensation
	Our Operating Partnership has adopted the American Assets Trust Executive Deferral Plan V (“EDP V”) and the American Assets Trust Executive Deferral Plan VI (“EDP VI”). These plans were adopted by our Operating Partnership as successor plans to those deferred compensation plans maintained by American Assets Inc. ("AAI") in which certain employees of AAI, who were transferred to us in connection with the Offering (the “Transferred Participants”), participated prior to the Offering. EDP V and EDP VI contain substantially the same terms and conditions as these predecessor plans. AAI transferred to our Operating Partnership the Transferred Participants' account balances under the predecessor plans. These transferred account balances represent amounts deferred by the Transferred Participants prior to the Offering while they were employed by AAI.
	At the time eligible participants defer compensation, we record compensation cost and a corresponding deferred compensation plan liability, which is included in other liabilities and deferred credits on our consolidated balance sheets. This liability is adjusted to fair value at the end of each accounting period based on the performance of the benchmark funds selected by each participant, and the impact of adjusting the liability to fair value is recorded as an increase or decrease to compensation cost.
Income Taxes	Income Taxes
	We elected to be taxed as a REIT under the Internal Revenue Code of 1986, as amended (the “Code”) commencing with the taxable year ending December 31, 2011. To maintain our qualification as a REIT, we are required to distribute at least 90% of our REIT taxable income to our stockholders and meet the various other requirements imposed by the Code relating to such matters as operating results, asset holdings, distribution levels and diversity of stock ownership. Provided we maintain our qualification for taxation as a REIT, we are generally not subject to corporate level income tax on the earnings distributed currently to our stockholders that we derive from our REIT qualifying activities. If we fail to maintain our qualification as a REIT in any taxable year, and are unable to avail ourselves of certain savings provisions set forth in the Code, all of our taxable income would be subject to federal income tax at regular corporate rates, including any applicable alternative minimum tax. We are subject to certain state and local income taxes.
	We, together with one of our subsidiaries, have elected to treat such subsidiary as a taxable REIT subsidiary (a “TRS”) for federal income tax purposes. Certain activities that we undertake must be conducted by a TRS, such as non-customary services for our tenants, and holding assets that we cannot hold directly. A TRS is subject to federal and state income taxes.
Segment Information	Segment Information
	Segment information is prepared on the same basis that our management reviews information for operational decision-making purposes. We operate in four business segments: the acquisition, redevelopment, ownership and management of retail real estate, office real estate, multifamily real estate and mixed-use real estate. The products for our retail segment primarily include rental of retail space and other tenant services, including tenant reimbursements, parking and storage space rental. The products for our office segment primarily include rental of office space and other tenant services, including tenant reimbursements, parking and storage space rental. The products for our multifamily segment include rental of apartments and other tenant services. The products of our mixed-use segment include rental of retail space and other tenant services, including tenant reimbursements, parking and storage space rental and operation of a 369-room all-suite hotel.
Recent Accounting Pronouncements	Recent Accounting Pronouncements
	In February 2013, the FASB issued ASU 2013-2, Comprehensive Income (Topic 220): Reporting Amounts Reclassified Out of Accumulated Other Comprehensive Income. ASU 2013-2 requires entities to disclose certain information relating to amounts reclassified out of accumulated other comprehensive income. This pronouncement became effective for us in the first quarter of 2013 and did not have a significant impact on our consolidated financial statements.
	In April 2014, the FASB issued ASU 2014-08, Presentation of Financial Statements (Topic 205) and Property, Plant, and Equipment (Topic 360): Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity. ASU 2014-08 revises the definition of a discontinued operation to a disposal, sale or held-for-sale component or group of components that represents a strategic shift that will have a major effect on an entity's operations and financial results. This pronouncement is effective in 2015, however, calendar year-end companies may early adopt during the first quarter of 2014. We have chosen to early adopt this pronouncement and it became effective for us in the first quarter of 2014. This pronouncement did not have a significant impact on our consolidated financial statements.
	In May 2014, the FASB issued Update No. 2014-09, Revenue from Contracts with Customers. Update No. 2014-09 establishes that companies may recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. This pronouncement is effective for annual reporting periods beginning after December 15, 2016, including interim reporting periods within that reporting period; early adoption is not permitted. We are in the process of evaluating the impact this pronouncement will have on our consolidated financial statements.
Fair Value Measurements	FAIR VALUE OF FINANCIAL INSTRUMENTS
	A fair value measurement is based on the assumptions that market participants would use in pricing an asset or liability. The hierarchy for inputs used in measuring fair value is as follows:
	1	Level 1 Inputs—quoted prices in active markets for identical assets or liabilities
	2	Level 2 Inputs—observable inputs other than quoted prices in active markets for identical assets and liabilities
	3	Level 3 Inputs—unobservable inputs
	In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, for disclosure purposes, the level within which the fair value measurement is categorized is based on the lowest level input that is significant to the fair value measurement.

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Summary of Properties Owned	A summary of the properties owned by us is as follows:
	Retail
	Carmel Country Plaza	Del Monte Center
	Carmel Mountain Plaza	Geary Marketplace
	South Bay Marketplace	The Shops at Kalakaua
	Rancho Carmel Plaza	Waikele Center
	Lomas Santa Fe Plaza	Alamo Quarry Market
	Solana Beach Towne Centre
	Office
	Torrey Reserve Campus	Lloyd District Portfolio
	Solana Beach Corporate Centre	City Center Bellevue
	The Landmark at One Market
	One Beach Street
	First & Main
	Multifamily
	Loma Palisades
	Imperial Beach Gardens
	Mariner's Point
	Santa Fe Park RV Resort
	Mixed-Use
	Waikiki Beach Walk Retail and Embassy Suites™ Hotel
	Held for Development and Construction in Progress
	Solana Beach Corporate Centre – Land
	Solana Beach – Highway 101 – Land
	Sorrento Pointe – Land
	Torrey Reserve – Construction in Progress
	Lloyd District Portfolio – Construction in Progress
	A summary of our real estate investments is as follows (in thousands):
		Retail			Office			Multifamily			Mixed-Use			Total
	December 31, 2014
	Land	$	248,386		$	143,575		$	25,507		$	76,635		$	494,103
	Buildings	500,088			621,343			42,270			125,798			1,289,499
	Land improvements	39,999			8,273			3,085			2,363			53,720
	Tenant improvements	50,504			56,127			—			1,679			108,310
	Furniture, fixtures, and equipment	491			750			5,832			5,383			12,456
	Construction in progress	5,327			31,878			141,205			326			178,736			(1)
		844,795			861,946			217,899			212,184			2,136,824
	Accumulated depreciation	(205,339		)	(104,092		)	(35,431		)	(16,562		)	(361,424		)
	Net real estate	$	639,456		$	757,854		$	182,468		$	195,622		$	1,775,400
	December 31, 2013
	Land	$	248,008		$	143,575		$	25,507		$	76,635		$	493,725
	Buildings	499,091			618,077			42,270			123,142			1,282,580
	Land improvements	39,892			7,528			3,010			2,363			52,793
	Tenant improvements	46,649			51,016			—			1,697			99,362
	Furniture, fixtures, and equipment	489			517			5,482			10,080			16,568
	Construction in progress	2,673			14,189			32,252			1,275			50,389			(1)
		836,802			834,902			108,521			215,192			1,995,417
	Accumulated depreciation	(185,095		)	(84,012		)	(33,909		)	(15,565		)	(318,581		)
	Net real estate	$	651,707		$	750,890		$	74,612		$	199,627		$	1,676,836
	(1) Land related to held for development and construction in progress is included in the Held for Development and Construction in Progress classifications on the consolidated balance sheets.
Consolidated Statements of Cash Flows-Supplemental Disclosures	The following table provides supplemental disclosures related to the Consolidated Statements of Cash Flows (in thousands):
		Year Ended December 31,
		2014			2013			2012
	Supplemental cash flow information
	Total interest costs incurred	$	58,455		$	60,133		$	58,074
	Interest capitalized	$	5,490		$	2,113		$	746
	Interest expense	$	52,965		$	58,020		$	57,328
	Cash paid for interest, net of amounts capitalized (including discontinued operations)	$	48,032		$	54,345		$	55,349
	Cash paid for income taxes	$	404		$	901		$	1,239
	Supplemental schedule of noncash investing and financing activities
	Accounts payable and accrued liabilities for construction in progress	$	9,908		$	5,001		$	4,944
	Accrued leasing commissions	$	763		$	1,385		$	(782	)
	Accrued placement fees for senior guaranteed notes payable	$	750		$	—		$	—
	Reduction to capital for prepaid equity financing costs	$	40		$	437		$	—

Real_Estate_Tables

Real Estate (Tables)	12 Months Ended
	Dec. 31, 2014
Real Estate [Abstract]
Summary of Real Estate Investments	A summary of the properties owned by us is as follows:
	Retail
	Carmel Country Plaza	Del Monte Center
	Carmel Mountain Plaza	Geary Marketplace
	South Bay Marketplace	The Shops at Kalakaua
	Rancho Carmel Plaza	Waikele Center
	Lomas Santa Fe Plaza	Alamo Quarry Market
	Solana Beach Towne Centre
	Office
	Torrey Reserve Campus	Lloyd District Portfolio
	Solana Beach Corporate Centre	City Center Bellevue
	The Landmark at One Market
	One Beach Street
	First & Main
	Multifamily
	Loma Palisades
	Imperial Beach Gardens
	Mariner's Point
	Santa Fe Park RV Resort
	Mixed-Use
	Waikiki Beach Walk Retail and Embassy Suites™ Hotel
	Held for Development and Construction in Progress
	Solana Beach Corporate Centre – Land
	Solana Beach – Highway 101 – Land
	Sorrento Pointe – Land
	Torrey Reserve – Construction in Progress
	Lloyd District Portfolio – Construction in Progress
	A summary of our real estate investments is as follows (in thousands):
		Retail			Office			Multifamily			Mixed-Use			Total
	December 31, 2014
	Land	$	248,386		$	143,575		$	25,507		$	76,635		$	494,103
	Buildings	500,088			621,343			42,270			125,798			1,289,499
	Land improvements	39,999			8,273			3,085			2,363			53,720
	Tenant improvements	50,504			56,127			—			1,679			108,310
	Furniture, fixtures, and equipment	491			750			5,832			5,383			12,456
	Construction in progress	5,327			31,878			141,205			326			178,736			(1)
		844,795			861,946			217,899			212,184			2,136,824
	Accumulated depreciation	(205,339		)	(104,092		)	(35,431		)	(16,562		)	(361,424		)
	Net real estate	$	639,456		$	757,854		$	182,468		$	195,622		$	1,775,400
	December 31, 2013
	Land	$	248,008		$	143,575		$	25,507		$	76,635		$	493,725
	Buildings	499,091			618,077			42,270			123,142			1,282,580
	Land improvements	39,892			7,528			3,010			2,363			52,793
	Tenant improvements	46,649			51,016			—			1,697			99,362
	Furniture, fixtures, and equipment	489			517			5,482			10,080			16,568
	Construction in progress	2,673			14,189			32,252			1,275			50,389			(1)
		836,802			834,902			108,521			215,192			1,995,417
	Accumulated depreciation	(185,095		)	(84,012		)	(33,909		)	(15,565		)	(318,581		)
	Net real estate	$	651,707		$	750,890		$	74,612		$	199,627		$	1,676,836
	(1) Land related to held for development and construction in progress is included in the Held for Development and Construction in Progress classifications on the consolidated balance sheets.
Allocation of Purchase Price	The allocation of the purchase price for each of One Beach Street, City Center Bellevue and Geary Marketplace is as follows (in thousands):
		One Beach Street			City Center Bellevue			Geary Marketplace			Total
	Land	$	15,332		$	25,135		$	8,239		$	48,706
	Building	16,764			185,653			11,179			213,596
	Land improvements	30			154			704			888
	Tenant improvements	1,223			5,191			470			6,884
	Total real estate	33,349			216,133			20,592			270,074
	Lease intangibles	4,141			11,870			1,017			17,028
	Prepaid expenses and other assets	1			2,596			414			3,011
	Total assets	$	37,491		$	230,599		$	22,023		$	290,113
	Accounts payable and accrued expenses	$	94		$	456		$	—		$	550
	Security deposits payable	75			740			—			815
	Lease intangibles	1,382			8,733			1,124			11,239
	Other liabilities and deferred credits	22			497			—			519
	Total liabilities	$	1,573		$	10,426		$	1,124		$	13,123
Net Revenue and Net Income from Discontinued Operations	Net revenue and net income from the property's discontinued operations were as follows (in thousands):
		Year Ended December 31,
		2014			2013			2012
	Net revenue from discontinued operations	$	—		$	—		$	6,734
	Results from discontinued operations
	Income from discontinued operations	—			—			932
	Gain on sale of real estate from discontinued operations	—			—			36,720
	Total income from discontinued operations	$	—		$	—		$	37,652

Acquired_InPlace_Leases_and_Ab1

Acquired In-Place Leases and Above/Below Market Leases (Tables)	12 Months Ended
	Dec. 31, 2014
Leases [Abstract]
Schedule of acquired lease intangibles included in other assets and other liabilities	Increases (decreases) in net income as a result of amortization of our in-place leases, above market leases and below market leases are as follows (in thousands):
		Year Ended December 31,
		2014			2013			2012
	Amortization of in-place leases	$	(5,903	)	$	(9,120	)	$	(10,248	)
	Amortization of above market leases	(2,296		)	(4,052		)	(5,739		)
	Amortization of below market leases	5,057			6,440			5,502
	Net loss	$	(3,142	)	$	(6,732	)	$	(10,485	)
	The following summarizes our acquired lease intangibles, which are included in other assets and other liabilities and deferred credits (in thousands):
		December 31, 2014			December 31, 2013
	In-place leases	$	53,967		$	62,813
	Accumulated amortization	(35,336		)	(38,279		)
	Above market leases	22,500			28,279
	Accumulated amortization	(17,397		)	(20,880		)
	Acquired lease intangible assets, net	$	23,734		$	31,933
	Below market leases	$	70,013		$	76,502
	Accumulated accretion	(27,161		)	(28,592		)
	Acquired lease intangible liabilities, net	$	42,852		$	47,910
Future Amortization for Acquired In-Place Leases	As of December 31, 2014, the amortization for acquired leases during the next five years and thereafter, assuming no early lease terminations, is as follows (in thousands):
		In-Place			Above Market			Below Market
		Leases			Leases			Leases
	Year Ending December 31,
	2015	$	4,744		$	1,752		$	4,667
	2016	3,954			1,263			4,525
	2017	3,189			932			4,169
	2018	1,893			628			3,649
	2019	1,452			318			3,560
	Thereafter	3,399			210			22,282
		$	18,631		$	5,103		$	42,852

Fair_Value_of_Financial_Instru1

Fair Value of Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Financial liabilities measured at fair value on recurring basis	A summary of our financial liabilities that are measured at fair value on a recurring basis by level within the fair value hierarchy is as follows (in thousands):
		December 31, 2014											December 31, 2013
		Level 1		Level 2			Level 3			Total			Level 1		Level 2		Level 3		Total
	Deferred compensation liability	$	—	$	981		$	—		$	981		$	—	$	769	$	—	$	769
	Interest rate swap liability	$	—	$	1,448		$	—		$	1,448		$	—	$	—	$	—	$	—
Carrying amount and fair value of financial instruments	A summary of the carrying amount and fair value of our financial instruments, all of which are based on Level 2 inputs, is as follows (in thousands):
		December 31, 2014							December 31, 2013
		Carrying Value			Fair Value				Carrying Value			Fair Value
	Secured notes payable	$	812,811		$	850,475			$	952,174		$	990,296
	Term loan	$	100,000		$	100,000			$	—		$	—
	Senior guaranteed notes, Series A	$	150,000		$	154,560			$	—		$	—
	Line of credit	$	—		$	—			$	93,000		$	93,000

Other_Assets_Tables

Other Assets (Tables)	12 Months Ended
	Dec. 31, 2014
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Components of Prepaid Expenses and Other Assets	Other assets consist of the following (in thousands):
		31-Dec-14		31-Dec-13
	Leasing commissions, net of accumulated amortization of $20,659 and $19,606 respectively	$	19,484	$	18,071
	Acquired above market leases, net	5,103		7,399
	Acquired in-place leases, net	18,631		24,534
	Lease incentives, net of accumulated amortization of $2,960 and $2,590, respectively	740		1,110
	Other intangible assets, net of accumulated amortization of $1,590 and $1,554, respectively	453		655
	Debt issuance costs, net of accumulated amortization of $4,147 and $2,985, respectively	5,361		2,632
	Prepaid expenses, deposits and other	3,629		3,269
	Total other assets	$	53,401	$	57,670

Other_Liabilities_and_Deferred1

Other Liabilities and Deferred Credits (Tables)	12 Months Ended
	Dec. 31, 2014
Other Liabilities Disclosure [Abstract]
Other liabilities and deferred credits	Other liabilities and deferred credits consist of the following (in thousands):
		31-Dec-14		31-Dec-13
	Acquired below market leases, net	$	42,852	$	47,910
	Prepaid rent and deferred revenue	7,288		7,506
	Interest rate swap liability	1,448		—
	Straight-line rent liability	2,533		1,145
	Deferred rent expense	584		829
	Deferred compensation	981		769
	Deferred tax liability	219		233
	Other liabilities	88		73
	Total other liabilities and deferred credits	$	55,993	$	58,465

Debt_Tables

Debt (Tables)	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Summary of total secured notes payable outstanding	The following is a summary of the Operating Partnership's total secured notes payable outstanding as of December 31, 2014 and December 31, 2013 (in thousands):
	Description of Debt	Principal Balance as of						Stated Interest Rate		Stated Maturity Date
		31-Dec-14			31-Dec-13			as of December 31, 2014
	Waikele Center (1)(2)	—			140,700			—		November 1, 2014
	The Shops at Kalakaua (1)(3)	19,000			19,000			5.45	%	May 1, 2015
	The Landmark at One Market (1)(5)	133,000			133,000			5.61	%	July 5, 2015
	Del Monte Center (1)(4)	82,300			82,300			4.93	%	July 8, 2015
	First & Main (1)	84,500			84,500			3.97	%	July 1, 2016
	Imperial Beach Gardens (1)	20,000			20,000			6.16	%	September 1, 2016
	Mariner’s Point (1)	7,700			7,700			6.09	%	September 1, 2016
	South Bay Marketplace (1)	23,000			23,000			5.48	%	February 10, 2017
	Waikiki Beach Walk—Retail (1)	130,310			130,310			5.39	%	July 1, 2017
	Solana Beach Corporate Centre III-IV (6)	36,376			36,804			6.39	%	August 1, 2017
	Loma Palisades (1)	73,744			73,744			6.09	%	July 1, 2018
	One Beach Street (1)	21,900			21,900			3.94	%	April 1, 2019
	Torrey Reserve—North Court (6)	21,075			21,377			7.22	%	June 1, 2019
	Torrey Reserve—VCI, VCII, VCIII (6)	7,101			7,200			6.36	%	June 1, 2020
	Solana Beach Corporate Centre I-II (6)	11,302			11,475			5.91	%	June 1, 2020
	Solana Beach Towne Centre (6)	37,675			38,249			5.91	%	June 1, 2020
	City Center Bellevue (1)	111,000			111,000			3.98	%	November 1, 2022
	Total	819,983			962,259
	Unamortized fair value adjustment	(7,172		)	(10,085		)
	Total Secured Notes Payable	$	812,811		$	952,174
	-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	Loan repaid in full, without premium or penalty, on February 6, 2015.
	-5	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.
	-6	Principal payments based on a 30-year amortization schedule.
Scheduled principal payments on notes payable	Scheduled principal payments on secured and unsecured notes payable as of December 31, 2014 are as follows (in thousands):
	2015	$	235,980
	2016	113,974
	2017	190,139
	2018	75,224
	2019	142,662
	Thereafter	312,004
		$	1,069,983

Derivative_and_Hedging_Tables

Derivative and Hedging (Tables)	12 Months Ended
	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Interest Rate Derivatives	The following is a summary of the terms of the interest rate swap as of December 31, 2014 (dollars in thousands):
	Swap Counterparty	Notional Amount	Effective Date	Maturity Date	Fair Value
	Bank of America, N.A.	$100,000	1/9/14	1/9/19	$	1,448

Equity_of_American_Assets_Trus1

Equity of American Assets Trust, Inc. (Tables)	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Dividends declared and paid on shares of common stock and noncontrolling common units	The following table lists the dividends declared and paid on our shares of common stock and Noncontrolling Common Units for the years ended December 31, 2014, 2013 and 2012:
	Period		Amount per Share/Unit				Period Covered		Dividend Paid Date
	First Quarter 2012		$	0.21			January 1, 2012 to March 31, 2012		March 30, 2012
	Second Quarter 2012		$	0.21			April 1, 2012 to June 30, 2012		June 29, 2012
	Third Quarter 2012		$	0.21			July 1, 2012 to September 30, 2012		September 28, 2012
	Fourth Quarter 2012		$	0.21			October 1, 2012 to December 31, 2012		December 28, 2012
	First Quarter 2013		$	0.21			January 1, 2013 to March 31, 2013		March 29, 2013
	Second Quarter 2013		$	0.21			April 1, 2013 to June 30, 2013		June 28, 2013
	Third Quarter 2013		$	0.21			July 1, 2013 to September 30, 2013		September 27, 2013
	Fourth Quarter 2013		$	0.22			October 1, 2013 to December 31, 2013		December 27, 2013
	First Quarter 2014		$	0.22			January 1, 2014 to March 31, 2014		March 28, 2014
	Second Quarter 2014		$	0.22			April 1, 2014 to June 30, 2014		June 27, 2014
	Third Quarter 2014		$	0.22			July 1, 2014 to September 30, 2014		September 26, 2014
	Fourth Quarter 2014		$	0.2325			October 1, 2014 to December 31, 2014		December 26, 2014
Summary of income tax status of dividends per share paid	A summary of the income tax status of dividends per share paid is as follows:
			Year Ended December 31,
			2014							2013					2012
			Per Share				%			Per Share			%		Per Share		%
	Ordinary income		$	0.61			68.9	%		$	0.83		97.6	%	$	0.56	66.7	%
	Return of capital		0.28				31.1	%		0.02			2.4	%	0.28		33.3	%
	Total		$	0.89			100	%		$	0.85		100	%	$	0.84	100	%
Schedule of restricted common stock	The following shares of restricted common stock have been issued as of December 31, 2014:
	Grant	Price at Grant Date	Number
	January 19, 2012 (1)	$11.91 - $12.61	2,000
	July 10, 2012 (2)	$25.05	8,015
	July 13, 2013 (2)	$31.97	5,004
	March 25, 2014 (3)	$28.89 - $31.25	112,119
	June 17, 2014 (4)	$34.10	5,864
	December 1, 2014 (5)	$36.28 - $36.32	98,765
	(1) Restricted common stock issued to certain of the company's senior management and other employees, which are subject to performance-based vesting. These shares vest in two substantially equal installments, with the first installment vested on the third anniversary of the date of grant and the second installment vesting on the fourth anniversary of the date of grant, subject to the employee's continued employment on those dates.
	(2) Restricted common stock issued to members of the company's non-employee directors. These awards of restricted stock vest ratably as to one-third of the shares granted on each of the first three anniversaries of the date of grant, subject to the director's continued service on our Board of Directors.
	(3) Restricted common stock issued to certain of the company's senior management and other employees, which are subject to pre-defined market specific performance criteria based vesting. Up to one-third of the shares of restricted stock may vest on each of November 30, 2014, 2015 and 2016, subject to the employee's continued employment on those dates.
	(4) Restricted common stock issued to members of the company's non-employee directors. These awards of restricted stock will vest subject to the director's continued service on the Board of Directors on the earlier of (i) the one year anniversary of the date of grant or (ii) the date of the next annual meeting of our stockholders, if such non-employee director continues his or her service on the Board of Directors until the next annual meeting of stockholders, but not thereafter, pursuant to our independent director compensation policy.
	(5) Restricted common stock issued to certain of the company's senior management and other employees, which are subject to pre-defined market specific performance criteria based vesting. Up to one-third of the shares of restricted stock may vest on each of November 30, 2015, 2016 and 2017, subject to the employee's continued employment on those dates.
Activity of restricted stock awards	The following table summarizes the activity of non-vested restricted stock awards during the year ended December 31, 2014:
		2014
		Units			Weighted Average Grant Date Fair Value
	Balance at beginning of year	629,058			$	15.58
	Granted	216,748			32.96
	Vested	(351,075	)		17.22
	Forfeited	(1,192	)		29.83
	Balance at end of year	493,539			$	22.01
Computation of basic and diluted EPS	The computation of basic and diluted EPS is presented below (dollars in thousands, except share and per share amounts):
		Year Ended December 31,
		2014				2013				2012
	NUMERATOR
	Income from continuing operations	$	31,145			$	22,594			$	13,949
	Less: Net income attributable to restricted shares	(374		)		(536		)		(529		)
	Less: Income from continuing operations attributable to unitholders in the Operating Partnership	(9,015		)		(6,838		)		(4,239		)
	Income from continuing operations attributable to American Assets Trust, Inc. common stockholders—basic	21,756				15,220				9,181
	Plus: Results from discontinued operations attributable to American Assets Trust, Inc. common stockholders	—				—				25,757
	Net income attributable to common stockholders—basic	$	21,756			$	15,220			$	34,938
	Income from continuing operations attributable to American Assets Trust, Inc. common stockholders—basic	$	21,756			$	15,220			$	9,181
	Plus: Income from continuing operations attributable to unitholders in the Operating Partnership	9,015				6,838				4,239
	Income from continuing operations attributable to common stockholders—diluted	30,771				22,058				13,420
	Plus: Results from discontinued operations attributable to American Assets Trust, Inc. common stockholders	—				—				25,757
	Plus: Results from discontinued operations attributable to unitholders in the Operating Partnership	—				—				11,895
	Net income attributable to common stockholders—diluted	$	30,771			$	22,058			$	51,072
	DENOMINATOR
	Weighted average common shares outstanding—basic	42,041,126				39,539,457				38,736,113
	Effect of dilutive securities—conversion of Operating Partnership units	17,906,348				17,976,353				18,317,796
	Weighted average common shares outstanding—diluted	59,947,474				57,515,810				57,053,909
	Earnings per common share—basic
	Continuing operations	$	0.52			$	0.38			$	0.24
	Discontinued operations	—				—				0.66
		$	0.52			$	0.38			$	0.9
	Earnings per common share—diluted
	Continuing operations	$	0.51			$	0.38			$	0.24
	Discontinued operations	—				—				0.66
		$	0.51			$	0.38			$	0.9

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income tax provision	The income tax provision included in other income (expense) on the consolidated statement of income is as follows (in thousands):
		Year Ended December 31, 2014			Year Ended December 31, 2013			Year Ended December 31, 2012
	Current:
	Federal	$	190		$	370		$	361
	State	284			362			335
	Deferred:
	Federal	$	—		$	(47	)	$	118
	State	(14		)	(40		)	202
	Provision for income taxes	$	460		$	645		$	1,016

Commitments_and_Contingencies_1

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Current minimum annual payments under the leases	Current minimum annual payments under the leases are as follows, as of December 31, 2014 (in thousands):
	2015	$	2,636
	2016	2,682		(1)
	2017	2,686		(2)
	2018	2,686
	2019	2,686
	Thereafter	23,856
	Total	$	37,232
	-1	Lease payments on The Landmark at One Market lease will be equal to fair rental value from July 2016 through the end of the options lease term. In the table, we have shown the option lease payments for this period based on the stated rate for the month of June 2016 of $162,140.
	-2	Lease payments on the Waikiki Beach Walk lease will be equal to fair rental value from March 2017 through the end of the lease term. In the table, we have shown the lease payments for this period based on the stated rate for the month of February 2017 of $61,690.
	As of December 31, 2014, minimum future rentals from noncancelable operating leases before any reserve for uncollectible amounts and assuming no early lease terminations, at our office and retail properties and the retail portion of our mixed-use property are as follows for the years ended December 31 (in thousands):
	2015	$	159,988
	2016	144,660
	2017	128,865
	2018	96,844
	2019	69,309
	Thereafter	193,704
	Total	$	793,370

Operating_Leases_Tables

Operating Leases (Tables)	12 Months Ended
	Dec. 31, 2014
Leases, Operating [Abstract]
Current minimum future rentals under the leases	Current minimum annual payments under the leases are as follows, as of December 31, 2014 (in thousands):
	2015	$	2,636
	2016	2,682		(1)
	2017	2,686		(2)
	2018	2,686
	2019	2,686
	Thereafter	23,856
	Total	$	37,232
	-1	Lease payments on The Landmark at One Market lease will be equal to fair rental value from July 2016 through the end of the options lease term. In the table, we have shown the option lease payments for this period based on the stated rate for the month of June 2016 of $162,140.
	-2	Lease payments on the Waikiki Beach Walk lease will be equal to fair rental value from March 2017 through the end of the lease term. In the table, we have shown the lease payments for this period based on the stated rate for the month of February 2017 of $61,690.
	As of December 31, 2014, minimum future rentals from noncancelable operating leases before any reserve for uncollectible amounts and assuming no early lease terminations, at our office and retail properties and the retail portion of our mixed-use property are as follows for the years ended December 31 (in thousands):
	2015	$	159,988
	2016	144,660
	2017	128,865
	2018	96,844
	2019	69,309
	Thereafter	193,704
	Total	$	793,370

Component_of_Rental_Income_and1

Component of Rental Income and Expense (Tables)	12 Months Ended
	Dec. 31, 2014
Operating Leases, Income Statement, Lease Revenue [Abstract]
Principal components of rental income	The principal components of rental income are as follows (in thousands):
		Year Ended December 31,
		2014		2013		2012
	Minimum rents
	Retail	$	70,573	$	69,374	$	67,046
	Office	82,018		81,845		71,817
	Multifamily	15,732		14,926		13,796
	Mixed-Use	10,004		9,549		8,893
	Cost reimbursement	29,052		27,583		27,763
	Percentage rent	3,107		2,655		2,608
	Hotel revenue	33,911		35,137		31,729
	Other	1,681		1,688		1,597
	Total rental income	$	246,078	$	242,757	$	225,249
Principal components of rental expenses	The principal components of rental expenses are as follows (in thousands):
		Year Ended December 31,
		2014		2013		2012
	Rental operating	$	26,371	$	26,028	$	24,264
	Hotel operating	21,488		22,115		20,905
	Repairs and maintenance	10,600		10,514		9,452
	Marketing	1,623		1,547		1,266
	Rent	2,452		2,442		2,378
	Hawaii excise tax	3,981		4,153		3,813
	Management fees	1,752		1,809		2,011
	Total rental expenses	$	68,267	$	68,608	$	64,089

Other_Income_Expenses_Tables

Other Income (Expenses) (Tables)	12 Months Ended
	Dec. 31, 2014
Other Income and Expenses [Abstract]
Principal components of other income (expense), net	The principal components of other income (expense), net are as follows (in thousands):
		Year Ended December 31,
		2014			2013			2012
	Interest and investment income	$	155		$	148		$	336
	Income tax expense	(460		)	(645		)	(1,016		)
	Acquisition related expenses	—			—			(152		)
	Other non-operating income	746			10			203
	Total other income (expense)	$	441		$	(487	)	$	(629	)

Segment_Reporting_Tables

Segment Reporting (Tables)	12 Months Ended
	Dec. 31, 2014
Segment Reporting [Abstract]
Schedule of segments operating activity	The following table represents operating activity within our reportable segments (in thousands):
		Year Ended December 31,
		2014			2013			2012
	Total Retail
	Property revenue	$	96,140		$	93,449		$	91,991
	Property expense	(25,451		)	(23,900		)	(24,955		)
	Segment profit	70,689			69,549			67,036
	Total Office
	Property revenue	92,474			90,527			78,101
	Property expense	(27,003		)	(26,688		)	(23,780		)
	Segment profit	65,471			63,839			54,321
	Total Multifamily
	Property revenue	16,976			16,125			14,852
	Property expense	(6,099		)	(5,917		)	(5,914		)
	Segment profit	10,877			10,208			8,938
	Total Mixed-Use
	Property revenue	54,410			54,956			50,522
	Property expense	(32,678		)	(33,481		)	(31,465		)
	Segment profit	21,732			21,475			19,057
	Total segments’ profit	$	168,769		$	165,071		$	149,352
Reconciliation of segment profit to net income attributable to stockholders	The following table is a reconciliation of segment profit to net income attributable to stockholders (in thousands):
		Year Ended December 31,
		2014			2013			2012
	Total segments' profit	$	168,769		$	165,071		$	149,352
	General and administrative	(18,532		)	(17,195		)	(15,593		)
	Depreciation and amortization	(66,568		)	(66,775		)	(61,853		)
	Interest expense	(52,965		)	(58,020		)	(57,328		)
	Other income (expense), net	441			(487		)	(629		)
	Income from continuing operations	31,145			22,594			13,949
	Discontinued operations
	Income from discontinued operations	—			—			932
	Gain on sale of real estate property	—			—			36,720
	Results from discontinued operations	—			—			37,652
	Net income	31,145			22,594			51,601
	Net income attributable to restricted shares	(374		)	(536		)	(529		)
	Net income attributable to unitholders in the Operating Partnership	(9,015		)	(6,838		)	(16,134		)
	Net income attributable to American Assets Trust, Inc. stockholders	$	21,756		$	15,220		$	34,938
Net Real Estate and Secured note payable balances by Segments	The following table shows net real estate and secured note payable balances for each of the segments, along with their capital expenditures for each year (in thousands):
		December 31, 2014			December 31, 2013
	Net real estate
	Retail	$	639,456		$	651,707
	Office	757,854			750,890
	Multifamily	182,468			74,612
	Mixed-Use	195,622			199,627
		$	1,775,400		$	1,676,836
	Secured Notes Payable (1)
	Retail	$	161,975		$	303,249
	Office	426,254			427,256
	Multifamily	101,444			101,444
	Mixed-Use	130,310			130,310
		$	819,983		$	962,259
	Capital Expenditures (2)
	Retail	$	8,671		$	4,849
	Office	34,577			27,275
	Multifamily	101,392			24,641
	Mixed-Use	5,132			1,942
		$	149,772		$	58,707
	-1	Excludes unamortized fair market value adjustment of $7.2 million and $10.1 million as of December 31, 2014 and 2013, respectively.
	-2	Capital expenditures represent cash paid for capital expenditures during the year and include leasing commissions paid.

Quarterly_Financial_Informatio1

Quarterly Financial Information (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Selected Quarterly Information	The tables below reflect selected American Assets Trust, Inc. quarterly information for 2014 and 2013 (in thousands, except per shares data):
		Three Months Ended
		December 31,			September 30,			June 30,			March 31,
		2014			2014			2014			2014
	Total revenue	$	66,478		$	67,343		$	62,199		$	63,980
	Operating income	22,526			23,036			17,726			20,381
	Net income	10,046			9,090			5,351			6,658
	Net income attributable to restricted shares	(115		)	(95		)	(94		)	(70		)
	Net income attributable to unitholders in the Operating Partnership	(2,907		)	(2,578		)	(1,544		)	(1,986		)
	Net income attributable to American Assets Trust, Inc. stockholders	$	7,024		$	6,417		$	3,713		$	4,602
	Net income from continuing operations attributable to common stockholders - basic and diluted	$	0.16		$	0.15		$	0.09		$	0.11
	Net income attributable to common stockholders - basic and diluted	$	0.16		$	0.15		$	0.09		$	0.11
		Three Months Ended
		December 31,			September 30,			June 30,			March 31,
		2013			2013			2013			2013
	Total revenue	$	64,645		$	65,318		$	62,914		$	62,180
	Operating income	20,407			21,441			19,373			19,880
	Net income	6,907			6,258			4,564			4,865
	Net income attributable to restricted shares	(139		)	(132		)	(133		)	(132		)
	Net income attributable to unitholders in the Operating Partnership	(2,086		)	(1,903		)	(1,354		)	(1,495		)
	Net income attributable to American Assets Trust, Inc. stockholders	$	4,682		$	4,223		$	3,077		$	3,238
	Net income from continuing operations attributable to common stockholders- basic and diluted	$	0.11		$	0.11		$	0.08		$	0.08
	Net income attributable to common stockholders - basic and diluted	$	0.11		$	0.11		$	0.08		$	0.08

Summary_of_Significant_Account3

Summary of Significant Accounting Policies (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jan. 09, 2014
	Segment
	Room
	Employee
	Property
Summary Of Significant Accounting Policies [Line Items]
Number of employees	113
Number of office, retail, multifamily and mixed-use operating properties	23
Properties held for development	5
Allowance for doubtful accounts	($800,000)	($1,000,000)
Total bad debt expense	200,000	100,000	600,000
Real estate depreciation expense	56,000,000	52,000,000	47,800,000
Short term liquid investments, initial maturity	3 months
Cash balance at banks, federally insured amount		250,000
Cash balance at banks, excess of FDIC insured limit	32,400,000	29,000,000
Restricted cash	10,994,000	9,124,000
Number of operating segments	4
Room in mixed-use segment all-suite hotel	369
Minimum
Summary Of Significant Accounting Policies [Line Items]
Percentage of taxable income required to distribute to qualify as real estate investment trust (REIT)	90.00%
Money Market Funds
Summary Of Significant Accounting Policies [Line Items]
Cash balance at banks, excess of FDIC insured limit	20,000,000	11,000,000
Building And Improvement | Minimum
Summary Of Significant Accounting Policies [Line Items]
Real Estate, estimated useful lives	30 years
Building And Improvement | Maximum
Summary Of Significant Accounting Policies [Line Items]
Real Estate, estimated useful lives	40 years
Furniture And Equipment | Minimum
Summary Of Significant Accounting Policies [Line Items]
Real Estate, estimated useful lives	3 years
Furniture And Equipment | Maximum
Summary Of Significant Accounting Policies [Line Items]
Real Estate, estimated useful lives	15 years
Deferred Rent Receivables
Summary Of Significant Accounting Policies [Line Items]
Allowance for doubtful accounts	-1,200,000	-1,200,000
Other Income
Summary Of Significant Accounting Policies [Line Items]
General excise tax recognized, gross	$3,400,000	$3,500,000	$3,300,000
Term Loan
Summary Of Significant Accounting Policies [Line Items]
Line of credit interest rate (in percents)				3.08%

Summary_of_Significant_Account4

Summary of Significant Accounting Policies Supplemental Disclosures Related to Consolidated Statements of Cash Flows (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Supplemental cash flow information
Total interest costs incurred	$58,455	$60,133	$58,074
Interest capitalized	5,490	2,113	746
Interest expense	52,965	58,020	57,328
Cash paid for interest, net of amounts capitalized (including discontinued operations)	48,032	54,345	55,349
Cash paid for income taxes	404	901	1,239
Supplemental schedule of noncash investing and financing activities
Accounts payable and accrued liabilities for construction in progress	9,908	5,001	4,944
Accrued leasing commissions	763	1,385	-782
Accrued placement fees for senior guaranteed notes payable	750	0	0
Reduction to capital for prepaid equity financing costs	$40	$437	$0

Real_Estate_Details

Real Estate (Details) (USD $)

3 Months Ended

12 Months Ended

0 Months Ended

1 Months Ended

0 Months Ended

1 Months Ended

4 Months Ended

0 Months Ended

1 Months Ended

Dec. 31, 2014

Sep. 30, 2014

Jun. 30, 2014

Mar. 31, 2014

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Dec. 04, 2012

Jan. 24, 2014

Jan. 24, 2012

Aug. 21, 2012

Aug. 21, 2012

Dec. 31, 2012

Dec. 19, 2012

Dec. 19, 2012

sqft

sqft

sqft

Story

Story

Real Estate Properties [Line Items]

Total revenue of specific real estate properties

$13,922,000

$12,300,000

$10,217,000

Operating expenses of specific real estate properties

176,331,000

173,956,000

163,560,000

Operating income (loss)

22,526,000

23,036,000

17,726,000

20,381,000

20,407,000

21,441,000

19,373,000

19,880,000

83,669,000

81,101,000

71,906,000

Net income

10,046,000

9,090,000

5,351,000

6,658,000

6,907,000

6,258,000

4,564,000

4,865,000

31,145,000

22,594,000

51,601,000

160 King Street

Real Estate Properties [Line Items]

Sales price of a specific real estate property

93,800,000

One Beach Street

Real Estate Properties [Line Items]

Date of acquisition

24-Jan-12

Rentable square feet of a specific real estate property

97,000

Number of stories in a real estate property

3

Purchase price of a specific real estate property

36,500,000

Closing costs for a specific real estate property

20,000

Business acquisition, identifiable intangible assets and liabilities, weighted average life

7 years

Total revenue of specific real estate properties

3,900,000

Operating expenses of specific real estate properties

1,000,000

Operating income (loss)

2,900,000

Net income

600,000

City Center

Real Estate Properties [Line Items]

Date of acquisition

21-Aug-12

Rentable square feet of a specific real estate property

497,000

497,000

Number of stories in a real estate property

27

27

Purchase price of a specific real estate property

228,800,000

Closing costs for a specific real estate property

100,000

Business acquisition, identifiable intangible assets and liabilities, weighted average life

5 years 9 months

Approximate additional credits received to purchase price

6,900,000

Total revenue of specific real estate properties

7,000,000

Operating expenses of specific real estate properties

1,600,000

Operating income (loss)

5,400,000

Geary Marketplace

Real Estate Properties [Line Items]

Date of acquisition

19-Dec-12

Rentable square feet of a specific real estate property

35,000

35,000

Purchase price of a specific real estate property

21,000,000

Closing costs for a specific real estate property

$20,000

Business acquisition, identifiable intangible assets and liabilities, weighted average life

19 years 9 months

Percentage of leased real estate property

100.00%

100.00%

Real_Estate_Summary_of_Real_Es

Real Estate Summary of Real Estate Investments (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013
In Thousands, unless otherwise specified
Real Estate Properties [Line Items]
Construction in progress	$195,736		$67,389
Total Real estate, at cost	2,136,824		1,995,417
Accumulated depreciation	-361,424		-318,581
Net real estate	1,775,400		1,676,836
Total Retail
Real Estate Properties [Line Items]
Net real estate	639,456		651,707
Total Office
Real Estate Properties [Line Items]
Net real estate	757,854		750,890
Total Multifamily
Real Estate Properties [Line Items]
Net real estate	182,468		74,612
Total Mixed-Use
Real Estate Properties [Line Items]
Net real estate	195,622		199,627
Real Estate Investment
Real Estate Properties [Line Items]
Land	494,103		493,725
Buildings	1,289,499		1,282,580
Land improvements	53,720		52,793
Tenant improvements	108,310		99,362
Furniture, fixtures, and equipment	12,456		16,568
Construction in progress	178,736	[1]	50,389	[1]
Total Real estate, at cost	2,136,824		1,995,417
Accumulated depreciation	-361,424		-318,581
Net real estate	1,775,400		1,676,836
Real Estate Investment | Total Retail
Real Estate Properties [Line Items]
Land	248,386		248,008
Buildings	500,088		499,091
Land improvements	39,999		39,892
Tenant improvements	50,504		46,649
Furniture, fixtures, and equipment	491		489
Construction in progress	5,327		2,673
Total Real estate, at cost	844,795		836,802
Accumulated depreciation	-205,339		-185,095
Net real estate	639,456		651,707
Real Estate Investment | Total Office
Real Estate Properties [Line Items]
Land	143,575		143,575
Buildings	621,343		618,077
Land improvements	8,273		7,528
Tenant improvements	56,127		51,016
Furniture, fixtures, and equipment	750		517
Construction in progress	31,878		14,189
Total Real estate, at cost	861,946		834,902
Accumulated depreciation	-104,092		-84,012
Net real estate	757,854		750,890
Real Estate Investment | Total Multifamily
Real Estate Properties [Line Items]
Land	25,507		25,507
Buildings	42,270		42,270
Land improvements	3,085		3,010
Tenant improvements	0		0
Furniture, fixtures, and equipment	5,832		5,482
Construction in progress	141,205		32,252
Total Real estate, at cost	217,899		108,521
Accumulated depreciation	-35,431		-33,909
Net real estate	182,468		74,612
Real Estate Investment | Total Mixed-Use
Real Estate Properties [Line Items]
Land	76,635		76,635
Buildings	125,798		123,142
Land improvements	2,363		2,363
Tenant improvements	1,679		1,697
Furniture, fixtures, and equipment	5,383		10,080
Construction in progress	326		1,275
Total Real estate, at cost	212,184		215,192
Accumulated depreciation	-16,562		-15,565
Net real estate	$195,622		$199,627
[1]	Land related to held for development and construction in progress is included in the Held for Development and Construction in Progress classifications on the consolidated balance sheets.

Real_Estate_Allocation_of_Purc

Real Estate Allocation of Purchase Price (Details) (USD $)	Dec. 31, 2012
In Thousands, unless otherwise specified
Business Acquisition [Line Items]
Land	$48,706
Building	213,596
Land improvements	888
Tenant improvements	6,884
Total real estate	270,074
Lease intangibles	17,028
Prepaid expenses and other assets	3,011
Total assets	290,113
Accounts payable and accrued expenses	550
Security deposits payable	815
Lease intangibles	11,239
Other liabilities and deferred credits	519
Total liabilities	13,123
One Beach Street
Business Acquisition [Line Items]
Land	15,332
Building	16,764
Land improvements	30
Tenant improvements	1,223
Total real estate	33,349
Lease intangibles	4,141
Prepaid expenses and other assets	1
Total assets	37,491
Accounts payable and accrued expenses	94
Security deposits payable	75
Lease intangibles	1,382
Other liabilities and deferred credits	22
Total liabilities	1,573
City Center Bellevue
Business Acquisition [Line Items]
Land	25,135
Building	185,653
Land improvements	154
Tenant improvements	5,191
Total real estate	216,133
Lease intangibles	11,870
Prepaid expenses and other assets	2,596
Total assets	230,599
Accounts payable and accrued expenses	456
Security deposits payable	740
Lease intangibles	8,733
Other liabilities and deferred credits	497
Total liabilities	10,426
Geary Marketplace
Business Acquisition [Line Items]
Land	8,239
Building	11,179
Land improvements	704
Tenant improvements	470
Total real estate	20,592
Lease intangibles	1,017
Prepaid expenses and other assets	414
Total assets	22,023
Accounts payable and accrued expenses	0
Security deposits payable	0
Lease intangibles	1,124
Other liabilities and deferred credits	0
Total liabilities	$1,124

Real_Estate_Net_Revenue_and_Ne

Real Estate Net Revenue and Net Income from Property Discontinued Operations (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Real Estate [Abstract]
Net revenue from discontinued operations	$0	$0	$6,734
Results from discontinued operations
Income from discontinued operations	0	0	932
Gain on sale of real estate from discontinued operations	0	0	36,720
Results from discontinued operations	$0	$0	$37,652

Acquired_InPlace_Leases_and_Ab2

Acquired In-Place Leases and Above/Below Market Leases (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of acquired above and below market leases	$2.80	$2.40	($0.20)
Weighted-average amortization period of below market leases	8 years 6 months
Acquired lease, below market renewal options	$17.50
Weighted-average amortization period of acquired leases prior to the commencement of renewal option	10 years 9 months
In-place leases
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted-average amortization period of acquired leases	2 years 5 months
Above Market Leases
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted-average amortization period of acquired leases	1 year 5 months

Acquired_InPlace_Leases_and_Ab3

Acquired In-Place Leases and Above/Below Market Leases Summary of Acquired Lease Intangibles (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Finite-Lived Intangible Assets, Gross [Abstract]
Acquired lease intangible assets	$5,103	$7,399
Net of accumulated amortization of other intangible assets	-1,590	-1,554
Below Market Lease [Abstract]
Below market leases	70,013	76,502
Accumulated accretion	-27,161	-28,592
Acquired lease intangible liabilities, net	42,852	47,910
In-place leases
Finite-Lived Intangible Assets, Gross [Abstract]
Acquired lease intangible assets	53,967	62,813
Net of accumulated amortization of other intangible assets	-35,336	-38,279
Acquired lease intangible assets, net	18,631
Above Market Leases
Finite-Lived Intangible Assets, Gross [Abstract]
Acquired lease intangible assets	22,500	28,279
Net of accumulated amortization of other intangible assets	-17,397	-20,880
Acquired lease intangible assets, net	5,103
Acquired lease intangible assets
Finite-Lived Intangible Assets, Gross [Abstract]
Acquired lease intangible assets, net	$23,734	$31,933

Acquired_InPlace_Leases_and_Ab4

Acquired In-Place Leases and Above/Below Market Leases Increases (Decreases) in Net Income as Result of Amortization of In-Place Leases Above Market Leases and Below Market Leases (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of leases	($3,142)	($6,732)	($10,485)
Amortization of below market leases	5,057	6,440	5,502
In-place leases
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of leases	-5,903	-9,120	-10,248
Above Market Leases
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of leases	($2,296)	($4,052)	($5,739)

Acquired_InPlace_Leases_and_Ab5

Acquired In-Place Leases and Above/Below Market Leases Amortization for Acquired In-Place Leases During Next Five Years and Thereafter Assuming No Early Lease Terminations (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Below Market Lease, Net, Amortization Income, Fiscal Year Maturity [Abstract]
2015	$4,667
2016	4,525
2017	4,169
2018	3,649
2019	3,560
Thereafter	22,282
Acquired lease intangible liabilities, net	42,852	47,910
In-place leases
Acquired Finite-Lived Intangible Assets [Line Items]
2015	4,744
2016	3,954
2017	3,189
2018	1,893
2019	1,452
Thereafter	3,399
Acquired lease intangible assets, net	18,631
Above Market Leases
Acquired Finite-Lived Intangible Assets [Line Items]
2015	1,752
2016	1,263
2017	932
2018	628
2019	318
Thereafter	210
Acquired lease intangible assets, net	$5,103

Marketable_Securities_Details

Marketable Securities (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2012
Investments, Debt and Equity Securities [Abstract]
Realized Loss	$0.70

Fair_Value_of_Financial_Instru2

Fair Value of Financial Instruments (Details) (Fair Value, Inputs, Level 2)	12 Months Ended
	Dec. 31, 2014
Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Interest rate used to estimate fair value of mortgages and notes payable (in percents)	3.62%
Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Interest rate used to estimate fair value of mortgages and notes payable (in percents)	5.73%

Fair_Value_of_Financial_Instru3

Fair Value of Financial Instruments Liabilities Fair Value Measurement on a Recurring Basis (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred compensation liability	$981	$769
Interest rate swap liability	1,448	0
Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred compensation liability	0	0
Interest rate swap liability	0	0
Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred compensation liability	981	769
Interest rate swap liability	1,448	0
Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred compensation liability	0	0
Interest rate swap liability	$0	$0

Fair_Value_of_Financial_Instru4

Fair Value of Financial Instruments Carrying Amount and Fair Value of Financial Instruments (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Secured Debt | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured notes payable	$812,811	$952,174
Secured Debt | Estimate of Fair Value Measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured notes payable	850,475	990,296
Term Loan | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured notes payable	100,000	0
Term Loan | Estimate of Fair Value Measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured notes payable	100,000	0
Line of Credit | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured notes payable	0	93,000
Line of Credit | Estimate of Fair Value Measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured notes payable	0	93,000
Senior Notes, Series A | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured notes payable	150,000	0
Senior Notes, Series A | Estimate of Fair Value Measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured notes payable	$154,560	$0

Other_Assets_Details

Other Assets (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Leasing commissions, net of accumulated amortization of $20,659 and $19,606 respectively	$19,484	$18,071
Acquired above market leases, net	5,103	7,399
Acquired in-place leases, net	18,631	24,534
Lease incentives, net of accumulated amortization of $2,960 and $2,590, respectively	740	1,110
Other intangible assets, net of accumulated amortization of $1,590 and $1,554, respectively	453	655
Debt issuance costs, net of accumulated amortization of $4,147 and $2,985, respectively	5,361	2,632
Prepaid expenses, deposits and other	3,629	3,269
Total other assets	$53,401	$57,670

Other_Assets_Parenthetical_Det

Other Assets (Parenthetical) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Leasing commissions, accumulative amortization	$20,659	$19,606
Lease incentives, accumulated amortization	2,960	2,590
Other intangible assets, accumulated amortization	1,590	1,554
Debt issuance costs, accumulated amortization	$4,147	$2,985

Other_Liabilities_and_Deferred2

Other Liabilities and Deferred Credits (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Other Liabilities Disclosure [Abstract]
Acquired below market leases, net	$42,852	$47,910
Prepaid rent and deferred revenue	7,288	7,506
Derivative Liability	1,448	0
Straight-line rent liability	2,533	1,145
Deferred rent expense	584	829
Deferred compensation	981	769
Deferred tax Liability	219	233
Other liabilities	88	73
Total other liabilities and deferred credits	$55,993	$58,465

Debt_Details

Debt (Details) (USD $)	0 Months Ended					1 Months Ended	0 Months Ended
	Jan. 09, 2014	Sep. 07, 2012	Mar. 29, 2012	Jan. 10, 2012	Mar. 07, 2011	Oct. 31, 2012	Oct. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Oct. 10, 2012	Jan. 19, 2011
Debt Instrument [Line Items]
Unsecured notes payable								$250,000,000	$0
Line of Credit
Debt Instrument [Line Items]
Maximum leverage ratio of revolving credit facility	60.00%
Percent of net proceeds of any additional equity issuances in relation to net proceeds as of Offering	75.00%
Percentage annual distributions cannot exceed funds from operations	95.00%
Maximum unsecured leverage ratio (in percents)	60.00%
Minimum tangible net worth	721,160,000
Maximum recourse indebtedness of total asset value (in percents)	15.00%
Base Rate | Line of Credit
Debt Instrument [Line Items]
Points added to federal funds rate (in percents)	0.50%
Points added to Eurodollar rate (in percents)	1.00%
Prior to December 31, 2015 | Line of Credit
Debt Instrument [Line Items]
Maximum secured leverage ratio on revolving credit facility	45.00%
After December 31, 2015 | Line of Credit
Debt Instrument [Line Items]
Minimum fixed charge coverage ratio on revolving credit facility	1.5
Maximum secured leverage ratio on revolving credit facility	40.00%
Minimum unsecured interest coverage ratio (in percents)	175.00%
American Assets Trust, L.P.
Debt Instrument [Line Items]
Non-recourse mortgage loan						10 years
Original principal amount of non-recourse mortgage loan										111,000,000
Maturity date of loan						1-Nov-22
Interest rate						3.98%
Number of year non-recourse mortgage loan			7 years
Principal of non-recourse mortgage loan			21,900,000
Stated Interest Rate			3.94%
Revolving credit facility borrowing limit, maximum borrowing capacity	350,000,000										250,000,000
Years, maximum maturities of securities					30 years
Year, extension on term of revolving credit facility				1 year
Percent of secured indebtedness of the company's secured total asset value		55.00%
Line of credit facility material acquisition		greater than $100 million
Allowable additional borrowing capacity	250,000,000
Unsecured notes payable								250,000,000	0
American Assets Trust, L.P. | Subject to meeting specified requirements and obtaining additional commitments
Debt Instrument [Line Items]
Revolving credit facility borrowing limit, maximum borrowing capacity											400,000,000
American Assets Trust, L.P. | Revolving Credit Facility
Debt Instrument [Line Items]
Revolving credit facility borrowing limit, maximum borrowing capacity	250,000,000
American Assets Trust, L.P. | Revolving Credit Facility | Line of Credit
Debt Instrument [Line Items]
Extension term (in months)	6 months
Number of extensions available	2
American Assets Trust, L.P. | Term Loan
Debt Instrument [Line Items]
Revolving credit facility borrowing limit, maximum borrowing capacity	100,000,000
Unsecured notes payable	100,000,000
American Assets Trust, L.P. | LIBOR | Line of Credit
Debt Instrument [Line Items]
Variable rate basis	LIBOR
American Assets Trust, L.P. | Base Rate | Line of Credit
Debt Instrument [Line Items]
Variable rate basis	base rate
Prime rate	prime rate
Federal funds rate	federal funds
Eurodollar	Eurodollar
American Assets Trust, L.P. | Minimum | LIBOR | Revolving Credit Facility | Line of Credit
Debt Instrument [Line Items]
Basis spread on variable rate (in percents)	1.35%
American Assets Trust, L.P. | Minimum | LIBOR | Term Loan | Line of Credit
Debt Instrument [Line Items]
Basis spread on variable rate (in percents)	1.30%
American Assets Trust, L.P. | Minimum | Base Rate | Revolving Credit Facility | Line of Credit
Debt Instrument [Line Items]
Basis spread on variable rate (in percents)	0.35%
American Assets Trust, L.P. | Minimum | Base Rate | Term Loan | Line of Credit
Debt Instrument [Line Items]
Basis spread on variable rate (in percents)	0.30%
American Assets Trust, L.P. | Maximum | LIBOR | Revolving Credit Facility | Line of Credit
Debt Instrument [Line Items]
Basis spread on variable rate (in percents)	1.95%
American Assets Trust, L.P. | Maximum | LIBOR | Term Loan | Line of Credit
Debt Instrument [Line Items]
Basis spread on variable rate (in percents)	1.90%
American Assets Trust, L.P. | Maximum | Base Rate | Revolving Credit Facility | Line of Credit
Debt Instrument [Line Items]
Basis spread on variable rate (in percents)	0.95%
American Assets Trust, L.P. | Maximum | Base Rate | Term Loan | Line of Credit
Debt Instrument [Line Items]
Basis spread on variable rate (in percents)	0.90%
American Assets Trust, L.P. | Note Purchase Agreement | Senior Notes
Debt Instrument [Line Items]
Principal of non-recourse mortgage loan							350,000,000
Debt Instrument, Partial Repayment, Minimum Percentage of Principal							5.00%
Debt Instrument, Prepayment, Percentage of Principal Plus a Stated Amount							100.00%
American Assets Trust, L.P. | Note Purchase Agreement | Senior Notes, Series A
Debt Instrument [Line Items]
Principal of non-recourse mortgage loan							150,000,000
Stated Interest Rate							4.04%
Senior Notes								150,000,000
Effective interest rate (percent)							3.88%
American Assets Trust, L.P. | Note Purchase Agreement | Senior Notes, Series B
Debt Instrument [Line Items]
Principal of non-recourse mortgage loan							100,000,000
Stated Interest Rate							4.45%
American Assets Trust, L.P. | Note Purchase Agreement | Senior Notes, Series C
Debt Instrument [Line Items]
Principal of non-recourse mortgage loan							$100,000,000
Stated Interest Rate							4.50%

Debt_Summary_of_Total_Secured_

Debt Summary of Total Secured Notes Payable Outstanding (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	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	1-Nov-14	[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	1-May-15	[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	5-Jul-15	[1],[4]
American Assets Trust, L.P. | Del Monte Center
Debt Instrument [Line Items]
Stated Interest Rate	4.93%	[1],[5]
Stated Maturity Date	8-Jul-15	[1],[5]
American Assets Trust, L.P. | First & Main
Debt Instrument [Line Items]
Stated Interest Rate	3.97%	[1]
Stated Maturity Date	1-Jul-16	[1]
American Assets Trust, L.P. | Imperial Beach Gardens
Debt Instrument [Line Items]
Stated Interest Rate	6.16%	[1]
Stated Maturity Date	1-Sep-16	[1]
American Assets Trust, L.P. | Mariner's Point
Debt Instrument [Line Items]
Stated Interest Rate	6.09%	[1]
Stated Maturity Date	1-Sep-16	[1]
American Assets Trust, L.P. | South Bay Marketplace
Debt Instrument [Line Items]
Stated Interest Rate	5.48%	[1]
Stated Maturity Date	10-Feb-17	[1]
American Assets Trust, L.P. | Waikiki Beach Walk - Retail
Debt Instrument [Line Items]
Stated Interest Rate	5.39%	[1]
Stated Maturity Date	1-Jul-17	[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	1-Aug-17	[6]
American Assets Trust, L.P. | Loma Palisades
Debt Instrument [Line Items]
Stated Interest Rate	6.09%	[1]
Stated Maturity Date	1-Jul-18	[1]
American Assets Trust, L.P. | One Beach Street
Debt Instrument [Line Items]
Stated Interest Rate	3.94%	[1]
Stated Maturity Date	1-Apr-19	[1]
American Assets Trust, L.P. | Torrey Reserve - North Court
Debt Instrument [Line Items]
Stated Interest Rate	7.22%	[6]
Stated Maturity Date	1-Jun-19	[6]
American Assets Trust, L.P. | Torrey Reserve-VCI, VCII, VCIII
Debt Instrument [Line Items]
Stated Interest Rate	6.36%	[6]
Stated Maturity Date	1-Jun-20	[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	1-Jun-20	[6]
American Assets Trust, L.P. | Solana Beach Towne Centre
Debt Instrument [Line Items]
Stated Interest Rate	5.91%	[6]
Stated Maturity Date	1-Jun-20	[6]
American Assets Trust, L.P. | City Center Bellevue
Debt Instrument [Line Items]
Stated Interest Rate	3.98%	[1]
Stated Maturity Date	1-Nov-22	[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 bAnticipated Repayment Dateb 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.

Debt_Summary_of_Total_Unsecure

Debt Summary of Total Unsecured Notes Payable Outstanding (Details) (USD $)	12 Months Ended		0 Months Ended
	Dec. 31, 2014		Aug. 19, 2014	Dec. 31, 2013	Mar. 29, 2012
	Extension_Option
Debt Instrument [Line Items]
Unsecured notes payable	$250,000,000			$0
American Assets Trust, L.P.
Debt Instrument [Line Items]
Unsecured notes payable	250,000,000			0
Stated Interest Rate					3.94%
American Assets Trust, L.P. | Term Loan
Debt Instrument [Line Items]
Unsecured notes payable	100,000,000			0
Stated Maturity Date	9-Jan-19	[1]
Number of extensions available	3
American Assets Trust, L.P. | Senior Guaranteed Notes, Series A
Debt Instrument [Line Items]
Unsecured notes payable	150,000,000			0
Stated Interest Rate	4.04%	[2]
Stated Maturity Date	31-Oct-21
Interest Rate Swap
Debt Instrument [Line Items]
Fixed interest rate on derivative			2.13%
Term of derivative contract			7 years
Interest Rate Swap | American Assets Trust, L.P.
Debt Instrument [Line Items]
Fixed interest rate on derivative	3.08%
Forward Contracts | American Assets Trust, L.P.
Debt Instrument [Line Items]
Term of derivative contract	1 month
Gain on derivatives	$1,600,000
Effective interest rate (percent)	3.88%
[1]	The Operating Partnership has an option to extend the term loan up to three times, with each such extension for a 12-month period. The foregoing extension options are exercisable by the Operating Partnership subject to the satisfaction of certain conditions.
[2]	The company entered into a one-month forward-starting seven-year swap contract on August 19, 2014, which was settled on September 19, 2014 at a gain of approximately $1.6 million (see Note 9). The forward-starting seven-year swap contract was deemed to be a highly effective cash flow hedge, accordingly, the effective interest rate is approximately 3.88% per annum.

Debt_Scheduled_Principal_Payme

Debt Scheduled Principal Payments on Notes Payable (Details) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified
Debt Disclosure [Abstract]
2015	$235,980
2016	113,974
2017	190,139
2018	75,224
2019	142,662
Thereafter	312,004
Notes payable, total	$1,069,983

Derivative_and_Hedging_Details

Derivative and Hedging (Details) (USD $)	0 Months Ended		12 Months Ended
	Aug. 19, 2014	Sep. 19, 2014	Dec. 31, 2014	Dec. 31, 2013
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative liabilities at fair value			$1,448,000	$0
Derivative Liability			1,448,000	0
Interest Rate Swap
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Fixed interest rate on derivative	2.13%
Notional amount	150,000,000
Term of derivative contract	7 years
Cash Flow Hedging | Designated as Hedging Instrument | Interest Rate Swap
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Fixed interest rate on derivative			3.08%
Notional amount			100,000,000
Derivative, Inception Date			9-Jan-14
Derivative, Maturity Date			9-Jan-19
Derivative liabilities at fair value			1,448,000
Gain recognized in other comprehensive income (loss)		$1,600,000

Partners_Capital_of_American_A1

Partners Capital of American Assets Trust, L.P. (Details)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Capital Unit [Line Items]
Noncontrolling common units	17,905,257
Noncontrolling Interest, Ownership Percentage by Parent	70.70%
Percentage of ownership interests classified as noncontrolling	29.30%
Common Stock
Capital Unit [Line Items]
Conversion of operating partnership units (in shares)	11,852	106,326	372,654

Equity_of_American_Assets_Trus2

Equity of American Assets Trust, Inc. (Details) (USD $)	12 Months Ended			0 Months Ended		3 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	6-May-13	Sep. 12, 2014	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2012
				Agent
Equity [Line Items]
Noncontrolling common units	17,905,257
Noncontrolling Interest, Ownership Percentage by Parent	70.70%
Percentage of ownership interests classified as noncontrolling	29.30%
Preferred stock, shares authorized	10,000,000
Preferred stock, par-value	$0.01
Equity incentive award plan, common stock authorized for issuance	4,054,411
Equity incentive award plan, common stock available for future issuance	3,560,872
Noncash compensation expense recognized	$3,700,000	$2,800,000	$2,900,000
Unrecognized compensation expense	5,100,000
Weighted average unvested shares outstanding	430,584	630,130	629,493
Restricted Stock
Equity [Line Items]
Unrecognized compensation expense, weighted-average recognition period (in years)	11 months 19 days
At The Market Equity Program
Equity [Line Items]
Number of Sales Agents				4
Aggregate Offering Price Of Common Share				150,000,000
Common shares issued (in shares)	2,710,067
Weighted average price per share	$33.84
Proceeds from Issuance of Common Stock, Gross	91,700,000
Remaining capacity available for issuance	32,300,000
Commissions | At The Market Equity Program
Equity [Line Items]
Payments of Stock Issuance Costs	-900,000
Other Offering Costs | At The Market Equity Program
Equity [Line Items]
Payments of Stock Issuance Costs	-100,000
ICW Plaza | Board of Directors Chairman | Private Placement
Equity [Line Items]
Common shares issued (in shares)					400,000
Share Price					$33.76
Proceeds from Issuance of Common Stock, Gross					$13,500,000
American Assets Trust, L.P.
Equity [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount						430,584	630,130	629,493

Equity_of_American_Assets_Trus3

Equity of American Assets Trust, Inc. Dividends Declared and Paid on Shares of Common Stock and Noncontrolling Common Units (Details) (USD $)

3 Months Ended

12 Months Ended

Dec. 31, 2014

Sep. 30, 2014

Jun. 30, 2014

Mar. 31, 2014

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Sep. 30, 2012

Jun. 30, 2012

Mar. 31, 2012

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Equity [Abstract]

Dividend Period

Fourth Quarter 2014

Third Quarter 2014

Second Quarter 2014

First Quarter 2014

Fourth Quarter 2013

Third Quarter 2013

Second Quarter 2013

First Quarter 2013

Fourth Quarter 2012

Third Quarter 2012

Second Quarter 2012

First Quarter 2012

Amount per Share/Unit

$0.23

$0.22

$0.22

$0.22

$0.22

$0.21

$0.21

$0.21

$0.21

$0.21

$0.21

$0.21

$0.89

$0.85

$0.84

Dividends Period Covered

October 1, 2014 to December 31, 2014

July 1, 2014 to September 30, 2014

April 1, 2014 to June 30, 2014

January 1, 2014 to March 31, 2014

October 1, 2013 to December 31, 2013

July 1, 2013 to September 30, 2013

April 1, 2013 to June 30, 2013

January 1, 2013 to March 31, 2013

October 1, 2012 to December 31, 2012

July 1, 2012 to September 30, 2012

April 1, 2012 to June 30, 2012

January 1, 2012 to March 31, 2012

Dividend Paid Date

26-Dec-14

26-Sep-14

27-Jun-14

28-Mar-14

27-Dec-13

27-Sep-13

28-Jun-13

29-Mar-13

28-Dec-12

28-Sep-12

29-Jun-12

30-Mar-12

Equity_of_American_Assets_Trus4

Equity of American Assets Trust, Inc. Summary of Income Tax Status of Dividends Per Share Paid (Details) (USD $)	3 Months Ended												12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Equity [Abstract]
Ordinary income													$0.61	$0.83	$0.56
Return of capital													$0.28	$0.02	$0.28
Total	$0.23	$0.22	$0.22	$0.22	$0.22	$0.21	$0.21	$0.21	$0.21	$0.21	$0.21	$0.21	$0.89	$0.85	$0.84
Ordinary income													68.90%	97.60%	66.70%
Return of capital													31.10%	2.40%	33.30%
Total													100.00%	100.00%	100.00%

Equity_of_American_Assets_Trus5

Equity of American Assets Trust, Inc. Restricted Common Stock Issued (Details) (Restricted Stock, USD $)	0 Months Ended
	Dec. 01, 2014	Jun. 17, 2014	Mar. 25, 2014	Jul. 13, 2013	Jul. 10, 2012	Jan. 19, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, Weighted Average Grant Date Fair Value		$34.10		$31.97	$25.05
Granted, Shares	98,765	5,864	112,119	5,004	8,015	2,000
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, Weighted Average Grant Date Fair Value	36.28		28.89			11.91
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, Weighted Average Grant Date Fair Value	36.32		31.25			12.61

Equity_of_American_Assets_Trus6

Equity of American Assets Trust, Inc. Summary of Activity of Restricted Stock Awards (Details) (Restricted Stock Units (RSUs), USD $)	12 Months Ended
	Dec. 31, 2014
Restricted Stock Units (RSUs)
Nonvested, Number of Shares
Nonvested, Beginning, Shares	629,058
Granted, Shares	216,748
Vested, Shares	-351,075
Forfeited, Shares	-1,192
Nonvested, Ending, Shares	493,539
Nonvested, Weighted Average Grant Date Fair Value
Nonvested, Beginning, Weighted Average Grant Date Fair Value	$15.58
Granted, Weighted Average Grant Date Fair Value	$32.96
Vested, Weighted Average Grant Date Fair Value	$17.22
Forfeited, Weighted Average Grant Date Fair Value	$29.83
Nonvested, Ending, Weighted Average Grant Date Fair Value	$22.01

Equity_of_American_Assets_Trus7

Equity of American Assets Trust, Inc. Computation of Basic and Diluted EPS (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
NUMERATOR
Income from continuing operations									$31,145	$22,594	$13,949
Less: Net income attributable to restricted shares	-115	-95	-94	-70	-139	-132	-133	-132	-374	-536	-529
Less: Income from continuing operations attributable to unitholders in the Operating Partnership									-9,015	-6,838	-4,239
Income (loss) from continuing operations attributable to American Assets Trust, Inc. common stockholders-basic									21,756	15,220	9,181
Plus: Results from discontinued operations attributable to American Assets Trust, Inc. common stockholders									0	0	25,757
NET INCOME ATTRIBUTABLE TO AMERICAN ASSETS TRUST, INC. STOCKHOLDERS	7,024	6,417	3,713	4,602	4,682	4,223	3,077	3,238	21,756	15,220	34,938
Income from continuing operations attributable to American Assets Trust, Inc. common stockholdersbbasic									21,756	15,220	9,181
Plus: Income from continuing operations attributable to unitholders in the Operating Partnership									9,015	6,838	4,239
Income (loss) from continuing operations attributable to common stockholders-diluted									30,771	22,058	13,420
Plus: Results from discontinued operations attributable to American Assets Trust, Inc. common stockholders									0	0	25,757
Plus: Results from discontinued operations attributable to unitholders in the Operating Partnership									0	0	11,895
Net income attributable to common stockholders-diluted									$30,771	$22,058	$51,072
DENOMINATOR
Weighted average shares of common stock outstanding-basic (in shares)									42,041,126	39,539,457	38,736,113
Effect of dilutive securities-conversion of Operating Partnership units									17,906,348	17,976,353	18,317,796
Weighted average common shares outstanding - diluted									59,947,474	57,515,810	57,053,909
Earnings (loss) per common share-basic
Continuing operations (in dollars per share)									$0.52	$0.38	$0.24
Discontinued operations (in dollars per share)									$0	$0	$0.66
Basic net income attributable to common stockholders per share (in dollars per share)									$0.52	$0.38	$0.90
Earnings (loss) per common share-diluted
Continuing operations (in dollars per share)									$0.51	$0.38	$0.24
Discontinued operations (in dollars per share)									$0	$0	$0.66
Diluted net income attributable to common stockholders per share (in dollars per share)									$0.51	$0.38	$0.90

Income_Taxes_Details

Income Taxes (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Income Tax Disclosure [Abstract]
Deferred tax Liability	$219	$233

Income_Taxes_Income_Tax_Provis

Income Taxes Income Tax Provision Included in Other Income Expense on Consolidated Statement of Operations (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Statement [Abstract]
Federal	$190	$370	$361
State	284	362	335
Federal	0	-47	118
State	-14	-40	202
Provision for income taxes	$460	$645	$1,016

Commitments_and_Contingencies_2

Commitments and Contingencies (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2012	Dec. 31, 2013
	Property
Commitment And Contingencies [Line Items]
Termination payment	$6.60
Percentage, partner's common units	50.00%
Transfer taxes accrued in connection with the Offering	$6.60
Number of consolidated properties located in Southern California	12
Maximum percentage of total revenue provided by any single tenant	10.00%	10.00%
Total Revenue | Southern California
Commitment And Contingencies [Line Items]
Percentage of total revenue provided by properties	29.90%
Total Revenue | Hawaii
Commitment And Contingencies [Line Items]
Percentage of total revenue provided by properties	20.90%
Rental Income
Commitment And Contingencies [Line Items]
Percentage of total revenue provided by properties	8.70%
Number of tenants that comprise 10.7% of total annualized based rent	3
Maximum | Tenants
Commitment And Contingencies [Line Items]
Percentage of total revenue provided by properties	2.00%
The Land Mark at One Market
Commitment And Contingencies [Line Items]
Number of lease extension options	3
Years, lease extension options length	5 years
Quicksilver
Commitment And Contingencies [Line Items]
Percent annual lease amount increase	3.40%
Waikiki Beach Walk - Retail
Commitment And Contingencies [Line Items]
Property management fee, percent	3.00%
Outrigger Hotels
Commitment And Contingencies [Line Items]
Property management fee, percent	6.00%
Number of calendar months termination fee is based	2 months
Maximum percentage of hotel's fiscal year gross revenues paid for aggregate yearly management fee	3.50%
Previous months of management fees	12 months
Hotel management agreement default penalty factor of previous twelve months of management fees in first 11 years of term	8
Years in hotel management agreement term	11 years
Hotel management agreement default penalty factor of previous twelve months of management fees in twelfth year of term	4
Hotel management agreement default penalty factor of previous twelve months of management fees in thirteenth year of term	3
Hotel management agreement default penalty factor of previous twelve months of management fees in fourteenth year of term	2
Hotel management agreement default penalty factor of previous twelve months of management fees in fifteenth year of term	1
Outrigger Hotels | Future Year Period One
Commitment And Contingencies [Line Items]
Years in hotel management agreement term	15 years
Outrigger Hotels | Future Year Period Two
Commitment And Contingencies [Line Items]
Years in hotel management agreement term	14 years
Outrigger Hotels | Future Year Period Three
Commitment And Contingencies [Line Items]
Years in hotel management agreement term	13 years
Outrigger Hotels | Future Year Period Four
Commitment And Contingencies [Line Items]
Years in hotel management agreement term	12 years
Outrigger Hotels | Maximum
Commitment And Contingencies [Line Items]
Property management fee, percent	3.00%
Wbw Hotel Lessee Llc
Commitment And Contingencies [Line Items]
Years of contract	20 years
Percentage of hotel occupancy gross revenue paid for program fee	4.00%
Wbw Hotel Lessee Llc | Future Time Period Prior to 12-31-2021
Commitment And Contingencies [Line Items]
Percentage of hotel occupancy gross revenue paid for franchise royalty fee	4.00%
Wbw Hotel Lessee Llc | Future Time Period After 12-31-2021
Commitment And Contingencies [Line Items]
Percentage of hotel occupancy gross revenue paid for franchise royalty fee	5.00%
Total Revenues | Retail industry
Commitment And Contingencies [Line Items]
Percentage of total revenue provided by properties	37.00%		36.60%
Total Revenues | Office industry
Commitment And Contingencies [Line Items]
Percentage of total revenue provided by properties	35.60%		35.50%
Base Rent | salesforce.com, inc.
Commitment And Contingencies [Line Items]
Percentage of total revenue provided by properties	8.00%
Alamo Quarry Market and Waikele Center | Total Revenue
Commitment And Contingencies [Line Items]
Percentage of total revenue provided by properties	15.60%		15.80%
Del Monte Center | Ground Water Contamination | Maximum
Commitment And Contingencies [Line Items]
Environmental remediation monitoring period	9 years
Del Monte Center | Ground Water Contamination | Minimum
Commitment And Contingencies [Line Items]
Environmental remediation monitoring period	2 years

Commitments_and_Contingencies_3

Commitments and Contingencies Current Minimum Annual Payments under Leases (Details) (USD $)	Dec. 31, 2014	Jun. 30, 2016	Feb. 28, 2017
Operating Leased Assets [Line Items]
2015	$2,636,000
2016	2,682,000
2017	2,686,000
2018	2,686,000
2019	2,686,000
Thereafter	23,856,000
Total	37,232,000
Scenario, Forecast | The Land Mark at One Market
Operating Leased Assets [Line Items]
Stated monthly lease rate		162,140
Scenario, Forecast | Waikiki Beach Walk
Operating Leased Assets [Line Items]
Stated monthly lease rate			$61,690

Operating_Leases_Details

Operating Leases (Details)	12 Months Ended
	Dec. 31, 2014
	State
	Property
Operating Leased Assets [Line Items]
Number of states where retail, office and mixed-use properties are located	5
Number of leased properties	23
Years, minimum term range of office and retail leases	3 years
Years, maximum term range of office and retail leases	10 years
Months, minimum term of apartment leases	7 months
Months, maximum term of apartment leases	15 months
Retail Or Office
Operating Leased Assets [Line Items]
Number of leased properties	829
Residential Property
Operating Leased Assets [Line Items]
Number of leased properties	794

Operating_Leases_Minimum_Futur

Operating Leases Minimum Future Rentals from Noncancelable Operating Leases (Details) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified
Leases, Operating [Abstract]
2015	$159,988
2016	144,660
2017	128,865
2018	96,844
2019	69,309
Thereafter	193,704
Total	$793,370

Component_of_Rental_Income_and2

Component of Rental Income and Expense (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating Leases, Income Statement, Lease Revenue [Abstract]
Recognition of straight-line rents	$1.90	$2.60	$7.20
Recognition of amortization of above and below market leases	$2.80	$2.40	($0.20)

Component_of_Rental_Income_and3

Component of Rental Income and Expense Components of Rental Income (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Rental Income [Line Items]
Cost reimbursement	$29,052	$27,583	$27,763
Percentage rent	3,107	2,655	2,608
Hotel revenue	33,911	35,137	31,729
Other	1,681	1,688	1,597
Total rental income	246,078	242,757	225,249
Total Retail
Rental Income [Line Items]
Minimum rents	70,573	69,374	67,046
Total Office
Rental Income [Line Items]
Minimum rents	82,018	81,845	71,817
Total Multifamily
Rental Income [Line Items]
Minimum rents	15,732	14,926	13,796
Total Mixed-Use
Rental Income [Line Items]
Minimum rents	$10,004	$9,549	$8,893

Component_of_Rental_Income_and4

Component of Rental Income and Expense Components of Rental Expenses (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating Leases, Income Statement, Lease Revenue [Abstract]
Rental operating	$26,371	$26,028	$24,264
Hotel operating	21,488	22,115	20,905
Repairs and maintenance	10,600	10,514	9,452
Marketing	1,623	1,547	1,266
Rent	2,452	2,442	2,378
Hawaii excise tax	3,981	4,153	3,813
Management fees	1,752	1,809	2,011
Total rental expenses	$68,267	$68,608	$64,089

Other_Income_Expenses_Details

Other Income (Expenses) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Other Income and Expenses [Abstract]
Interest and investment income	$155	$148	$336
Income tax expense	-460	-645	-1,016
Acquisition related expenses	0	0	-152
Other non-operating income	746	10	203
Total other income (expense)	$441	($487)	($629)

Related_Party_Transactions_Det

Related Party Transactions (Details) (USD $)	12 Months Ended			0 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Sep. 12, 2014	Jul. 01, 2014
Related Party Transaction [Line Items]
Total rental income	$246,078,000	$242,757,000	$225,249,000
Investment in WBW CHP LLC, in percentage	47.70%
WBW CHP LLC
Related Party Transaction [Line Items]
Recovered reimbursements of operating expenses of WBW CHP LLC	1,100,000	1,100,000	1,000,000
ICW Plaza | Board of Directors Chairman
Related Party Transaction [Line Items]
Total rental income	2,200,000	2,200,000	2,100,000
Prepaid Insurance					400,000
Private Placement | ICW Plaza | Board of Directors Chairman
Related Party Transaction [Line Items]
Common shares issued (in shares)				400,000
Share Price				$33.76
Proceeds from Issuance of Common Stock, Gross				$13,500,000

Segment_Reporting_Details

Segment Reporting (Details)	12 Months Ended
	Dec. 31, 2014
	Segment
	Room
Segment Reporting [Abstract]
Number of operating segments	4
Room in mixed-use segment all-suite hotel	369

Segment_Reporting_Operating_Ac

Segment Reporting Operating Activity Within Reportable Segments (Detail) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Operating income (loss)	$22,526	$23,036	$17,726	$20,381	$20,407	$21,441	$19,373	$19,880	$83,669	$81,101	$71,906
Gross Profit									168,769	165,071	149,352
Total Retail
Segment Reporting Information [Line Items]
Property revenue									96,140	93,449	91,991
Property expense									-25,451	-23,900	-24,955
Operating income (loss)									70,689	69,549	67,036
Total Office
Segment Reporting Information [Line Items]
Property revenue									92,474	90,527	78,101
Property expense									-27,003	-26,688	-23,780
Operating income (loss)									65,471	63,839	54,321
Total Multifamily
Segment Reporting Information [Line Items]
Property revenue									16,976	16,125	14,852
Property expense									-6,099	-5,917	-5,914
Operating income (loss)									10,877	10,208	8,938
Total Mixed-Use
Segment Reporting Information [Line Items]
Property revenue									54,410	54,956	50,522
Property expense									-32,678	-33,481	-31,465
Operating income (loss)									$21,732	$21,475	$19,057

Segment_Reporting_Reconciliati

Segment Reporting Reconciliation of Segment Profit to Net Income Attributable to Stockholders (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting [Abstract]
Gross Profit									$168,769	$165,071	$149,352
General and administrative									-18,532	-17,195	-15,593
Depreciation and amortization									-66,568	-66,775	-61,853
Interest expense									-52,965	-58,020	-57,328
Other income (expense), net									441	-487	-629
Income from continuing operations									31,145	22,594	13,949
Discontinued operations
Income from discontinued operations									0	0	932
Gain on sale of real estate property									0	0	36,720
Results from discontinued operations									0	0	37,652
Net income	10,046	9,090	5,351	6,658	6,907	6,258	4,564	4,865	31,145	22,594	51,601
Net income attributable to restricted shares	-115	-95	-94	-70	-139	-132	-133	-132	-374	-536	-529
Net income attributable to unitholders in the Operating Partnership	-2,907	-2,578	-1,544	-1,986	-2,086	-1,903	-1,354	-1,495	-9,015	-6,838	-16,134
Net income attributable to American Assets Trust, Inc. stockholders	$7,024	$6,417	$3,713	$4,602	$4,682	$4,223	$3,077	$3,238	$21,756	$15,220	$34,938

Segment_Reporting_Net_Real_Est

Segment Reporting Net Real Estate and Secured Note Payable Balances for Each Segment (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Segment Reporting Information [Line Items]
Net Real Estate	$1,775,400		$1,676,836
Secured Notes Payable	819,983	[1]	962,259	[1]
Capital Expenditures and Leasing Commissions	149,772	[2]	58,707	[2]
Total Retail
Segment Reporting Information [Line Items]
Net Real Estate	639,456		651,707
Secured Notes Payable	161,975		303,249
Capital Expenditures and Leasing Commissions	8,671		4,849
Total Office
Segment Reporting Information [Line Items]
Net Real Estate	757,854		750,890
Secured Notes Payable	426,254		427,256
Capital Expenditures and Leasing Commissions	34,577		27,275
Total Multifamily
Segment Reporting Information [Line Items]
Net Real Estate	182,468		74,612
Secured Notes Payable	101,444		101,444
Capital Expenditures and Leasing Commissions	101,392		24,641
Total Mixed-Use
Segment Reporting Information [Line Items]
Net Real Estate	195,622		199,627
Secured Notes Payable	130,310		130,310
Capital Expenditures and Leasing Commissions	$5,132		$1,942
[1]	Excludes unamortized fair market value adjustment of $7.2 million and $10.1 million as of DecemberB 31, 2014 and 2013, respectively.
[2]	Capital expenditures represent cash paid for capital expenditures during the year and include leasing commissions paid.

Quarterly_Financial_Informatio2

Quarterly Financial Information (Unaudited) Selected Quarterly Information (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Quarterly Financial Information [Line Items]
Total revenue	$66,478	$67,343	$62,199	$63,980	$64,645	$65,318	$62,914	$62,180	$260,000	$255,057	$235,466
Operating income (loss)	22,526	23,036	17,726	20,381	20,407	21,441	19,373	19,880	83,669	81,101	71,906
Income (loss) from continuing operations									31,145	22,594	13,949
Results from discontinued operations									0	0	37,652
Net income	10,046	9,090	5,351	6,658	6,907	6,258	4,564	4,865	31,145	22,594	51,601
Net income attributable to restricted shares	-115	-95	-94	-70	-139	-132	-133	-132	-374	-536	-529
Net income from continuing operations attributable to common stockholders-basic and diluted	$0.16	$0.15	$0.09	$0.11	$0.11	$0.11	$0.08	$0.08
Net income attributable to common stockholders-basic and diluted	$0.16	$0.15	$0.09	$0.11	$0.11	$0.11	$0.08	$0.08
American Assets Trust, L.P.
Quarterly Financial Information [Line Items]
Total revenue	66,478	67,343	62,199	63,980	64,645	65,318	62,914	62,180	260,000	255,057	235,466
Operating income (loss)	22,526	23,036	17,726	20,381	20,407	21,441	19,373	19,880	83,669	81,101	71,906
Income (loss) from continuing operations									31,145	22,594	13,949
Results from discontinued operations									0	0	37,652
Net income	10,046	9,090	5,351	6,658	6,907	6,258	4,564	4,865	31,145	22,594	51,601
Net income attributable to restricted shares	115	95	94	70	139	132	133	132	-374	-536	-529
Net income from continuing operations attributable to common stockholders-basic and diluted	$0.16	$0.15	$0.09	$0.11	$0.11	$0.11	$0.08	$0.08
Net income attributable to common stockholders-basic and diluted	$0.16	$0.15	$0.09	$0.11	$0.11	$0.11	$0.08	$0.08
Net Income (Loss) Allocated to Limited Partners	-2,907	-2,578	-1,544	-1,986	-2,086	-1,903	-1,354	-1,495
Net Income (Loss) Allocated to General Partners	$7,024	$6,417	$3,713	$4,602	$4,682	$4,223	$3,077	$3,238

Subsequent_Events_Details

Subsequent Events (Details) (Note Purchase Agreement, Senior Notes, Series B, Subsequent Event, USD $)	Feb. 20, 2015
Note Purchase Agreement | Senior Notes, Series B | Subsequent Event
Subsequent Event [Line Items]
Debt Instrument, Face Amount	$100,000,000

SCHEDULE_IIIConsolidated_Real_1

SCHEDULE III-Consolidated Real Estate and Accumulated Depreciation (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Real Estate and Accumulated Depreciation [Line Items]
Encumbrance as of December 31, 2013	$819,983,000
Initial Cost, Land	457,017,000
Initial Cost, Building and Improvements	1,191,446,000
Cost Capitalized Subsequent to Acquisition	488,361,000
Gross Carrying Amount, Land	494,103,000
Gross Carrying Amount, Building and Improvements	1,642,721,000
Accumulated Depreciation and Amortization	-361,424,000	-318,581,000	-270,494,000	-234,595,000
The Aggregate tax basis for Federal tax purposes	1,400,000,000
Alamo Quarry Market
Real Estate and Accumulated Depreciation [Line Items]
Encumbrance as of December 31, 2013	0
Initial Cost, Land	26,396,000
Initial Cost, Building and Improvements	109,294,000
Cost Capitalized Subsequent to Acquisition	13,181,000
Gross Carrying Amount, Land	26,816,000
Gross Carrying Amount, Building and Improvements	122,055,000
Accumulated Depreciation and Amortization	-41,786,000
Year Built/ Renovated	1997/1999
Date Acquired	9-Dec-03
Life on which depreciation in latest income statements is computed	35 years
Carmel Country Plaza
Real Estate and Accumulated Depreciation [Line Items]
Encumbrance as of December 31, 2013	0
Initial Cost, Land	4,200,000
Initial Cost, Building and Improvements	0
Cost Capitalized Subsequent to Acquisition	11,639,000
Gross Carrying Amount, Land	4,200,000
Gross Carrying Amount, Building and Improvements	11,639,000
Accumulated Depreciation and Amortization	-6,871,000
Year Built/ Renovated	1991
Date Acquired	10-Jan-89
Life on which depreciation in latest income statements is computed	35 years
Carmel Mountain Plaza
Real Estate and Accumulated Depreciation [Line Items]
Encumbrance as of December 31, 2013	0
Initial Cost, Land	22,477,000
Initial Cost, Building and Improvements	65,217,000
Cost Capitalized Subsequent to Acquisition	23,719,000
Gross Carrying Amount, Land	31,035,000
Gross Carrying Amount, Building and Improvements	80,378,000
Accumulated Depreciation and Amortization	-28,807,000
Year Built/ Renovated	1994/2014
Date Acquired	28-Mar-03
Life on which depreciation in latest income statements is computed	35 years
Del Monte Center
Real Estate and Accumulated Depreciation [Line Items]
Encumbrance as of December 31, 2013	82,300,000
Initial Cost, Land	27,412,000
Initial Cost, Building and Improvements	87,570,000
Cost Capitalized Subsequent to Acquisition	22,300,000
Gross Carrying Amount, Land	27,117,000
Gross Carrying Amount, Building and Improvements	110,165,000
Accumulated Depreciation and Amortization	-45,368,000
Year Built/ Renovated	1967/1984/2006
Date Acquired	8-Apr-04
Life on which depreciation in latest income statements is computed	35 years
Geary Marketplace
Real Estate and Accumulated Depreciation [Line Items]
Encumbrance as of December 31, 2013	0
Initial Cost, Land	8,239,000
Initial Cost, Building and Improvements	12,353,000
Cost Capitalized Subsequent to Acquisition	129,000
Gross Carrying Amount, Land	8,238,000
Gross Carrying Amount, Building and Improvements	12,483,000
Accumulated Depreciation and Amortization	-818,000
Year Built/ Renovated	2012
Date Acquired	19-Dec-12
Life on which depreciation in latest income statements is computed	35 years
Lomas Santa Fe Plaza
Real Estate and Accumulated Depreciation [Line Items]
Encumbrance as of December 31, 2013	0
Initial Cost, Land	8,600,000
Initial Cost, Building and Improvements	11,282,000
Cost Capitalized Subsequent to Acquisition	11,269,000
Gross Carrying Amount, Land	8,620,000
Gross Carrying Amount, Building and Improvements	22,531,000
Accumulated Depreciation and Amortization	-13,225,000
Year Built/ Renovated	1972/1997
Date Acquired	12-Jun-95
Life on which depreciation in latest income statements is computed	35 years
Rancho Carmel Plaza
Real Estate and Accumulated Depreciation [Line Items]
Encumbrance as of December 31, 2013	0
Initial Cost, Land	3,450,000
Initial Cost, Building and Improvements	0
Cost Capitalized Subsequent to Acquisition	3,914,000
Gross Carrying Amount, Land	3,487,000
Gross Carrying Amount, Building and Improvements	3,877,000
Accumulated Depreciation and Amortization	-2,243,000
Year Built/ Renovated	1993
Date Acquired	30-Apr-90
Life on which depreciation in latest income statements is computed	35 years
The Shops at Kalakaua
Real Estate and Accumulated Depreciation [Line Items]
Encumbrance as of December 31, 2013	19,000,000
Initial Cost, Land	13,993,000
Initial Cost, Building and Improvements	10,919,000
Cost Capitalized Subsequent to Acquisition	100,000
Gross Carrying Amount, Land	14,006,000
Gross Carrying Amount, Building and Improvements	11,006,000
Accumulated Depreciation and Amortization	-3,364,000
Year Built/ Renovated	1971/2006
Date Acquired	31-Mar-05
Life on which depreciation in latest income statements is computed	35 years
Solana Beach Towne Centre
Real Estate and Accumulated Depreciation [Line Items]
Encumbrance as of December 31, 2013	37,675,000
Initial Cost, Land	40,980,000
Initial Cost, Building and Improvements	38,842,000
Cost Capitalized Subsequent to Acquisition	1,854,000
Gross Carrying Amount, Land	40,980,000
Gross Carrying Amount, Building and Improvements	40,696,000
Accumulated Depreciation and Amortization	-5,419,000
Year Built/ Renovated	1973/2000/2004
Date Acquired	19-Jan-11
Life on which depreciation in latest income statements is computed	35 years
South Bay Marketplace
Real Estate and Accumulated Depreciation [Line Items]
Encumbrance as of December 31, 2013	23,000,000
Initial Cost, Land	4,401,000
Initial Cost, Building and Improvements	0
Cost Capitalized Subsequent to Acquisition	10,751,000
Gross Carrying Amount, Land	4,401,000
Gross Carrying Amount, Building and Improvements	10,751,000
Accumulated Depreciation and Amortization	-6,112,000
Year Built/ Renovated	1997
Date Acquired	16-Sep-95
Life on which depreciation in latest income statements is computed	35 years
Waikele Center
Real Estate and Accumulated Depreciation [Line Items]
Encumbrance as of December 31, 2013	0
Initial Cost, Land	55,593,000
Initial Cost, Building and Improvements	126,858,000
Cost Capitalized Subsequent to Acquisition	59,021,000
Gross Carrying Amount, Land	70,643,000
Gross Carrying Amount, Building and Improvements	170,829,000
Accumulated Depreciation and Amortization	-51,137,000
Year Built/ Renovated	1993/2008
Date Acquired	16-Sep-04
Life on which depreciation in latest income statements is computed	35 years
City Center Bellevue
Real Estate and Accumulated Depreciation [Line Items]
Encumbrance as of December 31, 2013	111,000,000
Initial Cost, Land	25,135,000
Initial Cost, Building and Improvements	190,998,000
Cost Capitalized Subsequent to Acquisition	10,674,000
Gross Carrying Amount, Land	25,135,000
Gross Carrying Amount, Building and Improvements	201,672,000
Accumulated Depreciation and Amortization	-15,254,000
Year Built/ Renovated	1987
Date Acquired	21-Aug-12
Life on which depreciation in latest income statements is computed	40 years
First & Main
Real Estate and Accumulated Depreciation [Line Items]
Encumbrance as of December 31, 2013	84,500,000
Initial Cost, Land	14,697,000
Initial Cost, Building and Improvements	109,739,000
Cost Capitalized Subsequent to Acquisition	3,095,000
Gross Carrying Amount, Land	14,697,000
Gross Carrying Amount, Building and Improvements	112,834,000
Accumulated Depreciation and Amortization	-13,796,000
Year Built/ Renovated	2010
Date Acquired	11-Mar-11
Life on which depreciation in latest income statements is computed	40 years
The Land Mark at One Market
Real Estate and Accumulated Depreciation [Line Items]
Encumbrance as of December 31, 2013	133,000,000
Initial Cost, Land	34,575,000
Initial Cost, Building and Improvements	141,196,000
Cost Capitalized Subsequent to Acquisition	7,994,000
Gross Carrying Amount, Land	34,575,000
Gross Carrying Amount, Building and Improvements	149,190,000
Accumulated Depreciation and Amortization	-20,780,000
Year Built/ Renovated	1917/2000
Date Acquired	30-Jun-10
Life on which depreciation in latest income statements is computed	40 years
Lloyd District Portfolio
Real Estate and Accumulated Depreciation [Line Items]
Encumbrance as of December 31, 2013	0
Initial Cost, Land	18,660,000
Initial Cost, Building and Improvements	61,401,000
Cost Capitalized Subsequent to Acquisition	151,933,000
Gross Carrying Amount, Land	18,875,000
Gross Carrying Amount, Building and Improvements	213,119,000
Accumulated Depreciation and Amortization	-9,597,000
Year Built/ Renovated	1940-2011/present
Date Acquired	1-Jul-11
Life on which depreciation in latest income statements is computed	40 years
One Beach Street
Real Estate and Accumulated Depreciation [Line Items]
Encumbrance as of December 31, 2013	21,900,000
Initial Cost, Land	15,332,000
Initial Cost, Building and Improvements	18,017,000
Cost Capitalized Subsequent to Acquisition	2,367,000
Gross Carrying Amount, Land	15,332,000
Gross Carrying Amount, Building and Improvements	20,384,000
Accumulated Depreciation and Amortization	-1,971,000
Year Built/ Renovated	1924/1972/1987/1992
Date Acquired	24-Jan-12
Life on which depreciation in latest income statements is computed	40 years
Solana Beach Corporate Centre I-II
Real Estate and Accumulated Depreciation [Line Items]
Encumbrance as of December 31, 2013	11,302,000
Initial Cost, Land	7,111,000
Initial Cost, Building and Improvements	17,100,000
Cost Capitalized Subsequent to Acquisition	2,795,000
Gross Carrying Amount, Land	7,111,000
Gross Carrying Amount, Building and Improvements	19,895,000
Accumulated Depreciation and Amortization	-2,480,000
Year Built/ Renovated	1982/2005
Date Acquired	19-Jan-11
Life on which depreciation in latest income statements is computed	40 years
Solana Beach Corporate Centre III-IV
Real Estate and Accumulated Depreciation [Line Items]
Encumbrance as of December 31, 2013	36,376,000
Initial Cost, Land	7,298,000
Initial Cost, Building and Improvements	27,887,000
Cost Capitalized Subsequent to Acquisition	1,231,000
Gross Carrying Amount, Land	7,298,000
Gross Carrying Amount, Building and Improvements	29,118,000
Accumulated Depreciation and Amortization	-4,003,000
Year Built/ Renovated	1982/2005
Date Acquired	19-Jan-11
Life on which depreciation in latest income statements is computed	40 years
Solana Beach Corporate Centre Land
Real Estate and Accumulated Depreciation [Line Items]
Encumbrance as of December 31, 2013	0
Initial Cost, Land	487,000
Initial Cost, Building and Improvements	0
Cost Capitalized Subsequent to Acquisition	60,000
Gross Carrying Amount, Land	547,000
Gross Carrying Amount, Building and Improvements	0
Accumulated Depreciation and Amortization	0
Year Built/ Renovated	N/A
Date Acquired	19-Jan-11
ICW Plaza
Real Estate and Accumulated Depreciation [Line Items]
Encumbrance as of December 31, 2013	0
Initial Cost, Land	4,095,000
Initial Cost, Building and Improvements	0
Cost Capitalized Subsequent to Acquisition	39,064,000
Gross Carrying Amount, Land	5,408,000
Gross Carrying Amount, Building and Improvements	37,751,000
Accumulated Depreciation and Amortization	-10,918,000
Year Built/ Renovated	1996-1997/2014
Date Acquired	6-Jun-89
Life on which depreciation in latest income statements is computed	40 years
Pacific North Court
Real Estate and Accumulated Depreciation [Line Items]
Encumbrance as of December 31, 2013	21,075,000
Initial Cost, Land	3,263,000
Initial Cost, Building and Improvements	0
Cost Capitalized Subsequent to Acquisition	20,885,000
Gross Carrying Amount, Land	4,309,000
Gross Carrying Amount, Building and Improvements	19,839,000
Accumulated Depreciation and Amortization	-9,160,000
Year Built/ Renovated	1997-1998
Date Acquired	6-Jun-89
Life on which depreciation in latest income statements is computed	40 years
Pacific South Court
Real Estate and Accumulated Depreciation [Line Items]
Encumbrance as of December 31, 2013	0
Initial Cost, Land	3,285,000
Initial Cost, Building and Improvements	0
Cost Capitalized Subsequent to Acquisition	22,021,000
Gross Carrying Amount, Land	4,226,000
Gross Carrying Amount, Building and Improvements	21,080,000
Accumulated Depreciation and Amortization	-10,003,000
Year Built/ Renovated	1996-1997
Date Acquired	6-Jun-89
Life on which depreciation in latest income statements is computed	40 years
Pacific VC
Real Estate and Accumulated Depreciation [Line Items]
Encumbrance as of December 31, 2013	7,101,000
Initial Cost, Land	1,413,000
Initial Cost, Building and Improvements	0
Cost Capitalized Subsequent to Acquisition	8,180,000
Gross Carrying Amount, Land	2,148,000
Gross Carrying Amount, Building and Improvements	7,445,000
Accumulated Depreciation and Amortization	-4,099,000
Year Built/ Renovated	1998/2000
Date Acquired	6-Jun-89
Life on which depreciation in latest income statements is computed	40 years
Pacific Torrey Daycare
Real Estate and Accumulated Depreciation [Line Items]
Encumbrance as of December 31, 2013	0
Initial Cost, Land	715,000
Initial Cost, Building and Improvements	0
Cost Capitalized Subsequent to Acquisition	1,671,000
Gross Carrying Amount, Land	911,000
Gross Carrying Amount, Building and Improvements	1,475,000
Accumulated Depreciation and Amortization	-769,000
Year Built/ Renovated	1996-1997
Date Acquired	6-Jun-89
Life on which depreciation in latest income statements is computed	40 years
Torrey Reserve Building 6
Real Estate and Accumulated Depreciation [Line Items]
Encumbrance as of December 31, 2013	0
Initial Cost, Land	0
Initial Cost, Building and Improvements	0
Cost Capitalized Subsequent to Acquisition	7,907,000
Gross Carrying Amount, Land	682,000
Gross Carrying Amount, Building and Improvements	7,225,000
Accumulated Depreciation and Amortization	-297,000
Year Built/ Renovated	2013
Date Acquired	6-Jun-89
Life on which depreciation in latest income statements is computed	40 years
Torrey Reserve Land
Real Estate and Accumulated Depreciation [Line Items]
Encumbrance as of December 31, 2013	0
Initial Cost, Land	229,000
Initial Cost, Building and Improvements	0
Cost Capitalized Subsequent to Acquisition	19,912,000
Gross Carrying Amount, Land	3,205,000
Gross Carrying Amount, Building and Improvements	16,936,000
Accumulated Depreciation and Amortization	0
Year Built/ Renovated	2014-present
Date Acquired	6-Jun-89
Imperial Beach Gardens
Real Estate and Accumulated Depreciation [Line Items]
Encumbrance as of December 31, 2013	20,000,000
Initial Cost, Land	1,281,000
Initial Cost, Building and Improvements	4,820,000
Cost Capitalized Subsequent to Acquisition	4,180,000
Gross Carrying Amount, Land	1,281,000
Gross Carrying Amount, Building and Improvements	9,000,000
Accumulated Depreciation and Amortization	-7,512,000
Year Built/ Renovated	1959/2008-present
Date Acquired	31-Jul-85
Life on which depreciation in latest income statements is computed	30 years
Loma Palisades
Real Estate and Accumulated Depreciation [Line Items]
Encumbrance as of December 31, 2013	73,744,000
Initial Cost, Land	14,000,000
Initial Cost, Building and Improvements	16,570,000
Cost Capitalized Subsequent to Acquisition	18,304,000
Gross Carrying Amount, Land	14,051,000
Gross Carrying Amount, Building and Improvements	34,823,000
Accumulated Depreciation and Amortization	-24,049,000
Year Built/ Renovated	1958/2001-2008
Date Acquired	20-Jul-90
Life on which depreciation in latest income statements is computed	30 years
Mariner's Point
Real Estate and Accumulated Depreciation [Line Items]
Encumbrance as of December 31, 2013	7,700,000
Initial Cost, Land	2,744,000
Initial Cost, Building and Improvements	4,540,000
Cost Capitalized Subsequent to Acquisition	1,187,000
Gross Carrying Amount, Land	2,744,000
Gross Carrying Amount, Building and Improvements	5,727,000
Accumulated Depreciation and Amortization	-2,479,000
Year Built/ Renovated	1986
Date Acquired	9-May-01
Life on which depreciation in latest income statements is computed	30 years
Santa Fe Park Rv Resort
Real Estate and Accumulated Depreciation [Line Items]
Encumbrance as of December 31, 2013	0
Initial Cost, Land	401,000
Initial Cost, Building and Improvements	928,000
Cost Capitalized Subsequent to Acquisition	818,000
Gross Carrying Amount, Land	401,000
Gross Carrying Amount, Building and Improvements	1,746,000
Accumulated Depreciation and Amortization	-1,391,000
Year Built/ Renovated	1971/2007-2008
Date Acquired	1-Jun-79
Life on which depreciation in latest income statements is computed	30 years
Waikiki Beach Walk - Retail
Real Estate and Accumulated Depreciation [Line Items]
Encumbrance as of December 31, 2013	130,310,000
Initial Cost, Land	45,995,000
Initial Cost, Building and Improvements	74,943,000
Cost Capitalized Subsequent to Acquisition	42,000
Gross Carrying Amount, Land	45,995,000
Gross Carrying Amount, Building and Improvements	74,985,000
Accumulated Depreciation and Amortization	-9,315,000
Year Built/ Renovated	2006
Date Acquired	19-Jan-11
Life on which depreciation in latest income statements is computed	35 years
Waikiki Beach Walk Hotel
Real Estate and Accumulated Depreciation [Line Items]
Encumbrance as of December 31, 2013	0
Initial Cost, Land	30,640,000
Initial Cost, Building and Improvements	60,029,000
Cost Capitalized Subsequent to Acquisition	535,000
Gross Carrying Amount, Land	30,640,000
Gross Carrying Amount, Building and Improvements	60,564,000
Accumulated Depreciation and Amortization	-7,248,000
Year Built/ Renovated	2008/2014
Date Acquired	19-Jan-11
Life on which depreciation in latest income statements is computed	35 years
Solana Beach Highway 101 Land
Real Estate and Accumulated Depreciation [Line Items]
Encumbrance as of December 31, 2013	0
Initial Cost, Land	7,847,000
Initial Cost, Building and Improvements	202,000
Cost Capitalized Subsequent to Acquisition	795,000
Gross Carrying Amount, Land	8,844,000
Gross Carrying Amount, Building and Improvements	0
Accumulated Depreciation and Amortization	-189,000
Year Built/ Renovated	N/A
Date Acquired	20-Sep-11
Sorrento Valley Holdings Land
Real Estate and Accumulated Depreciation [Line Items]
Encumbrance as of December 31, 2013	0
Initial Cost, Land	2,073,000
Initial Cost, Building and Improvements	741,000
Cost Capitalized Subsequent to Acquisition	4,834,000
Gross Carrying Amount, Land	6,145,000
Gross Carrying Amount, Building and Improvements	1,503,000
Accumulated Depreciation and Amortization	($964,000)
Year Built/ Renovated	N/A
Date Acquired	9-May-97

SCHEDULE_IIIConsolidated_Real_2

SCHEDULE III-Consolidated Real Estate and Accumulated Depreciation Rollforward (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Real estate assets
Balance, beginning of period	$1,995,417		$1,938,676		$1,687,276
Property acquisitions	0		0		270,082
Improvements	154,594	[1]	60,677	[1]	41,303	[1]
Cost of Real Estate Sold	0		0		-57,188
Other	-13,187	[1],[2]	-3,936	[1],[2]	-2,797	[1],[2]
Balance, end of period	2,136,824		1,995,417		1,938,676
Accumulated depreciation
Balance, beginning of period	318,581		270,494		234,595
Additions-depreciation	55,159	[1]	51,949	[1]	47,792	[1]
Cost of Real Estate Sold	0		0		-9,216
Other	-12,316	[1],[2]	-3,862	[1],[2]	-2,677	[1],[2]
Balance, end of period	$361,424		$318,581		$270,494
[1]	Includes discontinued operations for 160 King Street, which was sold on December 4, 2012.
[2]	Other deductions for the years ended DecemberB 31, 2014, 2013 and 2012 represent the write-off of fully depreciated assets.

Uncategorized_Items

Uncategorized Items
[us-gaap_SharesOutstanding]	39,283,796