Associated Estates Realty 10-Q 1 May 15 2015 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2015	Apr. 27, 2015
Document and Entity Information [Abstract]
Entity Registrant Name	ASSOCIATED ESTATES REALTY CORP
Entity Central Index Key	911635
Current Fiscal Year End Date	-19
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	31-Mar-15
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Amendment Flag	FALSE
Entity Common Stock, Shares Outstanding		57,889,028
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes

Consolidated_Balance_Sheets_Un

Consolidated Balance Sheets (Unaudited) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Real estate assets
Land	$282,431	$261,777
Buildings and improvements	1,422,288	1,346,870
Furniture and fixtures	43,470	41,609
Construction in progress	75,826	73,581
Gross real estate	1,824,015	1,723,837
Less: Accumulated depreciation	-404,491	-397,210
Real estate held for sale, net of accumulated depreciation of $7,444	6,209	0
Net real estate owned	1,425,733	1,326,627
Investment in unconsolidated entities	55,084	54,800
Total net real estate	1,480,817	1,381,427
Cash and cash equivalents	6,952	4,692
Restricted cash	4,148	46,361
Accounts receivable, net
Rents	1,030	1,093
Other	3,775	2,977
Other assets, net	29,793	29,147
Total assets	1,526,515	1,465,697
LIABILITIES AND EQUITY
Mortgage notes payable	282,587	272,613
Unsecured notes	250,000	250,000
Unsecured revolving credit facility	144,000	76,500
Unsecured term loan	150,000	150,000
Total debt	826,587	749,113
Accounts payable and other liabilities	40,747	47,070
Dividends payable	13,053	12,886
Resident security deposits	4,010	3,860
Accrued interest	4,852	5,192
Total liabilities	889,249	818,121
Equity
Common shares, without par value; $.10 stated value; 91,000,000 authorized; 57,929,535 issued and 57,885,841 outstanding at March 31, 2015 and 57,708,675 issued and 57,649,609 outstanding at December 31, 2014, respectively	5,793	5,771
Paid-in capital	759,526	758,079
Accumulated distributions in excess of accumulated net income	-126,084	-114,551
Accumulated other comprehensive loss	-1,229	-1,093
Less: Treasury shares, at cost, 43,694 and 56,066 shares at March 31, 2015 and December 31, 2014, respectively	-1,090	-980
Total shareholders' equity attributable to AERC	636,916	647,226
Noncontrolling interest	350	350
Total equity	637,266	647,576
Total liabilities and equity	$1,526,515	$1,465,697

Consolidated_Balance_Sheets_Un1

Consolidated Balance Sheets (Unaudited) (Parenthetical) (Parentheticals) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Accumulated depreciation	$404,491,000	$397,210,000
Stockholders' Equity:
Common stock, par value
Common stock, stated value	$0.10	$0.10
Common stock, shares authorized	91,000,000	91,000,000
Common stock, shares issued	57,929,535	57,708,675
Common stock, shares outstanding	57,885,841	57,649,609
Treasury Stock, shares	43,694	59,066
Clinton place [Domain]
Accumulated depreciation	$7,444	$0

Consolidated_Statement_of_Oper

Consolidated Statement of Operations and Comprehensive Income (Unaudited) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Revenue
Property revenue	$47,317	$49,150
Office revenue	611	478
Property management and construction services revenue	315	87
Total revenue	48,243	49,715
Expenses
Property operating and maintenance	18,910	19,368
Depreciation and amortization	15,935	16,295
General and administrative	6,520	5,319
Development costs	199	330
Construction services	203	57
Costs associated with acquisitions	62	86
Total expenses	41,829	41,455
Operating income	6,414	8,260
Interest expense	-6,114	-6,953
Gain on change in control	444	0
Gain on disposition of properties	0	40,966
Net income	744	42,273
Allocation to participating securities	0	157
Net income applicable to common shares	744	42,116
Earnings per common share - basic:
Net income applicable to common shares - basic	$0.01	$0.73
Earnings per common share - diluted:
Net income applicable to common shares - diluted	$0.01	$0.73
Comprehensive income:
Net income	744	42,273
Change in fair value and reclassification of hedge instruments	-136	-63
Total comprehensive income	$608	$42,210
Dividends declared per common share	$0.21	$0.19
Weighted average number of common shares outstanding - basic	57,612	57,362
Weighted average number of common shares outstanding - diluted	58,225	57,833

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (Unaudited) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Cash flow from operating activities:
Net income	$744	$42,273
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	-15,935	-16,295
Gain on change in control	-444	0
Gain on disposition of properties	0	-40,966
Amortization of deferred financing costs and other	252	277
Share-based compensation expense	1,301	1,333
Net change in assets and liabilities:
Accounts receivable	27	575
Accounts payable and accrued expenses	-2,604	-5,709
Other operating assets and liabilities	-897	-1,510
Total adjustments	13,570	-29,705
Net cash flow provided by operating activities	14,314	12,568
Cash flow from investing activities:
Recurring fixed asset additions	-2,832	-1,914
Revenue enhancing/non-recurring fixed asset additions	-1,611	-325
Acquisition fixed asset additions	-82,170	-654
Development fixed asset additions	-15,287	-13,617
Acquisition of unconsolidated entity	-8,316	0
Net proceeds from disposition of operating properties	0	58,086
Contributions to joint venture	-8,901	-588
Deposits on potential future acquisitions	-70	0
Cash proceeds from sale of equity interest in development property	0	24,075
Escrow deposits related to property sales	43,295	0
Costs paid on behalf of joint venture	0	-2,734
Other investing activity	-634	-378
Net cash flow (used for) provided by investing activities	-76,526	61,951
Cash flow from financing activities:
Principal amortization payments on mortgage notes payable	-578	-511
Principal repayments of mortgage notes payable	0	-20,038
Payment of debt procurement costs	-34	-130
Proceeds from secured construction loans	10,741	10,351
Revolving credit facility borrowings	117,000	110,500
Revolving credit facility repayments	-49,500	-155,000
Common share dividends paid	-11,992	-11,747
Purchase of treasury shares	-1,165	-994
Other financing activities, net	0	83
Net cash flow provided by (used for) financing activities	64,472	-67,486
Increase in cash and cash equivalents	2,260	7,033
Cash and cash equivalents, beginning of period	4,692	4,586
Cash and cash equivalents, end of period	6,952	11,619
Supplemental disclosure of non-cash transactions:
Dividends declared but not paid	13,053	11,377
Net change in accounts payable related to fixed asset additions	-3,674	2,537
Increase in consolidated net assets due to change in control	8,400	0
Deconsolidation of net assets	$0	$26,238

Business

Business	3 Months Ended
	Mar. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
BUSINESS	BUSINESS
	Except as the context otherwise requires, all references to "we," "our," "us," "AERC," "AEC" and the "Company" in this report collectively refer to Associated Estates Realty Corporation and its consolidated subsidiaries.
	We are a fully-integrated, self-administered and self-managed equity real estate investment trust ("REIT") specializing in multifamily ownership, operation, acquisition, development, disposition and property management activities. Our primary source of income is rental revenue. Additional income is derived from property management and construction services revenue. As of March 31, 2015, our operating portfolio consisted of 51 apartment communities containing 13,328 units in eight states that are owned, either directly or indirectly, through subsidiaries. In conjunction with our acquisition of land for development of an apartment community, we acquired a commercial building in Los Angeles, California, containing approximately 78,800 total square feet of office and commercial space. Additionally, we provide property management services for two apartment communities that we expect to acquire pursuant to existing contracts.

Significant_Accounting_Policie

Significant Accounting Policies	3 Months Ended
	Mar. 31, 2015
Accounting Policies [Abstract]
SIGNIFICANT ACCOUNTING POLICIES	SIGNIFICANT ACCOUNTING POLICIES
	Basis of Presentation
	The accompanying unaudited consolidated financial statements have been prepared by management in accordance with accounting principles generally accepted in the United States of America ("GAAP") for interim financial information and applicable rules and regulations of the Securities and Exchange Commission ("SEC"). Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. In the opinion of management, all adjustments consisting only of normal and recurring adjustments considered necessary for a fair statement have been included. The reported results of operations are not necessarily indicative of the results that may be expected for the full year. These financial statements should be read in conjunction with the audited financial statements and accompanying notes in our Annual Report on Form 10-K for the year ended December 31, 2014.
	Principles of Consolidation
	The Company follows the provisions of Accounting Standards Codification No. 810, Consolidation. This standard requires a company to perform an analysis to determine whether its variable interests give it a controlling financial interest in a Variable Interest Entity (“VIE”). This analysis identifies the primary beneficiary of a VIE as the entity that has the power to direct the activities of the VIE that most significantly affect the VIE’s economic performance and the obligation to absorb losses or the right to receive benefits that could potentially be significant to the VIE. In determining whether it has the power to direct the activities of the VIE that most significantly affect the VIE’s performance, this standard requires a company to assess whether it has an implicit financial responsibility to ensure that a VIE operates as designed. When an entity is not deemed to be a VIE, the Company considers the provisions to determine whether a general partner, or the general partners as a group, controls a limited partnership or similar entity when the limited partners have certain rights. Investments in real estate joint ventures in which the Company has the ability to exercise significant influence, but does not have financial or operating control, are accounted for using the equity method of accounting.
	Table of Contents
	Segment Reporting
	Substantially all of our properties are multifamily communities and, while the economic climate of the markets in which they are located may vary from time to time, the communities offer similar products and services and have similar economic characteristics. Management evaluates the performance of our properties and makes acquisition/disposition decisions on an individual basis. During the three months ended March 31, 2015, substantially all of our consolidated revenue was provided by our multifamily properties. We have determined that, as of March 31, 2015, we have one reportable segment which is multifamily properties.
	Discontinued Operations
	In April 2014, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2014-08, Presentation of Financial Statements (Topic 205) and Property, Plant and Equipment (Topic 360): Reporting of Discontinued Operations and Disclosures of Components of an Entity ("ASU 2014-08"). ASU 2014-08 states that only those disposals of components of an entity that represent a strategic shift that has (or will have) a major effect on an entity's operations and financial results should be reported as discontinued operations in the financial statements. Prior accounting guidance held that a component of an entity that is a reportable segment, an operating segment, a reporting unit, a subsidiary or an asset group was eligible for discontinued operations presentation. This led to many disposals, many of which were routine in nature and did not change an entity's strategy, to be reported as discontinued operations. The amendments in ASU 2014-08 require expanded disclosure for discontinued operations, which should provide financial statement users with more information about the assets, liabilities, revenues and expenses of discontinued operations. As such, our disposition of individual properties will generally no longer meet the guidance to be classified as discontinued operations. This updated guidance requires prospective application for all disposals of components of an entity that occur within annual periods beginning on or after December 15, 2014 and interim periods within those years, with early adoption permitted. We adopted this guidance effective January 1, 2014.
	Debt Issuance Costs
	In April 2015, the FASB issued ASU 2015-03, Interest - Imputation of Interest (Subtopic 835-30) ("ASU 2015-03"). In order to simplify presentation of debt issuance costs, ASU 2015-03 requires that debt issuance costs be presented in the balance sheet as a direct deduction from the carrying amount of debt liability, consistent with debt discounts or premiums, rather than as a deferred asset. This updated guidance requires retrospective application for all prior periods disclosed and will be effective for financial statements issued for fiscal years beginning after December 15, 2015. The amendments in ASU 2015-03 require disclosure over the nature of and reason for the change in accounting principle, the transition method, a description of the prior-period information that has been retrospectively adjusted and the effect of the change on the financial statement line items. ASU 2015-03 will become effective for the Company on January 1, 2016. The Company is currently evaluating the impact the adoption of ASU 2015-03 will have on the Company's financial position.

Acquisition_Development_and_Di

Acquisition, Development, and Disposition Activity	3 Months Ended
	Mar. 31, 2015
Acquisition, Development, and Disposition Activity [Abstract]
ACQUISITION, DEVELOPMENT, AND DISPOSITION ACTIVITY	ACQUISTION, DEVELOPMENT, AND DISPOSITION ACTIVITY
	Acquisition Activity
	On September 20, 2013, we entered into an agreement to acquire a portfolio of seven properties for a total purchase price of $323.9 million, including the assumption of $28.0 million of existing mortgage financing. During the year ended December 31, 2013, we closed on three of the seven properties: The Apartments at Blakeney, St. Mary's Square and Lofts at Weston Lakeside. During the year ended December 31, 2014, we closed on an additional two properties: Alpha Mill Phase I and Alpha Mill Phase II, which we operate as one property. During the three months ended March 31, 2015, we closed on one property: 1160 Hammond. We expect to acquire the remaining property based on the closing period set forth in the following table. This remaining closing is contingent upon the completed construction of the property. Our obligation to purchase this property is subject to certain closing conditions specified in the agreement. If we choose not to purchase the remaining property, despite the closing conditions having been satisfied within the time period contemplated by the purchase agreement, we would forfeit the then-remaining balance of our earnest money deposit, which was, as of March 31, 2015, $10.0 million. This remaining balance of our earnest money deposit represents our maximum exposure to loss until the closing of the remaining portfolio property. We consider our deposit allocated to the entity developing the property under construction to be a variable interest and the development entity to be a VIE for which we are not the primary beneficiary as of this reporting date as we do not have control over the entity. Although we intend to acquire the remaining property, and regard our acquisition as probable, there can be no assurance that we will acquire the property.
	The table below provides details for the remaining property we plan to acquire:
	(Dollar amounts in thousands)
	Property		Location		Units		Estimated Closing Period		Purchase Price
	Varela Westshore		Tampa, FL		350		Q2 2015		$	79,450
	During the year ended December 31, 2012, we entered into an agreement to acquire for a purchase price of $80.2 million a 331-unit property that is being developed in Ft. Lauderdale, Florida. Our purchase obligation is conditioned upon the successful completion of the property in accordance with agreed upon plans and specifications and up to an 18-month period to allow for lease up of the property. Closing will not occur unless the conditions are satisfied, which is currently expected to occur in February 2016. The developer may elect to terminate our agreement to purchase by agreeing to the release of our $4.0 million earnest money deposit from escrow and paying us an $8.0 million termination fee.  If we choose not to purchase the property, despite the closing conditions having been satisfied within the time period contemplated by the purchase agreement, we would forfeit our $4.0 million earnest money deposit.  This earnest money deposit represents our maximum exposure to loss until the closing of the property. We consider our deposit to be a variable interest and the development entity to be a VIE for which we are not the primary beneficiary as of this reporting date as we do not have control over the entity.
	On March 2, 2015, we acquired 1160 Hammond, a 345-unit property located in Atlanta, Georgia, for a total purchase price of $80.4 million. This acquisition was funded by borrowings from our unsecured revolving line of credit and proceeds from property dispositions held for a 1031 exchange.
	Table of Contents
	The following table represents the purchase price allocation for the property acquired during the three months ended March 31, 2015.
			Three Months Ended
			March 31,
	(In thousands)		2015
	Land		$	6,953
	Buildings and improvements		71,664
	Furniture and fixtures		1,270
	Existing leases (Other assets)		463
	Total		$	80,350
	The following table presents actual and pro forma information related to the property acquired during the three months ended March 31, 2015. The pro forma information is presented as if the property was acquired on January 1, 2014. We recognized acquisition costs during the three months ended March 31, 2015 totaling $57,000 related to this property, which are included in "Costs associated with acquisitions" in the Consolidated Statements of Operations and Comprehensive Income. Additionally, we recognized acquisition costs totaling $26,000 and $24,000 related to the current year acquisition during 2014 and 2013, respectively. The pro forma presentation is presented for informational purposes only, and is not necessarily indicative of what our actual results of operations would have been had the acquisition occurred at such time.
			Three Months Ended
			March 31,
	(In thousands, except per share amounts)		2015				2014
	Actual revenue from acquisitions		$	239			$	—
	Actual net loss from acquisitions		(252		)		—
	Pro forma revenue		48,581				50,306
	Pro forma net income applicable to common shares		420				42,201
	Pro forma earnings per common share - basic:
	Pro forma net income applicable to common shares		$	0.01			$	0.74
	Pro forma earnings per common share - diluted:
	Pro forma net income applicable to common shares		$	0.01			$	0.73
	Development Activity
	During the year ended December 31, 2013, we entered into a partnership agreement with an unrelated third-party for the limited purpose of acquiring a property in Monrovia, California, known as 5th and Huntington, and to produce construction drawings for improvements to the property. The land, upon which the partnership planned to develop a 154-unit multifamily apartment community, was purchased by the partnership on August 9, 2013 for $13.1 million. We held a 50.0% equity interest in the partnership, which was accounted for under the equity method. On February 3, 2015, we purchased our partner's 50.0% interest in 5th and Huntington for an agreed upon price of $8.4 million, increasing our ownership percentage in the development to 100%. We recognized a gain of $444,000 related to this acquisition, which represented the amount by which the $8.4 million fair value of our interest in the partnership exceeded our carrying value at the date of acquisition. The gain is included in "Gain on change in control" in the Consolidated Statements of Operations and Comprehensive Income. As of March 31, 2015, this development project is fully consolidated in our financial statements.
	Table of Contents
	On May 28, 2013, we acquired a 3.36-acre parcel of land in the SoMa neighborhood of San Francisco, California for $46.6 million. On February 2, 2014, we entered into a 50/50 partnership with AIG to develop and own this site known as 350 8th. The partnership is developing a 410-unit apartment community with 40,000 square feet commercial space and underground parking. See Note 6 for additional information related to this partnership.
	The following table identifies our consolidated development activity on which construction has commenced or completed:
	(Dollar amounts in thousands)									Total										Actual/
										Estimated								Actual		Estimated
	Under				Ownership		Total			Capital			Cost to			Total		Construction		Construction
	Construction		Location		%		Units			Cost (1)			Date			Debt		Start		Completion
	Cantabria at Turtle Creek		Dallas, TX		100.00%		249			$	55,904		$	55,874		$	36,335	Q2 2013		Q1 2015
	7001 Arlington at Bethesda		Bethesda, MD		98.10%	(2)	140			53,400			49,639			23,085		Q4 2012		Q2 2015
	The Desmond on Wilshire		Los Angeles, CA		100.00%		175			76,300			51,474			—		Q2 2013		Q4 2015
	Total						564			$	185,604		$	156,987		$	59,420
	-1	Total capital costs are calculated as if owned 100% by AEC and represent estimated costs for projects under development inclusive of all capitalized costs in accordance with GAAP. Based on current projections as of May 1, 2015.
	-2	Ownership percentage is based on expected total equity of the joint venture and is subject to change based on changes in total equity. Costs are shown at 100%. Joint venture partner contribution is $350.
	The following table identifies our unconsolidated development activity on which construction has commenced:
	(Dollar amounts in thousands)									Total
										Estimated			Cost			AEC					AEC				Actual	Estimated
	Under				Ownership		Total			Capital			to			Investment		Total			Share				Construction	Construction
	Construction		Location		%		Units			Cost (1)			Date			to Date		Debt			of Debt				Start	Completion
	350 8th		San Francisco, CA		50.01%		410			$	245,000		$	97,528		$	45,570	$	—		$	—	(2	)	Q2 2014	Q4 2016
	950 East Third		Los Angeles, CA		50.00%		472			164,000			40,272			9,514		—			—				Q3 2014	Q1 2017
	Total						882			$	409,000		$	137,800		$	55,084	$	—		$	—
	-1	Total capital costs are calculated as if owned 100% by AEC and represent estimated costs for projects under development inclusive of all capitalized costs in accordance with GAAP. Based on current projections as of May 1, 2015.
	-2	AEC has guaranteed 100% of a $143.6 million construction loan which had no outstanding balance as of March 31, 2015.
	Table of Contents
	The following table identifies our consolidated development activity that is in the planning phase:
	(Dollar amounts in thousands)
					Ownership		Estimated			Cost to				Total
	Name		Location		%		Total Units (1)			Date				Debt
	5th and Huntington		Monrovia, CA		100.00%		154			$	16,546	(2	)	$	—
	Warner Center		Woodland Hills, CA		100.00%		379			18,825				—
	Total						533			$	35,371			$	—
-1	Based on current projections as of May 1, 2015.
-2	Does not include the $444 gain change in control related to the acquisition of our partner's interest.
Capitalized Interest and Development Payroll. Total capitalized interest during the three months ended March 31, 2015 and 2014 was $1.4 million and $1.0 million, respectively. Capitalized payroll costs, including share-based compensation, are allocated to projects based upon time incurred by the applicable personnel. Capitalized costs related to development and construction are transferred to buildings and improvements and/or furniture and fixtures, as applicable, upon substantial completion of the project, (i.e., certificate of occupancy has been obtained). Total capitalized payroll costs during the three months ended March 31, 2015 and 2014 were $980,000 and $770,000, respectively.
Disposition Activity
During the three months ended March 31, 2014, we completed the sale of one property, located in Maryland, for a total sales price of $60.0 million and recognized a gain of $41.0 million.
We classify properties as held for sale when all significant contingencies surrounding the completion of the disposition have been resolved. We discontinue the depreciation of assets we have specifically identified as held for sale. There was one property classified as held for sale at March 31, 2015 and no properties classified as held for sale at December 31, 2014.
We have, on occasion, engaged Hancock Real Estate Strategies ("HRES"), a full service investment real estate brokerage and advisory firm, to provide certain real estate brokerage services. HRES is owned by Matthew E. Friedman, a son of our Chief Executive Officer ("CEO"). While no commissions were paid to HRES for the three months ended March 31, 2015, a commission totaling $319,000 was paid in conjunction with the sale of one property in southeast Michigan for $16.5 million on April 6, 2015. See Note 14 for further details on this property sale. This transaction was approved by the Company's independent directors in compliance with Company policy. No commissions were paid to HRES for the three months ended March 31, 2014.

Debt

Debt	3 Months Ended
	Mar. 31, 2015
Debt Disclosure [Abstract]
DEBT	DEBT
	The following table identifies our total debt outstanding and weighted average interest rates:
		March 31, 2015					December 31, 2014
					Weighted				Weighted
		Balance			Average Interest		Balance		Average Interest
	(Dollar amounts in thousands)	Outstanding			Rate		Outstanding		Rate
	Fixed Rate Debt:
	Secured	$	223,167		4.8	%	$	223,934	4.8	%
	Unsecured - notes	250,000			4.4	%	250,000		4.4	%
	Total Fixed Rate Debt	473,167			4.6	%	473,934		4.6	%
	Variable Rate Debt Swapped to Fixed:
	Unsecured - term loan (1) (2)	125,000			2.7	%	125,000		2.7	%
	Unsecured - term loan (3)	25,000			1.6	%	—		—	%
	Total Variable Rate Debt Swapped to Fixed	150,000			2.4	%	125,000		2.7	%
	Variable Rate Debt Unhedged:
	Secured	59,420			1.5	%	48,679		1.5	%
	Unsecured - revolving credit facility	144,000			1.5	%	76,500		1.5	%
	Unsecured - term loan (3)	—		—	—	%	25,000		1.6	%
	Total Variable Rate Debt Unhedged	203,420			1.5	%	150,179		1.5	%
	Total Debt	$	826,587		3.5	%	$	749,113	3.7	%
	-1	The Company entered into a forward starting swap in December 2011 fixing the rate beginning in June 2013 until June 2016 at a rate of 1.26% per annum plus the credit spread which was 1.40% per annum as of March 31, 2015, or an all-in rate of 2.66% per annum. Additionally, the Company entered into a forward starting swap in April 2013 fixing the rate beginning June 2016 at a rate of 1.55% per annum plus the credit spread which was 1.40% per annum as of March 31, 2015, or an all-in rate of 2.95% per annum until January 2018.
	-2	The Company entered into a forward starting swap in January 2015 fixing the rate beginning January 2018 at a rate of 1.75% per annum plus the credit spread which was 1.40% per annum as of March 31, 2015, or an all-in rate of 3.15% per annum until the loan matures in January 2020.
	-3	The Company entered into a forward starting swap in January 2015 fixing the rate beginning January 2016 at a rate of 1.42% per annum plus the credit spread which was 1.40% per annum as of March 31, 2015, or an all-in rate of 2.82% per annum until the loan matures in January 2020.
	Mortgage Notes Payable
	On April 25, 2014, the 350 8th partnership, in which we are a 50.01% partner and that we account for under the equity method, entered into a construction loan agreement for $143.6 million with a five-year term and, based on our current credit ratings, has a per annum interest rate of LIBOR plus 160 basis points. There were no borrowings on this loan as of March 31, 2015. We have guaranteed the payment of all future borrowings from this loan and the completion of construction in connection with the partnership's development. Additionally, we have drawn $36.3 million on the Cantabria at Turtle Creek construction loan and $23.1 million on the 7001 Arlington at Bethesda construction loan as of March 31, 2015. Cash paid for interest net of capitalized interest was $6.2 million and $7.3 million for the three months ended March 31, 2015 and 2014, respectively.

Goodwill_and_Other_Intangible_

Goodwill and Other Intangible Assets	3 Months Ended
	Mar. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
GOODWILL AND OTHER INTANGIBLE ASSETS	GOODWILL AND OTHER INTANGIBLE ASSETS
	Goodwill
	Our goodwill was allocated to our properties on a relative fair value basis. Upon disposition of properties, the goodwill allocated is included in the calculation of the gain or loss on disposal and subsequently written off. As there were no property dispositions during the three months ended March 31, 2015, there was no write-off of goodwill. The carrying value of our goodwill as of March 31, 2015 and December 31, 2014 was $1.3 million. Our annual review of goodwill impairment is completed during the first quarter of each year (and more frequently if events or changes in circumstances indicate the carrying value may not be recoverable). The review, completed during the three months ended March 31, 2015, determined that goodwill was not impaired, and no other events have occurred that would require goodwill to be reevaluated. In performing this analysis, we compare the net assets of each property on which goodwill has been allocated, including the amount of allocated goodwill, to its estimated fair market value. Should the estimates used to determine the fair value of the properties change, impairment may result, which could impact our results of operations for the period in which it is recorded.
	Intangible Assets
	We allocate a portion of the total purchase price of a property acquisition to any intangible assets identified, such as existing leases. The intangible assets are amortized over the remaining lease terms, which are approximately 6 to 12 months. Due to the short-term nature of residential leases, we believe existing lease rates approximate market rates. Therefore, no allocation is made for above/below market leases. The intangible assets associated with one commercial lease are being amortized over the life of the lease, which is 60 months. See Note 13 for additional information related to this lease.

Investment_in_Unconsolidated_E

Investment in Unconsolidated Entities Investment in Unconsolidated Entities	3 Months Ended
	Mar. 31, 2015
Schedule of Equity Method Investments [Line Items]
INVESTMENT IN UNCONSOLIDATED ENTITIES	INVESTMENT IN UNCONSOLIDATED ENTITIES
	The following table identifies our investment in unconsolidated entities as of March 31, 2015:
	(Dollar amounts in thousands)					Partner				Construction		Cumulative		Maximum
				Ownership	Total	Contribution				Management Fee		Basis Difference		Exposure
	Partnership		Location	%	Units	to Date				Recognized to Date		to Date		to Loss
	350 8th		San Francisco, CA	50.01%	410	$	44,300			$	460	$	1,250	$	45,570
	950 East Third		Los Angeles, CA	50.00%	472	30,000		(1	)	375		530		9,514
	Total				882	$	74,300			$	835	$	1,780	$	55,084
	-1	Land valued at $30.0 million was contributed by our partner, Legendary Investors Group No. 1 LLC ("Legendary"), to the partnership.
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	350 8th
	On February 3, 2014, we entered into a partnership agreement with AIG, an unrelated third-party, for the development and operation of 350 8th, an apartment community with 40,000 square feet of commercial space and underground parking located in San Francisco, California. The land upon which the partnership is developing was purchased by us for $46.6 million on May 28, 2013. Upon the formation of our partnership with AIG, the land and improvements to date, with a carrying value of $50.3 million, were deconsolidated. Any future equity capital needs will be funded according to the partners' percentage interests in the partnership. On April 25, 2014, the partnership entered into a construction loan agreement for $143.6 million with a five-year term. There were no borrowings on this loan at March 31, 2015. We have guaranteed the payment of all future borrowings from this loan and the completion of construction in connection with the partnership's development. See Note 4 for more information related to this loan and Note 13 for more information related to the guarantees.
	950 East Third
	During the year ended December 31, 2013, we entered into a partnership agreement with Legendary, an unrelated third-party, for the development and operation of 950 East Third, an apartment community located in Los Angeles, California. We expect to fund the remaining portion of our capital contribution during the development and construction process.
	Investment in Unconsolidated Entities
	As the 350 8th and 950 East Third partnerships are not sufficiently funded to finance the activities of the entities, and not all of the capital will be funded up front, the partnerships are not deemed to have sufficient equity, and have therefore been determined to be VIEs. We have equal voting rights with respect to all major decisions in both partnerships, and all such decisions must be unanimous, including, among other things, development planning, budgeting and operational budgets. It has also been determined that we do not control the decisions that most significantly affect the economics of either entity, and that we do not hold a controlling financial interest in either entity. As such, our investments in the entities are accounted for in our consolidated financial statements using the equity method.
	We perform construction management and property management services for both partnerships in accordance with the approved budgets for which we receive fees.
	The cumulative basis differences in the partnerships are due to capitalization of interest on our investment and internal payroll and overhead costs directly related to the development of the properties. This excess of our investment over our equity in the underlying net assets of the joint ventures is included in "Investment in unconsolidated entities" in our Consolidated Balance Sheets, and will be amortized as a reduction to earnings on a straight-line basis over the lives of the related assets.
	Our maximum exposure to loss, as a result of our involvement in these entities, is the carrying value of our investment. See Note 3 for more information related to these unconsolidated development projects.

Noncontrolling_Interests

Noncontrolling Interests	3 Months Ended
	Mar. 31, 2015
Noncontrolling Interest [Abstract]
NONCONTROLLING INTERESTS	NONCONTROLLING INTERESTS
	On July 14, 2011, we entered into a partnership agreement with Keating Project Development, Inc., an unrelated third-party, pursuant to which we hold a 98.1% equity interest in the partnership. In March 2012, the partnership acquired a 2.5-acre parcel of land in Bethesda, Maryland for $12.2 million on which it is developing 140 apartment units and 6,898 square feet of commercial space. We have determined that this entity is not a VIE and that we hold a controlling interest in the entity. As such, this entity is included in our consolidated financial statements. We have also determined that the noncontrolling interest in this entity, which as of March 31, 2015 and 2014 was $350,000, meets the criteria to be classified as a component of permanent equity.

Equity

Equity	3 Months Ended
	Mar. 31, 2015
Equity [Abstract]
EQUITY	EQUITY
	The following table provides a reconciliation of significant activity in equity accounts:
		Three Months Ended March 31, 2015
		Common				Accumulated
		Shares				Distributions			Accumulated
		(at $.10				in Excess of			Other			Treasury
		stated		Paid-in		Accumulated			Comprehensive			Shares			Noncontrolling
	(In thousands)	value)		Capital		Net Income			Loss			(at Cost)			Interest
	Balance, December 31, 2014	$	5,771	$	758,079	$	(114,551	)	$	(1,093	)	$	(980	)	$	350
	Net income applicable to common shares	—		—		744			—			—			—
	Other comprehensive income:
	Change in fair value of hedge
	instruments	—		—		—			(136		)	—			—
	Share-based compensation	—		1,447		—			—			1,055			—
	Purchase of common shares	—		—		—			—			(1,165		)	—
	Issuance of common shares	22		—		—			—			—			—
	Common share dividends declared	—		—		(12,277		)	—			—			—
	Balance, March 31, 2015	$	5,793	$	759,526	$	(126,084	)	$	(1,229	)	$	(1,090	)	$	350

Earnings_Per_Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
EARNINGS PER SHARE	EARNINGS PER SHARE
	The following table presents a reconciliation of basic and diluted earnings per common share:
		Three Months Ended
		March 31,
	(In thousands, except per share amounts)	2015		2014
	Numerator - basic and diluted:
	Net income	$	744	$	42,273
	Allocation to participating securities	—		(157		)
	Net income applicable to common shares	$	744	$	42,116
	Denominator - basic:	57,612		57,362
	Effect of dilutive securities (1)	613		471
	Denominator - diluted:	58,225		57,833
	Net income applicable to common shares - basic:
	Net income applicable to common shares - basic	$	0.01	$	0.73
	Net income applicable to common shares - diluted:
	Net income applicable to common shares - diluted	$	0.01	$	0.73
	-1	The Company has excluded 42 stock options for the three months ended March 31, 2014 as their inclusion would be anti-dilutive.

Equity_Based_Award_Plans

Equity Based Award Plans	3 Months Ended
	Mar. 31, 2015
Share-based Compensation [Abstract]
EQUITY BASED AWARD PLANS	EQUITY BASED AWARD PLANS
	During each of the three months ended March 31, 2015 and 2014, we recognized share-based compensation cost of $1.3 million in "General and administrative" expense in the Consolidated Statements of Operations and Comprehensive Income. Additionally, during the three months ended March 31, 2015 and 2014, we capitalized $300,000 and $100,000, respectively, of share-based compensation related to time incurred on development projects. See Note 3 for additional information related to capitalized payroll.
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	Restricted Shares. Restricted shares generally have the same rights as our common shares, except for transfer restrictions and forfeiture provisions. We have two compensation plans under which our officers and directors may elect to defer the receipt of restricted shares. Restricted share awards deferred under these plans are reflected as deferred restricted share equivalent units ("DRSUs") in an individual bookkeeping account maintained for each participant. The vesting of DRSUs occurs on the same schedule as the restricted shares made subject to the deferral election, and the valuation and attribution of cost in our consolidated financial statements are also the same as the restricted shares subject to the deferral election. DRSUs are not included in the number of issued and outstanding common shares reflected in the "Equity" section of our Consolidated Balance Sheets. DRSUs with non-forfeitable dividend rights are included in the allocation to participating securities using the two-class method. DRSUs with forfeitable dividend rights do not qualify as participating securities, and are included in the calculation of diluted earnings per share to the extent they are not anti-dilutive for the period presented.
	The following table represents restricted share and DRSU activity for the three months ended March 31, 2015:
				Weighted			Weighted
		Number of		Average			Average
		Restricted		Grant-Date		Number of	Grant-Date
		Shares		Fair Value		DRSUs	Fair Value
	Nonvested at beginning of period	702,860		$	10.31	45,365	$	17.06
	Granted	100,618		$	24.71	13,249	$	24.27
	Vested	134,378		$	18.32	7,235	$	20.17
	Forfeited	10,021		$	10.73	1,192	$	17.46
	Nonvested at end of period	659,079		$	10.87	50,187	$	18.51
	The weighted average grant-date fair value of restricted shares granted during the three months ended March 31, 2014 was $16.00. The total fair value of restricted shares vested during the three months ended March 31, 2015 and 2014 was $3.3 million and $2.5 million, respectively. The total fair value of DRSUs vested during the three months ended March 31, 2015 and 2014 was $174,000 and $90,000, respectively, recognized as "Paid-in capital." At March 31, 2015, there was a total of $6.1 million of unrecognized compensation cost related to nonvested restricted share awards and DRSUs that we expect to recognize over a weighted average period of 2.2 years. See Note 14 for additional information related to the Agreement and Plan of Merger entered into by the the Company on April 22, 2015.
	During 2014 and 2013, we issued restricted share awards in which the number of shares that will ultimately vest is subject to market conditions over a three-year period and service conditions over a four-year period. The total estimated grant-date fair value of these awards, including the awards that were deferred, were $90,000 during 2014 and $4.3 million during 2013. We used the Monte Carlo method to estimate the fair value of these awards. The Monte Carlo method, which is similar to the binomial analysis, evaluates the award for changing stock prices over the term of vesting, and uses random situations that are averaged based on past stock characteristics. There were one million simulation paths used to estimate the fair value of these awards. The expected volatility for the awards granted in 2014 and 2013 was based upon a 50/50 blend of historical and implied volatility. The historical volatility was based upon changes in the weekly closing prices of our shares over a period equal to the expected life of the restricted shares granted. The implied volatility was the trailing month average of daily implied volatilities calculated by interpolating between the volatilities implied by stock call option contracts that were closest to both the expected life and the exercise price of the restricted shares. The risk-free interest rate used was based on a yield curve derived from U.S. Treasury zero-coupon bonds on the date of grant with a maturity equal to the market condition performance periods. The expected life used was the market condition performance period.
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	The following table represents the assumption ranges used in the Monte Carlo method for the multi-year restricted share awards:
		2014	2013
	Expected volatility - AERC	22.3% to 24.2%	18.1% to 22.5%
	Expected volatility - peer group	16.9% to 24.7%	14.7% to 29.5%
	Risk-free interest rate	0.02% to 0.8%	0.08% to 0.5%
	Expected life (performance period)	3 years	3 years
	Stock Options. We use the Black-Scholes option pricing model to estimate the fair value of stock options awarded. There were no options awarded, no options exercised and no options forfeited during the three months ended March 31, 2015. There were no options awarded, no options exercised and 5,000 options forfeited during the three months ended March 31, 2014.
	The following table represents stock option activity for the three months ended March 31, 2015:
						Weighted-Average
		Number of		Weighted-Average		Remaining
		Stock Options		Exercise Price		Contract Life
	Outstanding at beginning of period	360,376		$	11.29
	Exercised	—		$	—
	Forfeited	—		$	—
	Outstanding at end of period	360,376		$	11.29	1.8
	Exercisable at end of period	360,376		$	11.29	1.8
	The aggregate intrinsic value of stock options outstanding and stock options exercisable at March 31, 2015 and 2014 was $4.8 million and $2.6 million, respectively.

Derivative_Instruments_and_Hed

Derivative Instruments and Hedging Activities	3 Months Ended
	Mar. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES	DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES
	We utilize interest rate swaps, from time to time, to add stability to interest risk and to manage our exposure to interest rate movements.
	As of March 31, 2015, the Company had the following outstanding interest rate derivatives that were designated as cash flow hedges:
	Interest Rate Derivative		Number of Instruments		Notional Amount
	Interest Rate Swaps		4		$150.0 million
	On January 30, 2015, we entered into a forward starting interest rate swap on $25.0 million of our $150 million unsecured term loan, fixing the rate beginning January 2016 at a rate of 1.42% per annum plus the credit spread, which was 1.40% per annum as of March 31, 2015, or an all-in rate of 2.82% per annum until the loan matures in January 2020. Additionally, on January 30, 2015, we entered into a forward starting interest rate swap on $125.0 million of our $150 million unsecured term loan, fixing the rate beginning January 2018 at a rate of 1.75% per annum plus the credit spread, which was 1.40% per annum as of March 31, 2015, or an all-in rate of 3.15% per annum, through the maturity date of January 2020. The credit spread is subject to change, from time to time, from a minimum of 0.90% per annum to a maximum of 1.90% per annum over LIBOR based upon our qualified ratings as defined in the agreement.
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	On April 2, 2013, we entered into a forward starting interest rate swap on $125.0 million of our $150 million unsecured term loan, fixing the rate beginning June 2, 2016 at a rate of 1.55% per annum plus the credit spread, which was 1.40% per annum as of March 31, 2015, or an all-in rate of 2.95% per annum until January 2018. The credit spread is subject to change, from time to time, from a minimum of 0.90% per annum to a maximum of 1.90% per annum over LIBOR based upon our qualified ratings as defined in the agreement.
	On December 19, 2011, we entered into a forward starting interest rate swap effective June 7, 2013. This swap hedges the future cash flows of interest payments on $125.0 million of our $150 million unsecured term loan by fixing the rate until June 2016 at a rate of 1.26% per annum plus the credit spread, which was 1.40% per annum at March 31, 2015, or an all-in rate of 2.66% per annum. The credit spread is subject to change, from time to time, from a minimum of 0.90% per annum to a maximum of 1.90% per annum over LIBOR based upon our qualified ratings as defined in the agreement.
	The following table presents the fair value of our derivative financial instruments as well as the classification on the Consolidated Balance Sheets (see Note 12 for additional information regarding the fair value of these derivative instruments):
	Fair Value of Derivative Instruments
		Asset Derivatives
		As of March 31, 2015						As of December 31, 2014
	(In thousands)	Balance Sheet Location		Fair Value				Balance Sheet Location		Fair Value
	Derivatives designated
	as hedging instruments:
	Interest rate swap	Other assets, net		$	575			Other assets, net		$	256
	Fair Value of Derivative Instruments
		Liability Derivatives
		As of March 31, 2015						As of December 31, 2014
	(In thousands)	Balance Sheet Location		Fair Value				Balance Sheet Location		Fair Value
	Derivatives designated
	as hedging instruments:
		Accounts payable and						Accounts payable and
	Interest rate swap	other liabilities		$	1,804			other liabilities		$	1,349
	The following table presents the effect of our derivative financial instruments on the Consolidated Statements of Operations and Comprehensive Income:
	The Effect of Derivative Instruments on the Consolidated Statements of Operations and Comprehensive Income
			Location of Gain or
	(In thousands)		(Loss) Recognized		Three Months Ended
	Derivatives in Cash Flow Hedging		in Income		March 31,
	Relationships (Interest Rate Swaps)		on Derivative		2015				2014
	Amount of gain/(loss) recognized in OCI on derivative				$	(476	)		$	(407	)
	Amount of loss reclassified from accumulated
	OCI into interest expense		Interest expense		$	(340	)		$	(344	)
	Amount of gain/(loss) recognized in
	income on derivative (ineffective portion and
	amount excluded from effectiveness testing)		Other expense		$	—			$	—
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	The following table presents the effect of offsetting financial assets and liabilities on the Consolidated Balance Sheets:
	Offsetting of Derivative Assets and Liabilities
													Gross Amounts Not Offset in
											Net Amounts of		the Balance Sheets
			Gross Amounts				Gross Amounts				Assets/Liabilities				Cash
			of Recognized				Offset in the				Presented in the		Financial		Collateral		Net
	(In thousands)		Assets/Liabilities				Balance Sheets				Balance Sheets		Instruments		Received		Amount
	31-Mar-15
	Offsetting Derivative
	Assets		$	575			$	—			$	575	$	—	$	—	$	575
	Liabilities		$	1,804			$	—			$	1,804	$	—	$	—	$	1,804
	31-Dec-14
	Offsetting Derivative
	Assets		$	256			$	—			$	256	$	—	$	—	$	256
	Liabilities		$	1,349			$	—			$	1,349	$	—	$	—	$	1,349
	As of March 31, 2015, the fair value of the derivative in a liability position, excluding any adjustment for nonperformance risk, was $1.9 million. As of March 31, 2015, we have not posted any collateral related to this agreement.  If we had breached any of the provisions in the agreement with our derivative counterparty at March 31, 2015, we could have been required to settle our obligations under the agreement at its termination value of $1.9 million, which includes accrued interest of $87,000.  The expected amount of other comprehensive income to be reclassified as earnings within the next twelve months is $1.2 million.

Fair_Value

Fair Value	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
FAIR VALUE	FAIR VALUE
	Fair value, as defined by GAAP, represents the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. The inputs used in the determination of fair value amounts and disclosures are based on the assumptions that market participants would use when pricing certain assets or liabilities. These inputs are classified in the fair value hierarchy as follows:
	•	Level 1 inputs utilize quoted prices (unadjusted) in active markets for identical assets or liabilities that we have the ability to access;
	•	Level 2 inputs may include quoted prices for similar assets and liabilities in active markets, as well as interest rates and yield curves that are observable at commonly quoted intervals; and
	•	Level 3 inputs are unobservable inputs for the asset or liability that are typically based on an entity's own assumptions as there is little, if any, related market activity.
	The inputs used in the fair value measurement should be from the highest level available.  In instances where the measurement is based on inputs from different levels of the fair value hierarchy, the fair value measurement will fall within the lowest level input that is significant to the fair value measurement in its entirety.
	Cash, accounts and notes receivable, other assets, accounts payable, accrued expenses and other liabilities (except for the interest rate swap discussed below) are carried at amounts that reasonably approximate corresponding fair values because of their short-term nature.
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	The interest rate swap derivatives, as discussed in detail in Note 11 under "Derivative Instruments and Hedging Activities," are carried at fair value. The fair value of the derivative was determined by using a model that applies discount rates to the expected future cash flows associated with the swap. The significant inputs used in the valuation model to estimate the discount rates and expected cash flows are observable in active markets and, therefore, are Level 2 inputs.
	We estimate the fair value of our mortgage notes payable by discounting the associated cash flows using the interest rates available to us as of the dates reported for issuance of debt with similar terms, remaining maturities and loan to value ratios, which ranged from 41% to 52% at March 31, 2015. We classify the fair value of our mortgage notes payable as Level 3.
	We estimate the fair value of our unsecured debt by discounting the associated cash flows using the interest rates available to us as of the dates reported for issuance of debt with similar terms and remaining maturities. We classify the fair value of our unsecured debt as Level 2.
					Fair Value at March 31, 2015 Using
					Quoted Prices in
					Active Markets		Significant
					for Identical		Other		Significant
					Assets or		Observable		Unobservable
			Carrying		Liabilities		Inputs		Inputs
	(In thousands)		Value		(Level 1)		(Level 2)		(Level 3)
	Mortgage notes payable		$	282,587	$	—	$	—	$	295,168
	Unsecured debt		$	544,000	$	—	$	561,217	$	—
					Fair Value at December 31, 2014 Using
					Quoted Prices in
					Active Markets		Significant
					for Identical		Other		Significant
					Assets or		Observable		Unobservable
			Carrying		Liabilities		Inputs		Inputs
	(In thousands)		Value		(Level 1)		(Level 2)		(Level 3)
	Mortgage notes payable		$	272,613	$	—	$	—	$	283,728
	Unsecured debt		$	476,500	$	—	$	489,558	$	—

Contingencies

Contingencies	3 Months Ended
	Mar. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
CONTINGENCIES	CONTINGENCIES
	Legal Proceedings
	In conjunction with our May 2012 acquisition of land for development of an apartment community, we acquired a commercial building in Los Angeles, California (the "Property"), and entered into a triple net master lease (the "Lease") of the Property as landlord with Art and Architecture Books of the 21st Century as tenant ("Tenant").
	When Tenant failed to pay December 2012 rent when due under the Lease, we served Tenant with a notice to pay rent or vacate the premises pursuant to the California Code of Civil Procedure. On December 20, 2012, we filed an unlawful detainer action in the Superior Court for the State of California. Tenant did not pay rent for January or February 2013.
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	On February 19, 2013 (the scheduled trial date for our unlawful detainer suit), Tenant filed its Chapter 11 petition with the U.S. Bankruptcy Court (the "Bankruptcy Court") for the Central District of California.
	On March 29, 2013, Tenant filed a motion to assume the Lease. We opposed Tenant’s lease assumption motion. On September 12, 2013, the Bankruptcy Court granted Tenant’s motion to assume the Lease. We appealed the Bankruptcy Court’s order granting Tenant’s motion to assume the Lease to the U.S. District Court for the Central District of California (the “District Court”). On December 2, 2013, the District Court ruled in our favor and held the Bankruptcy Court had erred when it concluded the Lease had not been terminated prior to the date Tenant filed its Chapter 11 petition. Tenant appealed the District Court's decision to the U.S. Court of Appeals for the Ninth Circuit. The District Court remanded the case back to the Bankruptcy Court for further proceedings consistent with the District Court’s determination. On October 27, 2014, the Bankruptcy Court, on the matter remanded by the District Court, denied Tenant's lease assumption motion. Tenant has appealed the Bankruptcy Court's decision, and petitioned the Bankruptcy Court for a stay pending the outcome of Tenant's appeals. On December 29, 2014, the Bankruptcy Court granted Tenant's motion for stay pending the appeals, which stayed the effect of the Bankruptcy Court's denial of Tenant's lease assumption motion, including the requirement that Tenant surrender the Property.
	If we conclude, based on the outcome of this proceeding, that it is unlikely Tenant will remain at the Property, we will accelerate the amortization of the remaining intangible asset associated with the Lease at that time. The intangible asset is being amortized over the initial five-year term of the Lease, beginning May 2012, and had a balance of $794,000 at March 31, 2015. In addition, we may be required to refund to Tenant the $630,000 cure payment Tenant paid to us in connection with its assumption of the lease.
	In addition to the above, we are subject to other legal proceedings, lawsuits and other claims in the ordinary course of our business (collectively, "Litigation"). Litigation is subject to uncertainties and outcomes are difficult to predict. Many of the claims in Litigation are covered by insurance, subject to deductible amounts. With respect to current Litigation, we have determined either that a loss is not reasonably possible or that the estimated loss or range of loss, if any, will not have a material adverse impact on our financial statements.
	Guarantees
	On April 25, 2014, the 350 8th partnership, in which we are a 50.01% partner and that we account for under the equity method, entered into a construction loan agreement for $143.6 million with a five-year term. We have guaranteed the payment of all future borrowings from this loan and the completion of construction in connection with the partnership's development. We have determined that the fair value of these guarantees are immaterial and thus have not recorded any liability as of March 31, 2015.

Subsequent_Events

Subsequent Events	3 Months Ended
	Mar. 31, 2015
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	SUBSEQUENT EVENTS
	Dispositions. On April 6, 2015, we completed the sale of a property located in southeast Michigan. The sales price was $16.5 million and we expect to record an estimated gain of approximately $9.7 million during the second quarter of 2015.
	Dividends. On May 1, 2015, we paid a dividend of $0.21 per common share to shareholders of record on April 15, 2015, which had been declared on March 6, 2015. Due to the Plan of Merger discussed below, no future dividends are expected to be declared or paid.
	Plan of Merger. On April 22, 2015, the Company entered into an Agreement and Plan of Merger (the “Merger Agreement”) by and among the Company, BSREP II Aries Pooling LLC, a Delaware limited liability company (“Brookfield”), and BSREP II Aries DE Merger Sub Inc., a Delaware corporation and a wholly owned subsidiary of Brookfield (“Merger Sub”). Pursuant to the terms of the Merger Agreement, Merger Sub will be merged with and into the Company (the “Merger”), and the Company will continue as the surviving corporation and a wholly owned subsidiary of Brookfield.
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	Pursuant to the Merger Agreement:
	•	each common share of the Company (“Company Common Shares”) issued and outstanding at the effective time of the Merger (the “Effective Time”), other than Company Common Shares held (a) in the treasury of the Company, (b) by Brookfield or any subsidiary of Brookfield or (c) shareholders who have effectively exercised dissenter’s rights, will be canceled and extinguished and converted into the right to receive $28.75 in cash (the “Per Share Merger Consideration”), without interest;
	•	each option to purchase Company Common Shares (“Option”) that is outstanding and unexercised at the Effective Time (whether vested or unvested) will become fully vested and be cancelled, extinguished and converted into the right of the holder to receive an amount in cash, without interest, equal to the product of (i) the total number of Company Common Shares issuable upon exercise of such Option and (ii) the excess, if any, of the Per Share Merger Consideration over the exercise price per share of such Option;
	•	each share of restricted stock granted under any Company equity plan (“Restricted Share”) that is outstanding immediately before the Effective Time (whether vested or unvested, and including restricted stock granted as dividends) will, as of immediately before the Effective Time, become vested and will be treated as an outstanding Company Common Share that will be canceled and extinguished and converted into the right to receive the Per Share Merger Consideration, without interest; to the extent the performance period relating to any Restricted Share that remains subject to performance-based vesting criteria (“Performance Restricted Share”) has not expired as of the Effective Time, the Performance Restricted Share will vest in that number of Company Common Shares determined as if the applicable performance-based vesting criteria had been achieved at the maximum level; to the extent the performance period relating to any Performance Restricted Share has expired as of the Effective Time, the Performance Restricted Share will vest in that number of Company Common Shares determined at the end of the performance period based on actual performance through the end of the performance period;
	•	any accrued but unpaid dividends and any interest earned thereon as of the Effective Time attributed to Performance Restricted Shares granted under any Company equity plan will be paid in cash to such holder promptly following the Effective Time;
	•	all equity-based awards deferred under any Company deferred compensation plan, and accounts that represent amounts notionally invested in Company Common Shares in the Directors' Deferred Compensation Plan, will become vested and no longer subject to restrictions, and will be adjusted and converted into the right to have the account credited with an amount denominated in cash equal to the product of (i) the total number of Company Common Shares deemed invested under or otherwise referenced by such account and (ii) the Per Share Merger Consideration, reduced to the extent applicable, but not below zero, by the exercise price applicable to such award(s).
	Each of Brookfield and the Company has made customary representations and warranties in the Merger Agreement. Each of Brookfield and the Company has agreed to use reasonable best efforts to cause the Merger to be consummated. The Company has also agreed to various covenants in the Merger Agreement, including, among other things, (i) to conduct its business in the ordinary course consistent with past practice during the period between the execution of the Merger Agreement and the closing of the Merger, (ii) to call a special meeting of the shareholders to adopt the Merger Agreement and (iii) not to solicit alternative acquisition proposals.
	The Merger Agreement includes a “no-shop” provision that restricts the Company’s ability to solicit alternative acquisition proposals, and to provide information or engage in discussions with third parties. The no-shop provision is subject to a “fiduciary-out” provision that allows the Company, under certain circumstances, to provide information and participate in discussions with respect to unsolicited alternative acquisition proposals.
	Table of Contents
	The Merger Agreement contains certain termination rights for both the Company and Brookfield. Upon termination under specified circumstances, the Company would be required to pay Brookfield a termination fee of $60 million. Further, if the Merger Agreement is terminated due to shareholder adoption of the Merger Agreement having not been obtained at the special meeting of the Company’s shareholders called for that purpose, the Company will be required to reimburse Brookfield for transaction expenses in the amount of $20 million. The Company’s reimbursement of Brookfield’s expenses would be credited against any termination fee that may become payable by Company.
	Brookfield has obtained equity and debt financing commitments for the transactions contemplated by the Merger Agreement. The aggregate proceeds of the equity commitment will be sufficient to fully finance the Merger and the other transactions contemplated thereby. Consummation of the Merger is not subject to a financing condition, but is subject to customary conditions to closing, including the adoption of the Merger Agreement by the Company’s shareholders. The affirmative vote of a majority of the Company’s outstanding shares is required to adopt the Merger Agreement.
	The Company is entitled to seek specific performance against Brookfield and Merger Sub in order to enforce their respective obligations under the Merger Agreement. The Company is also a named third party beneficiary of the equity commitment. In addition, Brookfield’s liability for any breaches of the Merger Agreement, up to the aggregate Per Share Merger Consideration amount, is guaranteed by certain affiliates of Brookfield.
	The Board of Directors of the Company (the “Board of Directors”) unanimously approved the Merger Agreement on April 21, 2015. On April 21, 2015, Citigroup Global Markets Inc. rendered a written opinion to the Board of Directors that, as of the date of such opinion, the consideration to be offered to the shareholders of the Company in the Merger is fair, from a financial point of view, to such shareholders.

Significant_Accounting_Policie1

Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2015
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation
	The accompanying unaudited consolidated financial statements have been prepared by management in accordance with accounting principles generally accepted in the United States of America ("GAAP") for interim financial information and applicable rules and regulations of the Securities and Exchange Commission ("SEC"). Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. In the opinion of management, all adjustments consisting only of normal and recurring adjustments considered necessary for a fair statement have been included. The reported results of operations are not necessarily indicative of the results that may be expected for the full year. These financial statements should be read in conjunction with the audited financial statements and accompanying notes in our Annual Report on Form 10-K for the year ended December 31, 2014.
Principles of Consolidation	Principles of Consolidation
	The Company follows the provisions of Accounting Standards Codification No. 810, Consolidation. This standard requires a company to perform an analysis to determine whether its variable interests give it a controlling financial interest in a Variable Interest Entity (“VIE”). This analysis identifies the primary beneficiary of a VIE as the entity that has the power to direct the activities of the VIE that most significantly affect the VIE’s economic performance and the obligation to absorb losses or the right to receive benefits that could potentially be significant to the VIE. In determining whether it has the power to direct the activities of the VIE that most significantly affect the VIE’s performance, this standard requires a company to assess whether it has an implicit financial responsibility to ensure that a VIE operates as designed. When an entity is not deemed to be a VIE, the Company considers the provisions to determine whether a general partner, or the general partners as a group, controls a limited partnership or similar entity when the limited partners have certain rights. Investments in real estate joint ventures in which the Company has the ability to exercise significant influence, but does not have financial or operating control, are accounted for using the equity method of accounting.
Segment Reporting	Segment Reporting
	Substantially all of our properties are multifamily communities and, while the economic climate of the markets in which they are located may vary from time to time, the communities offer similar products and services and have similar economic characteristics. Management evaluates the performance of our properties and makes acquisition/disposition decisions on an individual basis. During the three months ended March 31, 2015, substantially all of our consolidated revenue was provided by our multifamily properties. We have determined that, as of March 31, 2015, we have one reportable segment which is multifamily properties.
New Accounting Pronouncements	Discontinued Operations
	In April 2014, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2014-08, Presentation of Financial Statements (Topic 205) and Property, Plant and Equipment (Topic 360): Reporting of Discontinued Operations and Disclosures of Components of an Entity ("ASU 2014-08"). ASU 2014-08 states that only those disposals of components of an entity that represent a strategic shift that has (or will have) a major effect on an entity's operations and financial results should be reported as discontinued operations in the financial statements. Prior accounting guidance held that a component of an entity that is a reportable segment, an operating segment, a reporting unit, a subsidiary or an asset group was eligible for discontinued operations presentation. This led to many disposals, many of which were routine in nature and did not change an entity's strategy, to be reported as discontinued operations. The amendments in ASU 2014-08 require expanded disclosure for discontinued operations, which should provide financial statement users with more information about the assets, liabilities, revenues and expenses of discontinued operations. As such, our disposition of individual properties will generally no longer meet the guidance to be classified as discontinued operations. This updated guidance requires prospective application for all disposals of components of an entity that occur within annual periods beginning on or after December 15, 2014 and interim periods within those years, with early adoption permitted. We adopted this guidance effective January 1, 2014.
	Debt Issuance Costs
	In April 2015, the FASB issued ASU 2015-03, Interest - Imputation of Interest (Subtopic 835-30) ("ASU 2015-03"). In order to simplify presentation of debt issuance costs, ASU 2015-03 requires that debt issuance costs be presented in the balance sheet as a direct deduction from the carrying amount of debt liability, consistent with debt discounts or premiums, rather than as a deferred asset. This updated guidance requires retrospective application for all prior periods disclosed and will be effective for financial statements issued for fiscal years beginning after December 15, 2015. The amendments in ASU 2015-03 require disclosure over the nature of and reason for the change in accounting principle, the transition method, a description of the prior-period information that has been retrospectively adjusted and the effect of the change on the financial statement line items. ASU 2015-03 will become effective for the Company on January 1, 2016. The Company is currently evaluating the impact the adoption of ASU 2015-03 will have on the Company's financial position.

Acquisition_Development_and_Di1

Acquisition, Development, and Disposition Activity (Tables)	3 Months Ended
	Mar. 31, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Purchase price allocation	The following table represents the purchase price allocation for the property acquired during the three months ended March 31, 2015.
			Three Months Ended
			March 31,
	(In thousands)		2015
	Land		$	6,953
	Buildings and improvements		71,664
	Furniture and fixtures		1,270
	Existing leases (Other assets)		463
	Total		$	80,350
	The table below provides details for the remaining property we plan to acquire:
	(Dollar amounts in thousands)
	Property		Location		Units		Estimated Closing Period		Purchase Price
	Varela Westshore		Tampa, FL		350		Q2 2015		$	79,450
Pro forma information
			Three Months Ended
			March 31,
	(In thousands, except per share amounts)		2015				2014
	Actual revenue from acquisitions		$	239			$	—
	Actual net loss from acquisitions		(252		)		—
	Pro forma revenue		48,581				50,306
	Pro forma net income applicable to common shares		420				42,201
	Pro forma earnings per common share - basic:
	Pro forma net income applicable to common shares		$	0.01			$	0.74
	Pro forma earnings per common share - diluted:
	Pro forma net income applicable to common shares		$	0.01			$	0.73
Schedule of completed, current and planned development	The following table identifies our consolidated development activity on which construction has commenced or completed:
	(Dollar amounts in thousands)									Total										Actual/
										Estimated								Actual		Estimated
	Under				Ownership		Total			Capital			Cost to			Total		Construction		Construction
	Construction		Location		%		Units			Cost (1)			Date			Debt		Start		Completion
	Cantabria at Turtle Creek		Dallas, TX		100.00%		249			$	55,904		$	55,874		$	36,335	Q2 2013		Q1 2015
	7001 Arlington at Bethesda		Bethesda, MD		98.10%	(2)	140			53,400			49,639			23,085		Q4 2012		Q2 2015
	The Desmond on Wilshire		Los Angeles, CA		100.00%		175			76,300			51,474			—		Q2 2013		Q4 2015
	Total						564			$	185,604		$	156,987		$	59,420
	-1	Total capital costs are calculated as if owned 100% by AEC and represent estimated costs for projects under development inclusive of all capitalized costs in accordance with GAAP. Based on current projections as of May 1, 2015.
	-2	Ownership percentage is based on expected total equity of the joint venture and is subject to change based on changes in total equity. Costs are shown at 100%. Joint venture partner contribution is $350.
	The following table identifies our unconsolidated development activity on which construction has commenced:
	(Dollar amounts in thousands)									Total
										Estimated			Cost			AEC					AEC				Actual	Estimated
	Under				Ownership		Total			Capital			to			Investment		Total			Share				Construction	Construction
	Construction		Location		%		Units			Cost (1)			Date			to Date		Debt			of Debt				Start	Completion
	350 8th		San Francisco, CA		50.01%		410			$	245,000		$	97,528		$	45,570	$	—		$	—	(2	)	Q2 2014	Q4 2016
	950 East Third		Los Angeles, CA		50.00%		472			164,000			40,272			9,514		—			—				Q3 2014	Q1 2017
	Total						882			$	409,000		$	137,800		$	55,084	$	—		$	—
	-1	Total capital costs are calculated as if owned 100% by AEC and represent estimated costs for projects under development inclusive of all capitalized costs in accordance with GAAP. Based on current projections as of May 1, 2015.
	-2	AEC has guaranteed 100% of a $143.6 million construction loan which had no outstanding balance as of March 31, 2015.
	Table of Contents
	The following table identifies our consolidated development activity that is in the planning phase:
	(Dollar amounts in thousands)
					Ownership		Estimated			Cost to				Total
	Name		Location		%		Total Units (1)			Date				Debt
	5th and Huntington		Monrovia, CA		100.00%		154			$	16,546	(2	)	$	—
	Warner Center		Woodland Hills, CA		100.00%		379			18,825				—
	Total						533			$	35,371			$	—
	-1	Based on current projections as of May 1, 2015.
	-2	Does not include the $444 gain change in control related to the acquisition of our partner's interest.

Debt_Tables

Debt (Tables)	3 Months Ended
	Mar. 31, 2015
Debt Instrument [Line Items]
Outstanding debt instruments	The following table identifies our total debt outstanding and weighted average interest rates:
		March 31, 2015					December 31, 2014
					Weighted				Weighted
		Balance			Average Interest		Balance		Average Interest
	(Dollar amounts in thousands)	Outstanding			Rate		Outstanding		Rate
	Fixed Rate Debt:
	Secured	$	223,167		4.8	%	$	223,934	4.8	%
	Unsecured - notes	250,000			4.4	%	250,000		4.4	%
	Total Fixed Rate Debt	473,167			4.6	%	473,934		4.6	%
	Variable Rate Debt Swapped to Fixed:
	Unsecured - term loan (1) (2)	125,000			2.7	%	125,000		2.7	%
	Unsecured - term loan (3)	25,000			1.6	%	—		—	%
	Total Variable Rate Debt Swapped to Fixed	150,000			2.4	%	125,000		2.7	%
	Variable Rate Debt Unhedged:
	Secured	59,420			1.5	%	48,679		1.5	%
	Unsecured - revolving credit facility	144,000			1.5	%	76,500		1.5	%
	Unsecured - term loan (3)	—		—	—	%	25,000		1.6	%
	Total Variable Rate Debt Unhedged	203,420			1.5	%	150,179		1.5	%
	Total Debt	$	826,587		3.5	%	$	749,113	3.7	%

Investment_in_Unconsolidated_E1

Investment in Unconsolidated Entities (Tables) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015															Mar. 31, 2014	Dec. 31, 2014
	Units
Schedule of Equity Method Investments [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Table Text Block]	The following table identifies our investment in unconsolidated entities as of March 31, 2015:
	(Dollar amounts in thousands)					Partner				Construction		Cumulative		Maximum
				Ownership	Total	Contribution				Management Fee		Basis Difference		Exposure
	Partnership		Location	%	Units	to Date				Recognized to Date		to Date		to Loss
	350 8th		San Francisco, CA	50.01%	410	$	44,300			$	460	$	1,250	$	45,570
	950 East Third		Los Angeles, CA	50.00%	472	30,000		(1	)	375		530		9,514
	Total				882	$	74,300			$	835	$	1,780	$	55,084
	-1	Land valued at $30.0 million was contributed by our partner, Legendary Investors Group No. 1 LLC ("Legendary"), to the partnership.
Ownership percentage	50.00%																50.00%
Apartment units owned	13,328
Partner contribution	$74,300
Management fees revenue	315															87
Outside basis	1,780
Maximum exposure	$55,084

Equity_Tables

Equity (Tables)	3 Months Ended
	Mar. 31, 2015
Equity [Abstract]
Schedule of Stockholders Equity	The following table provides a reconciliation of significant activity in equity accounts:
		Three Months Ended March 31, 2015
		Common				Accumulated
		Shares				Distributions			Accumulated
		(at $.10				in Excess of			Other			Treasury
		stated		Paid-in		Accumulated			Comprehensive			Shares			Noncontrolling
	(In thousands)	value)		Capital		Net Income			Loss			(at Cost)			Interest
	Balance, December 31, 2014	$	5,771	$	758,079	$	(114,551	)	$	(1,093	)	$	(980	)	$	350
	Net income applicable to common shares	—		—		744			—			—			—
	Other comprehensive income:
	Change in fair value of hedge
	instruments	—		—		—			(136		)	—			—
	Share-based compensation	—		1,447		—			—			1,055			—
	Purchase of common shares	—		—		—			—			(1,165		)	—
	Issuance of common shares	22		—		—			—			—			—
	Common share dividends declared	—		—		(12,277		)	—			—			—
	Balance, March 31, 2015	$	5,793	$	759,526	$	(126,084	)	$	(1,229	)	$	(1,090	)	$	350

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
Earnings Per Share	The following table presents a reconciliation of basic and diluted earnings per common share:
		Three Months Ended
		March 31,
	(In thousands, except per share amounts)	2015		2014
	Numerator - basic and diluted:
	Net income	$	744	$	42,273
	Allocation to participating securities	—		(157		)
	Net income applicable to common shares	$	744	$	42,116
	Denominator - basic:	57,612		57,362
	Effect of dilutive securities (1)	613		471
	Denominator - diluted:	58,225		57,833
	Net income applicable to common shares - basic:
	Net income applicable to common shares - basic	$	0.01	$	0.73
	Net income applicable to common shares - diluted:
	Net income applicable to common shares - diluted	$	0.01	$	0.73
	-1	The Company has excluded 42 stock options for the three months ended March 31, 2014 as their inclusion would be anti-dilutive

Equity_Based_Award_Plans_Table

Equity Based Award Plans (Tables)	3 Months Ended
	Mar. 31, 2015
Share-based Compensation [Abstract]
Restricted Share Activity	The following table represents restricted share and DRSU activity for the three months ended March 31, 2015:
				Weighted			Weighted
		Number of		Average			Average
		Restricted		Grant-Date		Number of	Grant-Date
		Shares		Fair Value		DRSUs	Fair Value
	Nonvested at beginning of period	702,860		$	10.31	45,365	$	17.06
	Granted	100,618		$	24.71	13,249	$	24.27
	Vested	134,378		$	18.32	7,235	$	20.17
	Forfeited	10,021		$	10.73	1,192	$	17.46
	Nonvested at end of period	659,079		$	10.87	50,187	$	18.51
Assumptions used in Monte Carlo method	The following table represents the assumption ranges used in the Monte Carlo method for the multi-year restricted share awards:
		2014	2013
	Expected volatility - AERC	22.3% to 24.2%	18.1% to 22.5%
	Expected volatility - peer group	16.9% to 24.7%	14.7% to 29.5%
	Risk-free interest rate	0.02% to 0.8%	0.08% to 0.5%
	Expected life (performance period)	3 years	3 years
Stock Option Activity	The following table represents stock option activity for the three months ended March 31, 2015:
						Weighted-Average
		Number of		Weighted-Average		Remaining
		Stock Options		Exercise Price		Contract Life
	Outstanding at beginning of period	360,376		$	11.29
	Exercised	—		$	—
	Forfeited	—		$	—
	Outstanding at end of period	360,376		$	11.29	1.8
	Exercisable at end of period	360,376		$	11.29	1.8

Derivative_Instruments_and_Hed1

Derivative Instruments and Hedging Activities (Tables)	3 Months Ended
	Mar. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Notional Amounts of Outstanding Derivatives	As of March 31, 2015, the Company had the following outstanding interest rate derivatives that were designated as cash flow hedges:
	Interest Rate Derivative		Number of Instruments		Notional Amount
	Interest Rate Swaps		4		$150.0 million
Fair Value of Derivative Financial Instruments and their Classification on the Balance Sheet	The following table presents the fair value of our derivative financial instruments as well as the classification on the Consolidated Balance Sheets (see Note 12 for additional information regarding the fair value of these derivative instruments):
	Fair Value of Derivative Instruments
		Asset Derivatives
		As of March 31, 2015						As of December 31, 2014
	(In thousands)	Balance Sheet Location		Fair Value				Balance Sheet Location		Fair Value
	Derivatives designated
	as hedging instruments:
	Interest rate swap	Other assets, net		$	575			Other assets, net		$	256
	Fair Value of Derivative Instruments
		Liability Derivatives
		As of March 31, 2015						As of December 31, 2014
	(In thousands)	Balance Sheet Location		Fair Value				Balance Sheet Location		Fair Value
	Derivatives designated
	as hedging instruments:
		Accounts payable and						Accounts payable and
	Interest rate swap	other liabilities		$	1,804			other liabilities		$	1,349
Effect of Derivative Financial Instruments on the Consolidated Statements of Operations and Comprehensive Income	The following table presents the effect of our derivative financial instruments on the Consolidated Statements of Operations and Comprehensive Income:
	The Effect of Derivative Instruments on the Consolidated Statements of Operations and Comprehensive Income
			Location of Gain or
	(In thousands)		(Loss) Recognized		Three Months Ended
	Derivatives in Cash Flow Hedging		in Income		March 31,
	Relationships (Interest Rate Swaps)		on Derivative		2015				2014
	Amount of gain/(loss) recognized in OCI on derivative				$	(476	)		$	(407	)
	Amount of loss reclassified from accumulated
	OCI into interest expense		Interest expense		$	(340	)		$	(344	)
	Amount of gain/(loss) recognized in
	income on derivative (ineffective portion and
	amount excluded from effectiveness testing)		Other expense		$	—			$	—
Offsetting assets and liabilities
	Offsetting of Derivative Assets and Liabilities
													Gross Amounts Not Offset in
											Net Amounts of		the Balance Sheets
			Gross Amounts				Gross Amounts				Assets/Liabilities				Cash
			of Recognized				Offset in the				Presented in the		Financial		Collateral		Net
	(In thousands)		Assets/Liabilities				Balance Sheets				Balance Sheets		Instruments		Received		Amount
	31-Mar-15
	Offsetting Derivative
	Assets		$	575			$	—			$	575	$	—	$	—	$	575
	Liabilities		$	1,804			$	—			$	1,804	$	—	$	—	$	1,804
	31-Dec-14
	Offsetting Derivative
	Assets		$	256			$	—			$	256	$	—	$	—	$	256
	Liabilities		$	1,349			$	—			$	1,349	$	—	$	—	$	1,349

Fair_Value_Tables

Fair Value (Tables)	3 Months Ended
	Mar. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Schedule of Liabilities Measured at Fair Value
				Fair Value at March 31, 2015 Using
				Quoted Prices in
				Active Markets		Significant
				for Identical		Other		Significant
				Assets or		Observable		Unobservable
		Carrying		Liabilities		Inputs		Inputs
	(In thousands)	Value		(Level 1)		(Level 2)		(Level 3)
	Mortgage notes payable	$	282,587	$	—	$	—	$	295,168
	Unsecured debt	$	544,000	$	—	$	561,217	$	—
				Fair Value at December 31, 2014 Using
				Quoted Prices in
				Active Markets		Significant
				for Identical		Other		Significant
				Assets or		Observable		Unobservable
		Carrying		Liabilities		Inputs		Inputs
	(In thousands)	Value		(Level 1)		(Level 2)		(Level 3)
	Mortgage notes payable	$	272,613	$	—	$	—	$	283,728
	Unsecured debt	$	476,500	$	—	$	489,558	$	—

Business_Details

Business (Details)	Mar. 31, 2015
Real Estate Properties [Line Items]
Apartment units owned	13,328
Number of states	8
Desmond's Tower [Member]
Real Estate Properties [Line Items]
Square feet of space	78,800
Wholly Owned Properties [Member]
Real Estate Properties [Line Items]
Number of apartment communities owned	51
Unconsolidated Properties, Managed [Member]
Real Estate Properties [Line Items]
Number of apartment communities owned	2

Acquisition_Development_and_Di2

Acquisition, Development, and Disposition Activity Acquisition, Development, and Disposition Text (Details) (USD $)	3 Months Ended			12 Months Ended
	Mar. 31, 2015		Mar. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Apr. 25, 2014
	Units
	property
Business Acquisition [Line Items]
Apartment units owned	13,328
Costs associated with acquisitions	$62,000		$86,000
Ownership percentage	50.00%			50.00%
Gain on change in control	444,000		0
Interest costs capitalized	1,400,000		1,000,000
Payroll costs capitalized	980,000		770,000
Development costs	199,000		330,000
Costs to date	75,826,000			73,581,000
Maximum exposure	55,084,000
Construction loan	0
Nature of Common Ownership or Management Control Relationships	1
Debt Guarantee	100.00%
Percentage of development costs to date included	100.00%
Investment in unconsolidated entities	55,084,000			54,800,000
Total sales price	16,500,000
Gain on sale of property	9,700,000
Number of properties classified as held for sale	1			0
Sales Commissions and Fees	319,000
Desmond's Tower [Member]
Business Acquisition [Line Items]
Square feet of space	78,800
Bristol Development Group [Member]
Business Acquisition [Line Items]
Noncontrolling interest cash contribution	350,000
Current Development [Member]
Business Acquisition [Line Items]
Apartment units owned	564
Development costs	185,604,000	[1]
Costs to date	156,987,000
Construction loan	59,420,000
Planned development [Member]
Business Acquisition [Line Items]
Apartment units owned	533	[2]
Costs to date	35,371,000
Early Development [Member]
Business Acquisition [Line Items]
Apartment units owned	882
Development costs	409,000,000	[3]
Costs to date	137,800,000
Construction loan	0
Long-term Construction Loan, Current, AEC Portion	0
Investment in unconsolidated entities	55,084,000
Warner Center [Member] | Planned development [Member]
Business Acquisition [Line Items]
Apartment units owned	379	[2]
Ownership percentage	100.00%
Costs to date	18,825,000
Construction loan	0
350 8th [Member] | Current Development [Member]
Business Acquisition [Line Items]
Purchase price	46,600,000
Apartment units owned	410
Ownership percentage	50.01%
Square feet of space	40,000
Maximum exposure	45,570,000
Long-term Construction Loan	0			143,600,000		143,600,000
350 8th [Member] | Planned development [Member]
Business Acquisition [Line Items]
Apartment units owned	410
Ownership percentage	50.01%
Development costs	245,000,000	[3]
Costs to date	97,528,000
Construction loan	0
Long-term Construction Loan, Current, AEC Portion	0	[4]
950 East Third [Member] | Current Development [Member]
Business Acquisition [Line Items]
Apartment units owned	472
Ownership percentage	50.00%
Maximum exposure	9,514,000
950 East Third [Member] | Planned development [Member]
Business Acquisition [Line Items]
Apartment units owned	472
Ownership percentage	50.00%
Development costs	164,000,000	[3]
Costs to date	40,272,000
Construction loan	0
Long-term Construction Loan, Current, AEC Portion	0
5th and Huntington [Member] | Planned development [Member]
Business Acquisition [Line Items]
Apartment units owned	154	[2]
Ownership percentage	100.00%
Costs to date	16,546,000	[5]
Construction loan	0
The Edge at Flagler [Member]
Business Acquisition [Line Items]
Purchase price	80,200,000
Earnest money deposit	4,000,000
Apartment units owned	331
Lease up period	18 months
Termination Fee	8,000,000
1160 Hammond [Member]
Business Acquisition [Line Items]
Purchase price	80,400,000
Apartment units owned	345
Costs associated with acquisitions	57,000			26,000	24,000
5th and Huntington [Member]
Business Acquisition [Line Items]
Ownership percentage	100.00%
5th and Huntington [Member] | Planned development [Member]
Business Acquisition [Line Items]
Purchase price	8,400,000				13,100,000
Apartment units owned	154
350 8th [Member] | Planned development [Member]
Business Acquisition [Line Items]
Purchase price	46,600,000
Apartment units owned	410
Area of land	3.36
7001 Arlington at Bethesda [Member]
Business Acquisition [Line Items]
Square feet of space	6,898
Area of land	2.5
Equity interest	98.10%
7001 Arlington at Bethesda [Member] | Current Development [Member]
Business Acquisition [Line Items]
Apartment units owned	140
Equity interest	98.10%	[6]
Development costs	53,400,000	[1]
Costs to date	49,639,000
Construction loan	23,085,000
Cantabria at Turtle Creek [Member] | Current Development [Member]
Business Acquisition [Line Items]
Apartment units owned	249
Equity interest	100.00%
Development costs	55,904,000	[1]
Costs to date	55,874,000
Construction loan	36,335,000
NorthwoodRavinPortfolio [Member]
Business Acquisition [Line Items]
Number of real estate properties to acquire	7
Purchase price	323,900,000
Mortgage loan assumed	28,000,000
Earnest money deposit	10,000,000
Hampton Point [Member]
Business Acquisition [Line Items]
Total sales price	60,000,000
Gain on sale of property	$41,000,000
[1]	Total capital costs are calculated as if owned 100% by AEC and represent estimated costs for projects under development inclusive of all capitalized costs in accordance with GAAP. Based on current projections as of May 1, 2015.
[2]	Based on current projections as of May 1, 2015.
[3]	Total capital costs are calculated as if owned 100% by AEC and represent estimated costs for projects under development inclusive of all capitalized costs in accordance with GAAP. Based on current projections as of May 1, 201
[4]	AEC has guaranteed 100% of a $143.6 million construction loan which had no outstanding balance as of March 31, 2015.
[5]	Does not include the $444 gain change in control related to the acquisition of our partner's interest.
[6]	Ownership percentage is based on expected total equity of the joint venture and is subject to change based on changes in total equity. Costs are shown at 100%. Joint venture partner contribution is $350.

Acquisition_Development_and_Di3

Acquisition, Development, and Disposition Activity Purchase Price Allocation (Details) (USD $)	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014	Dec. 31, 2014
	Units
Business Acquisition [Line Items]
Apartment units owned	13,328
Development costs	$199,000		$330,000
Land	6,953,000
Buildings and improvements	71,664,000
Furniture and fixtures	1,270,000
Existing leases (Other assets)	463,000
Total	80,350,000
Construction in progress	75,826,000			73,581,000
Construction loan	0
1160 Hammond [Member]
Business Acquisition [Line Items]
Purchase price	80,400,000
Apartment units owned	345
Varela [Member]
Business Acquisition [Line Items]
Purchase price	79,450
Apartment units owned	350
Current Development [Member]
Business Acquisition [Line Items]
Apartment units owned	564
Development costs	185,604,000	[1]
Construction in progress	156,987,000
Construction loan	59,420,000
Current Development [Member] | The Desmond on Wilshire [Member]
Business Acquisition [Line Items]
Apartment units owned	175
Equity interest	100.00%
Development costs	76,300,000	[1]
Construction in progress	51,474,000
Construction loan	0
Future Development [Member]
Business Acquisition [Line Items]
Apartment units owned	533	[2]
Construction in progress	35,371,000
350 8th [Member] | Current Development [Member]
Business Acquisition [Line Items]
Purchase price	46,600,000
Apartment units owned	410
350 8th [Member] | Future Development [Member]
Business Acquisition [Line Items]
Apartment units owned	410
Development costs	245,000,000	[3]
Construction in progress	97,528,000
Construction loan	$0
[1]	Total capital costs are calculated as if owned 100% by AEC and represent estimated costs for projects under development inclusive of all capitalized costs in accordance with GAAP. Based on current projections as of May 1, 2015.
[2]	Based on current projections as of May 1, 2015.
[3]	Total capital costs are calculated as if owned 100% by AEC and represent estimated costs for projects under development inclusive of all capitalized costs in accordance with GAAP. Based on current projections as of May 1, 201

Acquisition_Development_and_Di4

Acquisition, Development, and Disposition Activity Pro Forma (Details) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Actual revenue from acquisitions	$239	$0
Actual net loss from acquisitions	-252	0
Pro forma revenue	48,581	50,306
Pro forma net income applicable to common shares	$420	$42,201
Pro forma earnings per common share - basic:
Pro forma net income applicable to common shares	$0.01	$0.74
Pro forma earnings per common share - diluted:
Pro forma net income applicable to common shares	$0.01	$0.73

Debt_Debt_outstanding_Details

Debt Debt outstanding (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Credit spread	1.40%
All-in rate	2.66%
Secured	$282,587,000	$272,613,000
Unsecured notes	250,000,000	250,000,000
Unsecured term loan	150,000,000	150,000,000
Total debt	826,587,000	749,113,000
Weighted average interest rate	3.50%	3.70%
Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Secured	223,167,000	223,934,000
Secured Debt Weighted Average Interest Rate	4.80%	4.80%
Unsecured notes	250,000,000	250,000,000
Total debt	473,167,000	473,934,000
Weighted average interest rate	4.60%	4.60%
Fixed Rate Debt Unsecured Notes [Member] [Domain]
Debt Instrument [Line Items]
Unsecured Debt Weighted Average Interest Rate	4.40%	4.40%
Variable Rate Debt Hedged [Member]
Debt Instrument [Line Items]
Unsecured term loan		125,000,000
Unsecured Debt Weighted Average Interest Rate		2.70%
Total debt	150,000,000	125,000,000
Weighted average interest rate	2.40%	2.70%
Fixed Rate Debt Hedged - Instrument 2 [Member] [Member]
Debt Instrument [Line Items]
Unsecured term loan	25,000,000	0
Unsecured Debt Weighted Average Interest Rate	1.60%	0.00%
Fixed Rate Debt Hedged [Member]
Debt Instrument [Line Items]
Fixed derivative rate	1.26%
Unsecured term loan	125,000,000
Unsecured Debt Weighted Average Interest Rate	2.70%
Variable Rate Debt Unhedged [Member]
Debt Instrument [Line Items]
Secured	59,420,000	48,679,000
Secured Debt Weighted Average Interest Rate	1.50%	1.50%
Total debt	203,420,000	150,179,000
Weighted average interest rate	1.50%	1.50%
Variable Rate Debt Unhedged Revolver [Member]
Debt Instrument [Line Items]
Unsecured term loan	144,000,000	76,500,000
Unsecured Debt Weighted Average Interest Rate	1.50%	1.50%
Variable Rate Debt Unhedged Term Loan [Member]
Debt Instrument [Line Items]
Unsecured term loan		$25,000,000
Unsecured Debt Weighted Average Interest Rate	0.00%	1.60%
2018 derivative [Member]
Debt Instrument [Line Items]
Fixed derivative rate	1.75%
All-in rate	3.15%
2015 Derivative [Member]
Debt Instrument [Line Items]
Fixed derivative rate	1.42%
All-in rate	2.82%
2013 derivative [Domain]
Debt Instrument [Line Items]
Fixed derivative rate	1.55%
All-in rate	2.95%

Debt_Textual_Details

Debt Textual (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014	Apr. 25, 2014
Debt Instrument [Line Items]
Unsecured term loan	$150,000,000		$150,000,000
Debt term	5 years
Construction loan	0
Cash paid for interest	6,200,000	7,300,000
Variable Rate Debt Hedged [Member]
Debt Instrument [Line Items]
Unsecured term loan			125,000,000
350 8th [Member]
Debt Instrument [Line Items]
Debt Instrument, Description of Variable Rate Basis	160.00%
Current Development [Member]
Debt Instrument [Line Items]
Construction loan	59,420,000
Current Development [Member] | 350 8th [Member]
Debt Instrument [Line Items]
Long-term Construction Loan	$0		$143,600,000	$143,600,000
Debt term	5 years

Goodwill_and_Other_Intangible_1

Goodwill and Other Intangible Assets Intangible (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill	1.3
Residential Real Estate [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization period	12 months
Desmond's Tower [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization period	60 months
1160 Hammond [Member] | Residential Real Estate [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization period	6 months

Investment_in_Unconsolidated_E2

Investment in Unconsolidated Entities (Details) (USD $)	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014	Dec. 31, 2014	Apr. 25, 2014	Feb. 03, 2014
	Units
Schedule of Equity Method Investments [Line Items]
Outside basis	$1,780,000
Apartment units owned	882
Debt term	5 years
Construction loan	0
Partner contribution	74,300,000
Management fees revenue	315,000		87,000
Current Development [Member]
Schedule of Equity Method Investments [Line Items]
Apartment units owned	564
Construction loan	59,420,000
Management fees revenue	835,000
Current Development [Member] | 350 8th [Member]
Schedule of Equity Method Investments [Line Items]
Outside basis	1,250,000
Apartment units owned	410
Square feet of space	40,000
Purchase price	46,600,000
Carrying value of partnership						50,300,000
Debt term	5 years
Long-term Construction Loan	0			143,600,000	143,600,000
Partner contribution	44,300,000
Management fees revenue	460,000
Current Development [Member] | 950 East Third [Member]
Schedule of Equity Method Investments [Line Items]
Outside basis	530,000
Apartment units owned	472
Contribution of land value	30,000,000	[1]
Management fees revenue	$375,000
[1]	Land valued at $30.0 million was contributed by our partner, Legendary Investors Group No. 1 LLC ("Legendary"), to the partnership.

Noncontrolling_Interests_Nonco

Noncontrolling Interests Noncontrolling Interests Textual (Details) (USD $)	3 Months Ended
	Mar. 31, 2015
Bristol Development Group [Member]
Noncontrolling Interest [Line Items]
Noncontrolling interest cash contribution	$350,000
7001 Arlington at Bethesda [Member]
Noncontrolling Interest [Line Items]
Equity interest	98.10%
Area of land	2.5
Contribution	$12,200,000
Real estate units intended to develop	140
Square feet of space	6,898

Equity_Equity_Details

Equity Equity (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Equity Note [Line Items]
Balance, December 31, 2014		$647,576
Balance, March 31, 2015	637,266	647,576
Common Stock [Member]
Equity Note [Line Items]
Balance, December 31, 2014	5,771
Issuance of common shares	22
Balance, March 31, 2015	5,793
Additional Paid-in Capital [Member]
Equity Note [Line Items]
Balance, December 31, 2014	758,079
Share-based compensation	1,447
Balance, March 31, 2015	759,526
Accumulated Distributions in Excess of Net Income [Member]
Equity Note [Line Items]
Balance, December 31, 2014	-114,551
Net income applicable to AERC	744
Common share dividends declared	-12,277
Balance, March 31, 2015	-126,084
Accumulated Other Comprehensive Income (Loss) [Member]
Equity Note [Line Items]
Balance, December 31, 2014	-1,093
Changes in fair value of hedge instruments	-136
Balance, March 31, 2015	-1,229
Treasury Stock [Member]
Equity Note [Line Items]
Balance, December 31, 2014	980
Share-based compensation	1,055
Purchase of common shares	-1,165
Balance, March 31, 2015	1,090
Noncontrolling Interest [Member]
Equity Note [Line Items]
Balance, December 31, 2014		350
Balance, March 31, 2015	$350	$350

Earnings_Per_Share_Earnings_pe

Earnings Per Share Earnings per share table (Details) (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014
Numerator - basic and diluted:
Net income	$744		$42,273
Allocation to participating securities	0		157
Net income applicable to common shares	744		42,116
Denominator - basic:	57,612,000		57,362,000
Effect of dilutive securities	613,000	[1]	471,000	[1]
Denominator - diluted:	58,225,000		57,833,000
Earnings per common share - basic:
Net income applicable to common shares - basic	$0.01		$0.73
Earnings per common share - diluted:
Net income applicable to common shares - diluted	$0.01		$0.73
Antidilutive shares			42
Income from continuing operations [Member]
Numerator - basic and diluted:
Allocation to participating securities	$0		$157
[1]	The Company has excluded 42 stock options for the three months ended March 31, 2014 as their inclusion would be anti-dilutive.

Equity_Based_Award_Plans_Equit

Equity Based Award Plans Equity Based Award Plans Textual (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Sep. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation	$1,300,000
Share-based compensation in capitalized payroll	300,000	100,000
Stock options awarded	0	0
Options exercised	0	0
Intrinsic value of stock options	4,800,000		2,600,000
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-Average grant date fair value	$24.27
Fair value of restricted shares vested	174,000	90,000
Unrecognized compensation costs	6,100,000
Weighted average period of unrecognized compensation cost	2 years 2 months
Restricted Share and RSU's [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-Average grant date fair value		$16
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-Average grant date fair value	$24.71
Fair value of restricted shares vested	3,300,000	2,500,000
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Estimated grant-date fair value	$90,000	$4,300,000

Equity_Based_Award_Plans_Restr

Equity Based Award Plans Restricted Shares (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2015
Restricted Share and RSU's [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-Average grant date fair value	$16
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Nonvested at beginning of period		702,860
Nonvested at beginning of period weighted average grant date fair value		$10.31
Granted		100,618
Weighted-Average grant date fair value		$24.71
Vested		134,378
Vested weighted average grant date fair value		$18.32
Forfeited		10,021
Forfeited weighted average grant date fair value		$10.73
Nonvested at end of period		659,079
Nonvested at end of period weighted average grant date fair value		$10.87
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Nonvested at beginning of period		45,365
Nonvested at beginning of period weighted average grant date fair value		$17.06
Granted		13,249
Weighted-Average grant date fair value		$24.27
Vested		7,235
Vested weighted average grant date fair value		$20.17
Forfeited		1,192
Forfeited weighted average grant date fair value		$17.46
Nonvested at end of period		50,187
Nonvested at end of period weighted average grant date fair value		$18.51

Equity_Based_Award_Plans_Monte

Equity Based Award Plans Monte Carlo (Details) (Restricted Stock [Member])	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk free rate minimum		0.02%	0.08%
Risk free rate maximum		0.80%	0.50%
Expected life of options (in years)	3 years	3 years
AERC [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility minimum		22.30%	18.10%
Expected volatility maximum		24.20%	22.50%
Peer Group [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility minimum		16.90%	14.70%
Expected volatility maximum		24.70%	29.50%

Equity_Based_Award_Plans_Stock

Equity Based Award Plans Stock Options (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Outstanding at the beginning of period	360,376
Exercised	0	0
Forfeited	0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested Options Forfeited, Number of Shares	0	5,000
Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price	$0
Outstanding at the end of the period	360,376
Forfeited	$0
Exercisable at the end of the period	360,376
Weighted average exercise price outstanding at the end of the period	$11.29		$11.29
Weighted-Average exercise price exercisable at the end of the period	$11.29
Weighted-Average remaining contract life outstanding at the end of the period	1 year 10 months
Weighted-Average remaining contract life exercisable at the end of the period	1 year 10 months

Derivative_Instruments_and_Hed2

Derivative Instruments and Hedging Activities Derivative Instruments and Hedging Activities Textual (Details) (USD $)	3 Months Ended
	Mar. 31, 2015
Derivative [Line Items]
Inception date	19-Dec-11
Effective date	7-Jun-13
Amount of cash flow hedge	$150,000,000
Term Loan, Amount Outstanding	150,000,000
Credit spread	1.40%
All-in rate	2.66%
Lower range of basis spread	0.90%
Higher range of basis spread	1.90%
Fair value of the derivative in a net liability position	1,900,000
Fair value of assets needed for immediate settlement	1,900,000
Derivative interest payable	87,000
Amount of other comprehensive income to be reclassified to earnings over the next twelve months	1,200,000
2015 Derivative [Member]
Derivative [Line Items]
Fixed derivative rate	1.42%
All-in rate	2.82%
2018 derivative [Member]
Derivative [Line Items]
Fixed derivative rate	1.75%
All-in rate	3.15%
Fixed Rate Debt Hedged [Member]
Derivative [Line Items]
Fixed derivative rate	1.26%
2013 derivative [Domain]
Derivative [Line Items]
Inception date	2-Apr-13
Effective date	2-Jun-16
Amount of cash flow hedge	$125,000,000
Fixed derivative rate	1.55%
All-in rate	2.95%

Derivative_Instruments_and_Hed3

Derivative Instruments and Hedging Activities Outstanding Interest Rate Derivatives (Details) (USD $)	Mar. 31, 2015
In Millions, unless otherwise specified
Derivative [Line Items]
Derivative, Number of Instruments Held	4
Amount of cash flow hedge	$150

Derivative_Instruments_and_Hed4

Derivative Instruments and Hedging Activities Fair Value of Derivative Instruments and their Classification on the Balance Sheet (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Derivatives, Fair Value [Line Items]
Other assets	$575	$256
Other liabilities	$1,804	$1,349

Derivative_Instruments_and_Hed5

Derivative Instruments and Hedging Activities Effect of Derivative Financial Instruments on the Statements of Income and Comprehensive Income (Details) (Designated as Hedging Instrument [Member], Interest Rate Swap [Member], USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain/(loss) recognized in OCI on derivative	($476)	($407)
Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of loss reclassified from accumulated OCI into interest expense	-340	-344
Other Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain/(loss) recognized in income on derivative (ineffective portion and amount excluded from effectiveness testing)	$0	$0

Derivative_Instruments_and_Hed6

Derivative Instruments and Hedging Activities Offsetting financial assets and liabilities (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Offseting Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset	$575	$256
Derivative Assets	575	256
Derivative Liability, Fair Value, Gross Liability	1,804	1,349
Derivative Liabilities	$1,804	$1,349

Fair_Value_Fair_Value_Details

Fair Value Fair Value (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage notes payable	$282,587,000	$272,613,000
Unsecured debt	544,000,000	476,500,000
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage notes payable	0	0
Unsecured debt	0	0
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage notes payable	0	0
Unsecured debt	561,217,000	489,558,000
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage notes payable	295,168,000	283,728,000
Unsecured debt	$0	$0
Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loan to value ratios	41.00%
Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loan to value ratios	52.00%

Contingencies_Details

Contingencies (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014	Apr. 25, 2014
Loss Contingencies [Line Items]
Intangible assets	$794,000
Cure payment	630,000
Ownership percentage	50.00%	50.00%
Debt term	5 years
350 8th [Member] | Current Development [Member]
Loss Contingencies [Line Items]
Ownership percentage	50.01%
Long-term Construction Loan	$0	$143,600,000	$143,600,000
Debt term	5 years
350 8th [Member] | Future Development [Member]
Loss Contingencies [Line Items]
Ownership percentage	50.01%

Subsequent_Events_Subsequent_E

Subsequent Events Subsequent Events (Details) (USD $)	3 Months Ended
In Millions, except Per Share data, unless otherwise specified	Mar. 31, 2015
Subsequent Event [Line Items]
Disposal Date	6-Apr-15
Total sales price	$16.50
Gain on sale of property	9.7
Dividends payment date	1-May-15
Dividends	$0.21
Dividends record date	15-Apr-15
Dividend declared	6-Mar-15
Merger Agreement Date	22-Apr-15
Per share merger consideration	$28.75
merger agreement termination fee	60
merger agreement transaction expenses	$20