Associated Estates Realty 10-K 18 Feb 15 2014 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information Document (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Feb. 03, 2015	Jun. 30, 2014
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-K
Document Period End Date	31-Dec-14
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Amendment Flag	FALSE
Entity Common Stock, Shares Outstanding		57,715,771
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$997

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Real estate assets
Land	$261,777	$298,441
Building and improvements	1,346,870	1,370,560
Furniture and fixtures	41,609	39,725
Construction in progress	73,581	42,793
Gross real estate	1,723,837	1,751,519
Less: accumulated depreciation	-397,210	-386,841
Net real estate owned	1,326,627	1,364,678
Investment in unconsolidated entities	54,800	9,321
Total net real estate	1,381,427	1,373,999
Cash and cash equivalents	4,692	4,586
Restricted cash	46,361	3,465
Accounts receivable, net
Rents	1,093	1,230
Other	2,977	1,258
Other assets, net	29,147	37,959
Total assets	1,465,697	1,422,497
Liabilities and Equity
Mortgage notes payable	272,613	279,474
Unsecured notes	250,000	250,000
Unsecured revolving credit facility	76,500	133,500
Unsecured term loan	150,000	150,000
Total debt	749,113	812,974
Accounts payable and other liabilities	47,070	42,882
Dividends payable	12,886	12,178
Resident security deposits	3,860	4,112
Accrued interest	5,192	5,551
Total liabilities	818,121	877,697
Equity
Common shares, without par value, $.10 stated value; 91,000,000 authorized; 57,708,675 issued and 57,649,609 outstanding at December 31, 2014 and 57,595,479 issued and 57,476,192 outstanding at December 31, 2013, respectively	5,771	5,760
Paid-in capital	758,079	754,582
Accumulated distributions in excess of accumulated net income	-114,551	-213,275
Accumulated other comprehensive loss	-1,093	-702
Less: Treasury shares, at cost, 56,066 and 119,287 shares at December 31, 2014 and December 31, 2013, respectively	-980	-1,915
Total shareholders' equity attributable to AERC	647,226	544,450
Noncontrolling interest	350	350
Total equity	647,576	544,800
Total liabilities and equity	$1,465,697	$1,422,497

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parentheticals) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]
Common Stock, Stated Value	$0.10	$0.10
Common Stock, Shares Authorized	91,000,000	91,000,000
Common Stock, Shares Issued	57,708,675	57,595,479
Common Stock, Shares Outstanding	57,649,609	57,476,192
Treasury Stock, Shares	56,066	119,287

Consolidated_Statements_of_Ope

Consolidated Statements of Operations and Comprehensive Income (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
REVENUE
Property revenue	$191,306	$179,982	$157,507
Office revenue	1,883	1,497	1,046
Property management and construction services revenue	891	0	0
Total revenue	194,080	181,479	158,553
EXPENSES
Property operating and maintenance	73,001	67,879	60,628
Depreciation and amortization	63,557	58,053	49,938
General and administrative	18,729	19,481	16,995
Development costs	779	912	864
Construction services	396	0	176
Costs associated with acquisitions	185	524	798
Total expenses	156,647	146,849	129,399
Operating income	37,433	34,630	29,154
Interest expense	-25,976	-29,342	-29,273
Gain on disposition of properties	133,254	0	0
Income (loss) from continuing operations	144,711	5,288	-119
Income from discontinued operations:
Operating income, net of interest expense	0	3,179	3,881
Gain on disposition of properties	0	52,828	26,849
Income from discontinued operations	0	56,007	30,730
Net income	144,711	61,295	30,611
Net income attributable to noncontrolling interests	0	-45	-19
Net income attributable to AERC	144,711	61,250	30,592
Allocation to participating securities	473	228	0
Net income applicable to common shares	144,238	61,022	30,592
Earnings per common share - basic:
Income from continuing operations applicable to common shares	$2.51	$0.10	$0
Income from discontinued operations	$0	$1.08	$0.66
Net income applicable to common shares	$2.51	$1.18	$0.66
Earnings per common share - diluted:
Income from continuing operations applicable to common shares	$2.49	$0.10	$0
Income from discontinued operations	$0	$1.07	$0.66
Net income applicable to common shares	$2.49	$1.17	$0.66
Comprehensive income:
Net income	144,711	61,295	30,611
Other comprehensive income:
Change in fair value and reclassification of hedge intstruments	-391	2,232	-2,529
Total comprehensive income	144,320	63,527	28,082
Comprehensive loss attributable to noncontrolling interests	0	-45	-19
Total comprehensive income attributable to AERC	$144,320	$63,482	$28,063
Weighted average shares outstanding - basic	57,478	51,622	46,063
Weighted average shares outstanding - diluted	57,975	52,184	46,063

Consolidated_Statements_of_Sha

Consolidated Statements of Shareholders' Equity (USD $)	Total	Common Stock	Additional Paid-in Capital	Accumulated Distributions in Excess of Net Income	Accumulated Other Comprehensive Loss	Treasury Stock	Noncontrolling Interest
In Thousands, except Share data, unless otherwise specified
Balance at Dec. 31, 2011	$309,822	$4,657	$583,172	($228,545)	($405)	($50,086)	$1,029
Balance (in shares) at Dec. 31, 2011		42,330,899
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to AERC	30,592			30,592
Other comprehensive income:
Change in fair value of hedge intstruments	-2,529				-2,529
Noncontrolling interest cash contribution	350						350
Noncontrolling interest	-35						-35
Redemption of operating partnership units	0
Share-based compensation	4,297		2,379	2		1,916
Purchase of common shares (in shares)		-59,458
Purchase of common shares	-959					-959
Issuance of common shares (in shares)		7,066,166
Issuance of common shares	98,149	296	48,763			49,090
Option exercises (in shares)		35,000
Option exercises	312		273			39
Restricted share activity, net		154,032
Cash dividends declared and paid to common shareholders	-35,257			-35,257
Dividends	$0.71
Balance at Dec. 31, 2012	404,742	4,953	634,587	-233,208	-2,934	0	1,344
Balance (in shares) at Dec. 31, 2012		49,526,639
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to AERC	61,250			61,250
Other comprehensive income:
Change in fair value of hedge intstruments	2,232				2,232
Noncontrolling interest cash contribution	-4,541						-994
Noncontrolling interest	355
Redemption of operating partnership units	1,734		355
Purchase of noncontrolling interests	-3		3,547
Share-based compensation	5,478	70	5,406	2		0
Purchase of common shares (in shares)		-162,399
Purchase of common shares	-2,618					-2,618
Issuance of common shares (in shares)	2,921,667
Issuance of common shares (in shares)	3,403,333	7,176,107
Issuance of common shares	116,751	716	116,029			6
Option exercises (in shares)		259,164
Option exercises	2,470	21	1,752			697
Restricted share activity, net		676,681
Cash dividends declared and paid to common shareholders	-41,319			-41,319
Dividends	$0.76
Balance at Dec. 31, 2013	544,800	5,760	754,582	-213,275	-702	-1,915	350
Balance (in shares) at Dec. 31, 2013		57,476,192
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to AERC	144,711			144,711
Other comprehensive income:
Change in fair value of hedge intstruments	-391				-391
Share-based compensation	4,742		2,772	1		1,969
Purchase of common shares (in shares)		-64,672
Purchase of common shares	-1,034					-1,034
Issuance of common shares (in shares)		4,738
Issuance of common shares	0	0	0
Option exercises (in shares)	80,930	80,930
Option exercises	733	8	725
Restricted share activity, net		152,421
Cash dividends declared and paid to common shareholders	-45,988			-45,988
Dividends	$0.79
Balance at Dec. 31, 2014	$647,576	$5,771	$758,079	($114,551)	($1,093)	($980)	$350
Balance (in shares) at Dec. 31, 2014		57,649,609

Consolidated_Statements_of_Sha1

Consolidated Statements of Shareholders' Equity (Parenthetical) (Parentheticals) (USD $)	0 Months Ended												12 Months Ended
	Nov. 03, 2014	Aug. 01, 2014	1-May-14	Feb. 03, 2014	Nov. 01, 2013	Aug. 01, 2013	1-May-13	Feb. 01, 2013	Nov. 01, 2012	Aug. 01, 2012	1-May-12	Feb. 01, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Stockholders' Equity (Parenthetical) [Abstract]
Dividends	$0.20	$0.19	$0.19	$0.19	$0.19	$0.19	$0.19	$0.19	$0.18	$0.18	$0.18	$0.17	$0.79	$0.76	$0.71

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash flow from operating activities:
Net income	$144,711	$61,295	$30,611
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	63,557	59,832	55,544
Gain on disposition of properties	-133,254	-52,828	-26,849
Amortization of deferred financing costs and other	1,088	1,178	2,168
Share-based compensation expense	3,839	4,611	4,055
Net change in assets and liabilities:
Accounts receivable	-458	-879	3,806
Accounts payable and accrued expenses	-1,823	4,995	1,197
Other operating assets and liabilities	-1,428	3,621	74
Total adjustments	-68,479	20,530	39,995
Net cash flow provided by operating activities	76,232	81,825	70,606
Cash flow from investing activities:
Recurring fixed asset additions	-9,349	-11,710	-10,659
Revenue enhancing/non-recurring fixed asset additions	-4,445	-1,916	-1,655
Acquisition fixed asset additions	-49,506	-234,652	-159,506
Development fixed asset additions	-79,668	-85,356	-47,701
Net proceeds from disposition of operating properties	212,053	135,580	64,422
Contributions to joint ventures	-20,811	-9,271	0
Deposits on potential future acquisitions	3,192	-13,192	-4,500
Cash proceeds from sale of equity interest in development property	24,075	0	0
Escrow deposits related to property sales	-115,587	0	0
Escrow deposit disbursements related to property acquisition	72,292	0	0
Costs paid on behalf of joint venture	-6,006	0	0
Reimbursements of costs paid on behalf of joint venture	5,996	0	0
Other investing activity	579	1,079	2,280
Net cash flow provided by (used for) investing activities	32,815	-219,438	-157,319
Cash flow from financing activities:
Principal amortization payments on mortgage notes payable	-2,135	-2,785	-3,058
Principal repayments of mortgage notes payable	-44,538	-129,319	-178,239
Payment of debt procurement costs	-927	-3,952	-3,546
Proceeds from secured construction loans	40,579	8,100	0
Proceeds from secured mortgages	0	0	48,513
Proceeds from issuance of unsecured notes	0	250,000	0
Proceeds from term loan borrowings	0	0	25,000
Unsecured revolving credit facility borrowings	234,000	557,200	522,300
Unsecured revolving credit facility repayments	-291,000	-614,200	-389,800
Common share dividends paid	-44,849	-38,933	-32,406
Operating partnership distributions paid	0	-42	-54
Operating partnership redemption	0	-1,393	0
Exercise of stock options	733	2,470	312
Issuance of common shares	0	116,751	98,149
Purchase of treasury shares	-1,034	-2,618	-959
Noncontrolling interest investment in partnership	0	0	350
Purchase of noncontrolling interest in partnership	0	-4,544	0
Other financial activities, net	230	724	563
Net cash flow (used for) provided by financing activities	-108,941	137,459	87,125
Increase (decrease) in cash and cash equivalents	106	-154	412
Cash and cash equivalents, beginning of period	4,586	4,740	4,328
Cash and cash equivalents, end of period	$4,692	$4,586	$4,740

Business

Business	12 Months Ended
	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
BUSINESS	BUSINESS
	Associated Estates Realty Corporation and its consolidated subsidiaries (the "Company") is a fully-integrated, self-administered and self-managed equity real estate investment trust ("REIT") specializing in multifamily ownership, operation, acquisition, development, construction, disposition and property management activities. Unless the context otherwise requires, the terms "we," "us," and "our" refer to Associated Estates Realty Corporation and its consolidated subsidiaries. Our primary source of income is rental revenue. Additional income is derived from property management and construction services revenue. We own a taxable REIT subsidiary that performs construction services for our own account in connection with the development of multifamily properties that we own and operate, including consolidated and unconsolidated joint ventures. As of December 31, 2014, our operating portfolio consisted of 49 apartment communities containing 12,734 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 three apartment communities that we expect to acquire pursuant to existing contracts. Any reference to the number of units, square footage and total estimated capital cost in the financial statement footnotes are unaudited.

Significant_Accounting_Policie

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
SIGNIFICANT ACCOUNTING POLICIES	SIGNIFICANT ACCOUNTING POLICIES
	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.
	The accompanying consolidated financial statements include the accounts of all subsidiaries, any REIT subsidiaries (which are taxed as Taxable REIT Subsidiaries ("TRS") under the REIT Modernization Act implemented in 1999) and a partnership in which we were a 98.1% and 97.0% partner at December 31, 2014 and 2013, respectively, that owns a property in Bethesda, Maryland.
	Limited partnership interests held by others in the partnership in which we are a 98.1% and 97.0% partner at December 31, 2014 and 2013, respectively, are reflected as "Noncontrolling interest" in the Consolidated Balance Sheets. Capital contributions, distributions and profits and losses are allocated to noncontrolling interests in accordance with the terms of the partnership agreements, respectively. All significant intercompany balances and transactions have been eliminated in consolidation.
	We own 100% of the common stock of all taxable REIT subsidiaries included in our consolidated financial statements.
	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.
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	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 twelve months ended December 31, 2014, substantially all of our consolidated revenue was provided by our multifamily properties. We have determined that as of December 31, 2014, we have one reportable segment which is multifamily properties.
	Use of Estimates
	The preparation of the consolidated financial statements in accordance with accounting principles generally accepted in the United States of America ("GAAP") requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the consolidated financial statements and reported amounts of revenues and expenses during the reporting periods. Actual results could differ from these estimates.
	Cash Equivalents
	Highly liquid investments with an original maturity of three months or less when purchased are considered to be cash equivalents.
	Real Estate Capitalization Policies and Depreciation
	Real estate assets are stated at cost less accumulated depreciation. Depreciation is provided on a straight-line basis over the estimated useful lives of the assets as follows:
	Buildings and improvements	5 - 30 years
	Furniture, fixtures and equipment	5 - 10 years
	We capitalize replacements and improvements, such as HVAC equipment, structural replacements, windows, appliances, flooring, carpeting and kitchen/bath replacements and renovations. Ordinary repairs and maintenance, such as unit cleaning, painting and appliance repairs, are expensed when incurred.
	We allocate the purchase price of acquired properties to net tangible and identified intangible assets acquired based on their fair values. In making estimates of fair values for purposes of allocating purchase price, we utilize a number of sources, including analysis provided by an advisor, independent appraisals that may be obtained in connection with the acquisition or financing of the respective property, our analysis of recently acquired and existing comparable properties in our portfolio and other market data. The intangible assets are amortized over the remaining lease terms, which is 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. Transaction costs associated with the acquisition of operating properties are expensed as incurred in "Costs associated with acquisitions."
	Pre-development costs incurred in pursuing future development which is not yet considered probable are expensed as incurred. While what is deemed to be probable can vary from project to project, some examples include the point in time in which a letter of intent has been issued or accepted, the commencement of due diligence or obtainment of approval from the Board of Directors, when necessary. In addition, if a development project becomes no longer probable, any capitalized pre-development costs are written off to expense in "General and administrative."
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	For properties under development, we capitalize interest costs on funds used in construction, real estate taxes and insurance from the commencement of development activity, where we are undergoing activities necessary to get the property ready for its intended use and expenditures for the asset have been made, through the time the property is substantially complete and ready for leasing (i.e., certificate of occupancy has been obtained). For properties under development accounted for under the equity method, we capitalize interest costs on our investment from the commencement of development activity through the time the venture is substantially complete and commenced planned principal operations. We also capitalize internal costs related to our consolidated and equity method ventures, which are primarily payroll, but may also include costs such as travel, lodging and temporary construction facilities that are directly attributable to the construction of a property or asset.
	Certain costs associated with the lease-up of development projects, such as signs and "grand openings" are capitalized and amortized over the estimated life of average tenant relationships, which are approximately 12 months. All other internal costs associated with the lease up of development properties are expensed as incurred. Revenue from incidental operations for properties under development is recognized as a reduction of capitalized project costs. Development assets are fully transfered from construction in progress to fixed assets in the period in which substantially all units have come on-line and are held available for occupancy.
	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, as defined above. Total capitalized interest during 2014, 2013 and 2012 was $4.8 million, $3.6 million and $1.5 million, respectively. Total capitalized payroll costs during 2014, 2013 and 2012 were $3.5 million, $2.8 million and $2.4 million, respectively.
	Classification of Fixed Asset Additions
	We define recurring fixed asset additions to a property as capital expenditures made to replace worn out assets to maintain the property's value. Revenue enhancing/non-recurring fixed asset additions are defined as capital expenditures that increase the value of the property and enable us to increase rents. Acquisition/development fixed asset additions are defined as capital expenditures for the purchase or construction of new properties to be added to our portfolio, or fixed asset additions identified at the time of purchase that are not made until subsequent periods.
	Development Costs Reported on the Consolidated Statements of Operations and Comprehensive Income
	Development costs represent costs incurred related to our in-house development and construction division that do not quality for capitalization and are expensed as incurred.
	Disposition of Real Estate and Investments in Unconsolidated Entities
	Sales of real estate include the sale of land, operating properties and investments in unconsolidated entities which are in-substance real estate. We follow Accounting Standards Codification No. 360-20, Property, Plant and Equipment - Real Estate Sales, in determining whether our sales of real estate meet the criteria for full profit accrual method. The results of operations and gains related to the sale of operating properties for the year ended December 31, 2014 are reported in income from continuing operations in the accompanying Consolidated Statements of Operations and Comprehensive Income. Prior to adoption of ASU 2014-08, and in all prior periods presented, these results were reported in "Income from discontinued operations," in the accompanying Consolidated Statements of Operations and Comprehensive Income. Furthermore, the results of properties classified as held for sale are now reported in income from continuing operations.
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	Impairment of Long-Lived Assets, Development and Investments in Unconsolidated Entities
	Our held for investment real estate assets are assessed for impairment if current events or circumstances, such as significant adverse changes in general market conditions, decreases in property net operating income, or reductions in expected future cash flows, indicate that the carrying value (cost less accumulated depreciation) may not be recoverable. Factors we consider in evaluating impairment of real estate assets held for investment include estimated future growth rates, capitalization rates, occupancy assumptions, current expectations regarding the holding period for the individual assets and external data to the extent available. Real estate assets held for investment are not considered impaired if the undiscounted, estimated future cash flows of the asset (both the annual estimated cash flow from future operations and the estimated cash flow from the theoretical sale of the asset) over its estimated holding period are in excess of the asset's net book value at the measurement date. If the carrying value of any real estate asset held for investment is not recoverable, an impairment loss is recorded to reduce the carrying value of the asset to its fair value. Our development properties are assessed for impairment as well, in which we consider the projected future cash flows from the development properties' planned use upon project completion in relation to their current carrying value plus the projected costs to complete. Our investments in unconsolidated entities are assessed for other than temporary impairment, in which we consider the fair value of the investment in relation to its current carrying value. No impairments were recorded for the years ended December 31, 2014, 2013 and 2012.
	Real Estate Held for Sale
	We periodically classify real estate assets as held for sale. We consider real estate assets to be held for sale when a sales contract is executed with no substantive contingencies in place, inclusive of the completion of the prospective buyer's due diligence period. Assets that are classified as held for sale are recorded at the lower of their carrying amount or fair value less cost to sell. Upon the classification of a real estate asset as held for sale, we estimate its fair value less costs to sell. If the fair value less costs to sell is less than the carrying value, then we reduce the carrying value to the fair value less costs to sell. Subsequent to the classification of assets as held for sale, no further depreciation expense is recorded. There were no properties recorded as held for sale at December 31, 2014 and 2013.
	Income Taxes
	We have elected to be taxed as a REIT under the Internal Revenue Code of 1986 (the "Code"), as amended. As a REIT, we are entitled to a tax deduction for dividends paid to shareholders, thereby effectively subjecting the distributed net income to taxation at the shareholder level only, provided we distribute at least 90.0% of our taxable income and meet certain other qualifications. Our two REIT subsidiaries that have historically engaged in third party property and asset management and third party construction services, respectively, have elected to be treated as Taxable REIT Subsidiaries ("TRS") and operate as C-corporations under the Code. Accordingly, these TRS entities separately account for income taxes. Taxes are recorded for these two TRS subsidiaries to the extent they recognize net profits for both financial statement and income tax purposes. See Note 10 for further details.
	Accounts Receivable
	We make estimates of the amounts we believe will not be collected related to rents receivable. We analyze the accounts receivable aging balance using historical patterns and apply a reserve percentage based upon those historical patterns and current trends at the properties. At December 31, 2014 and 2013, rents receivable, net of a provision for uncollectible amounts of $69,000 and $78,000, respectively, aggregated $1.1 million and $1.2 million, respectively. Other accounts receivable are reviewed and reserved for on a case-by-case basis depending on the nature of the receivable and any current information related to the collectibility of the receivable.
	Deferred Financing Costs
	Costs incurred in obtaining long-term financing, included in "Other assets, net," are deferred and amortized over the life of the associated instrument using the effective interest method.
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	Goodwill
	Goodwill, included in "Other assets, net," is tested for impairment annually, or more frequently if events or changes in circumstances indicate that the carrying value may not be recoverable. See Note 5 for additional information related to intangible assets and goodwill.
	Property Revenue Recognition
	Our residential property leases are for terms of generally one year or less. Rental income is recognized on a straight-line basis over the term of the lease.
	Rent concessions, including any free rent incurred in connection with residential property leases, are amortized on a straight-line basis over the terms of the related leases (approximately one year) and are charged as a reduction of rental revenue.
	Property Management and Construction Services Revenue Recognition
	Property management fees are recognized when the related services are performed and the earnings process is complete. Construction services fees are recognized in accordance with the associated development agreements. See Note 6 for further detail related to construction service fees recognized to date.
	Advertising Costs
	We recognize advertising costs as expense when incurred. The total amount charged to advertising expense for the years ended December 31, 2014, 2013 and 2012, were $2.2 million, $2.0 million and $2.0 million, respectively.
	Share-Based Compensation
	We account for share based compensation using the fair value method to recognize compensation cost. See Note 17 for information about share-based compensation and our equity based award plans.
	Noncontrolling Redeemable Interest
	In 1998, in conjunction with the acquisition of an operating partnership that owned two apartment communities, one of which was sold in October 2005, we issued a total of 522,032 operating partnership units ("OP units"). Holders of OP units were entitled to receive cumulative distributions per OP unit equal to the per share distributions on our common shares. When the OP units were presented for redemption, we were obligated to redeem those OP units for either common shares exchangeable on a one-for-one basis, or the cash equivalent amount, determined as the average closing price for our common shares over the 20-day period preceding the redemption, at our option. During 2013, all remaining OP units were canceled by means of a merger, and thus there are no OP units remaining as of December 31, 2013.
	Noncontrolling Interest
	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 variable interest entity 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 meets the criteria to be classified as a component of permanent equity.
	Index
	On September 24, 2010, we entered into a partnership agreement with Bristol Development Group, an unrelated third-party, for the development of Vista Germantown, a 242-unit apartment community located in downtown Nashville, Tennessee. We contributed $9.4 million to the partnership and held a 90.0% equity interest in the partnership. In February 2013, we funded the redemption of the interest of the minority 10.0% partner of this partnership for $4.5 million, and therefore owned a 100% interest in Vista Germantown as of February 2013. On April 2, 2014, we disposed of Vista Germantown for a sales price of $53.3 million.
	Investment in Unconsolidated Entities
	During the quarter ended March 31, 2014, we entered into a partnership agreement with AIG, an unrelated third-party, for the development and operation of 350 8th, a 410-unit apartment community with 40,000 square feet 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. As of December 31, 2013, this land was included in our consolidated financial statements. Upon the formation of our partnership with AIG, the land and improvements to date, with a carrying value of $50.3 million, were deconsolidated. We are a 50.01% partner in this partnership.
	During the quarter ended September 30, 2013, we entered into a partnership agreement with LPC MM Monrovia, LLC ("Lincoln"), an unrelated third-party, for the limited purpose of acquiring a property in Monrovia, California, and to produce construction drawings for improvements to the property, known as 5th and Huntington. The land, upon which the partnership plans to develop a 154-unit multifamily apartment community, was purchased by the partnership on August 9, 2013 for $13.1 million. We are a 50.0% partner with Lincoln. On February 3, 2015 we purchased Lincoln's 50.0% interest in the partnership for $8.4 million, increasing our ownership percentage in the development to 100%. See Note 19 for further information related to this subsequent event.
	During the quarter ended June 30, 2013, we entered into a partnership agreement with Legendary Investors Group No. 1 LLC ("Legendary"), an unrelated third-party for the development and operation of 950 East Third, a 472-unit apartment community with 19,700 square feet of commercial space located in Los Angeles, California. We are a 50.0% partner with Legendary, who contributed the land at a value of $30.0 million to the joint venture.
As these partnerships are not sufficiently funded to finance the activities of the entities, and not all of the capital will be funded up front, these partnerships are not deemed to have sufficient equity and have therefore been determined to be variable interest entities. It has also been determined that we do not control the decisions that most significantly affect the economics of the entities, and that we do not hold a controlling financial interest in the entities. As such, our investments in the entities are included in our consolidated financial statements using the equity method. To the extent that our cost basis is different from the basis reflected at the unconsolidated entity level, the basis difference is amortized over the life of the related assets.
Derivative Instruments and Hedging Activities
We utilize interest rate swaps to add stability to interest expense and to manage our exposure to interest rate movements. Interest rate swaps, designated as cash flow hedges, involve the receipt of variable-rate amounts in exchange for fixed-rate payments over the life of the agreements without exchange of the underlying principal amount.
We do not use derivatives for trading or speculative purposes. Further, we have a policy of only entering into contracts with major financial institutions based upon their credit ratings and other factors. When viewed in conjunction with the underlying and offsetting exposure that the derivatives are designed to hedge, we have not sustained a material loss from these hedges.
We record all derivatives on the balance sheet at fair value. The accounting for changes in the fair value of derivatives depends on the intended use of the derivative and the resulting designation. Derivatives used to hedge the exposure to changes in the fair value of an asset, liability or firm commitment attributable to a particular risk, such as interest rate risk, are considered fair value hedges. Derivatives used to hedge the exposure to variability in expected future cash flows or other types of forecasted transactions are considered cash flow hedges.
Index
For derivatives designated as cash flow hedges, the effective portion of changes in the fair value of the derivative is initially reported in other comprehensive income (outside of earnings) and subsequently reclassified to earnings when the hedged transaction affects earnings, and the ineffective portion of changes in the fair value of the derivative is recognized directly in earnings. Hedge ineffectiveness is measured by comparing the changes in fair value or cash flows of the derivative hedging instrument with the changes in fair value or cash flows of the designated hedged item or transaction. For derivatives not designated as hedges, changes in fair value are recognized in earnings. See Note 11 for additional information related to our derivative and hedging activities.
Treasury Shares
We record the purchase of treasury shares at cost. From time to time, we may reissue these shares. When shares are reissued, we account for the issuance based on the "first in, first out" method. For additional information regarding treasury shares, see Note 14. We commonly use our treasury shares to provide for restricted share award grants and acquire treasury shares upon the forfeiture of restricted shares, upon the termination of employment prior to vesting and upon surrender of restricted shares in satisfaction of income tax liabilities upon vesting events.
New Accounting Standards
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. See Note 3 for additional information related to how ASU 2014-08 affects our current reporting. 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.
Revenue
In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606) ("ASU 2014-09"). ASU 2014-09 is a comprehensive new revenue recognition model requiring a company to depict the transfer of goods or services to a customer at an amount reflecting the consideration it expects to receive in exchange for those goods or services. In adopting ASU 2014-09, companies may use either a full retrospective or a modified retrospective approach. Additionally, this guidance requires improved disclosures regarding the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers. ASU 2014-09 is effective for the first interim period within annual reporting periods beginning after December 15, 2016, and early adoption is not permitted. The Company is currently evaluating the impact the adoption of ASU 2014-09 will have on the Company’s financial position or results of operations.
Index
Going Concern
In August 2014, the FASB issued ASU 2014-15, Presentation of Financial Statements - Going Concern (Subtopic 205-40) ("ASU 2014-15"). ASU 2014-15 was issued to give clarity to stakeholders when there are conditions or events that raise substantial doubt about an entity’s ability to continue as a going concern. The guidance calls for, in connection with the preparation of financial statements for each annual and interim reporting period, an evaluation by management over whether there are conditions or events, considered in the aggregate, that raise substantial doubt about the Company’s ability to continue as a going concern within one year after the date that the financial statements are issued (or are available to be issued). ASU 2014-15 is effective for the annual reporting periods ending after December 15, 2016. ASU 2014-15 will become effective for the Company on January 1, 2016. At this time, the adoption of ASU 2014-15 is not expected to impact the Company's consolidated financial statements or disclosures.
Adjustments to Previously Issued Financial Statements
In connection with the preparation of the financial statements as of June 30, 2014, we identified an adjustment related to the reporting of cash expenditures for development fixed asset additions and the related non-cash investing disclosure which impacted the Consolidated Statements of Cash Flows for the Year Ended December 31, 2013, by reducing cash flow from operating activities and cash used for investing activities. To correctly present cash flows expended for development fixed asset additions, the Consolidated Statements of Cash Flows includes an adjustment of $8.3 million to increase net cash flow provided by operating activities, as well as a corresponding increase to net cash flow used for investing activities for the year ended December 31, 2013. We assessed the materiality of the foregoing adjustment on the prior period financial statements by examining and assessing the pertinent quantitative and qualitative criteria, and concluded that it was not material to the prior period. However, we determined it was appropriate to revise the applicable financial statements in this filing with the SEC. The following are selected line items from our Consolidated Statements of Cash Flows for the Year Ended December 31, 2013 illustrating the affect of the adjustment thereon:
		As Previously
(in thousands)		Reported			Adjustment			As Revised
Cash flow from operating activities:
Net change in assets and liabilities:
Accounts payable and accrued expenses		$	(3,267	)	$	8,262		$	4,995
Total adjustments		$	12,268		$	8,262		$	20,530
Net cash flow provided by operating activities		$	73,563		$	8,262		$	81,825
Cash flow from investing activities:
Development fixed asset additions		$	(77,094	)	$	(8,262	)	$	(85,356	)
Net cash flow used for investing activities		$	(211,176	)	$	(8,262	)	$	(219,438	)
Supplemental disclosure of non-cash information:
Net change in accounts payable related to fixed asset additions		$	14,360		$	(8,262	)	$	6,098
There is no impact on these adjustments to the Consolidated Balance Sheets, Consolidated Statement of Shareholders’ Equity or Consolidated Statements of Operations and Comprehensive Income of the Company in any previously reported periods or any interim periods reported during the year ended December 31, 2013.

Acquisition_Development_Constr

Acquisition, Development, Construction and Disposition Activity	12 Months Ended
	Dec. 31, 2014
Acquisition, Development, Construction and Disposition Activity [Abstract]
ACQUISITION, DEVELOPMENT, CONSTRUCTION AND DISPOSITION ACTIVITY	ACQUISITION, DEVELOPMENT, CONSTRUCTION AND DISPOSITION ACTIVITY
	Acquisition Activity
	The following table provides information on the operating property acquired during 2014 (purchase price in thousands):
	Acquisition Date		Property		Location		Units			Purchase Price
	10-Jun-14		Alpha Mill Phase I and Phase II		Charlotte, NC		267			$	45,075
	The following table provides information on operating properties acquired during 2013 (purchase price in thousands):
	Acquisition Date		Property		Location		Units			Purchase Price
	19-Nov-13		Lofts at Weston Lakeside		Cary, NC		215			$	38,300
	18-Nov-13		St. Mary's Square		Raleigh, NC		134			27,325
	10-Oct-13		The Apartments at Blakeney (1)		Charlotte, NC		295			53,180
	27-Sep-13		Rienzi at Turtle Creek		Dallas, TX		152			48,900
	16-Jul-13		Doral West		Doral, FL		388			93,500
							1,184			$	261,205
	-1	Purchase price includes assumed $28.0 million loan. Principal balance of loan assumed approximated fair value at time of acquisition.
	The following table provides information on operating properties acquired during 2012 (purchase price in thousands):
	Acquisition Date		Property		Location		Units			Purchase Price
	28-Aug-12		The Park at Crossroads (1)		Cary, NC		344			$	35,200
	23-Jul-12		21 Forty Medical District		Dallas, TX		396			53,350
	17-Jul-12		Southpoint Village		Durham, NC		211			34,800
	23-May-12		The Apartments at the Arboretum		Cary, NC		205			39,250
	8-May-12		Desmond's Tower (2)		Los Angeles, CA		—			20,000
							1,156			$	182,600
	-1	Purchase price includes assumed $24.9 million loan, with a fair value of $27.6 million.
	-2	In conjunction with our May 2012 acquisition of land for development of an apartment community, we acquired an operating commercial building. This amount represents the purchase price allocation of the commercial building component only. The purchase price allocation of $17.3 million, representing the parking lot to be used for development, is included in the "Consolidated Current Development" table within this Note.
	In addition, on November 6, 2014, we acquired land in Woodland Hills, California for development of a 379-unit apartment community for a purchase price of $15.8 million, included in investing activity in "Development fixed asset additions" in the Statements of Cash Flows.
	The following table presents actual and unaudited pro forma information related to the properties acquired during the years ended December 31, 2014 and 2013, respectively. The pro forma information is presented as if the properties acquired during 2014 were acquired on January 1, 2013, as if the properties acquired during 2013 were acquired on January 1, 2012 and gives pro forma results for those properties acquired in 2012. We recognized acquisition costs, during the year ended December 31, 2014, totaling $185,000, which are included in "Costs associated with acquisitions" in the Consolidated Statements of Operations and Comprehensive Income. Additionally, we recognized acquisition costs totaling $78,000 related to the current year acquisition during the last half of 2013. 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 acquisitions occurred at such time.
	Index
		Year Ended December 31,
	(Pro forma amounts unaudited; in thousands, except per share data)	2014				2013				2012
	Actual revenue from acquisitions	$	1,934			$	6,448			$	7,978
	Actual net income (loss) from acquisitions	17				(240		)		51
	Pro forma revenue	195,140				196,212				184,294
	Pro forma net income applicable to common shares	144,943				63,929				32,210
	Pro forma earnings per common share - basic:
	Pro forma net income applicable to common shares	$	2.52			$	1.24			$	0.7
	Pro forma earnings per common share - diluted:
	Pro forma net income applicable to common shares	$	2.5			$	1.23			$	0.7
	The purchase price allocations for the operating properties acquired were as follows:
		December 31,
	(In thousands)	2014				2013				2012
	Land	$	8,140			$	28,578			$	25,638
	Buildings and improvements	36,044				225,792				150,028
	Furniture and fixtures	468				3,313				3,197
	Existing leases (Other assets) (1)	423				3,522				6,313
	Assumed debt (2) (3)	—				(28,000		)		(27,589		)
	Other liabilities	—				—				101
	Total	$	45,075			$	233,205			$	157,688
	-1	See Note 5 for additional information related to intangible assets identified as existing leases.
	-2	Fair value was equal to principal amount of loan assumed in 2013 at the time of acquisition.
	-3	Fair value amount of loan assumed in 2012 at the time of acquisition; actual principal amount of loan assumed was $24.9 million,
	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. We expect to acquire the remaining two properties based on the closing periods set forth in the following table. Each of these remaining closings is contingent upon the completed construction of the property. Our obligation to purchase these properties is subject to certain closing conditions specified in the agreement. If we choose not to purchase one or more of the properties, 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 deposits, which was, as of December 31, 2014, an aggregate of $10.0 million.  This remaining balance of earnest money deposits represents our maximum exposure to loss until the closing of the remaining portfolio properties. We consider our deposits allocated to the entities developing the properties under construction to be variable interests and the development entities to be variable interest entities for which we are not the primary beneficiary as of this reporting date as we do not have control over the entities. Although we intend to acquire the remaining two properties, and regard our acquisition of each property as probable, there can be no assurance that we will acquire such properties.
	The table below provides details for the two remaining properties we plan to acquire:
	(Dollar amounts in thousands)
	Property		Location		Units			Estimated Closing Period		Purchase Price
	1160 Hammond		Atlanta, GA		345			Q1 2015		$	80,350
	Varela Westshore		Tampa, FL		350			Q2 2015		79,450
					695					$	159,800
	Index
	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 early 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 variable interest entity for which we are not the primary beneficiary as of this reporting date as we do not have control over the entity.
	Development Activity
	During the year ended December 31, 2013, we substantially completed the development of a parcel of land adjacent to our existing San Raphael property in North Dallas, which stabilized operations in the first quarter of 2014. We also entered into two separate partnerships for development; one in which we were a 50.0% partner to develop a 154-unit apartment community located in Monrovia, California, which we refer to as 5th and Huntington, and one in which we are a 50.0% partner to develop a 472-unit apartment community and 19,700 square feet commercial space located in Los Angeles, California, which we refer to as 950 East Third. See Note 6 for additional information related to these partnerships. On February 3, 2015, we purchased our partner's 50.0% interest in 5th and Huntington for $8.4 million, increasing our ownership percentage in the development to 100%. See Note 19 for further information related to this subsequent event.
	On May 28, 2013, we acquired a 3.36 acre parcel of land in the South of Market 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:
	(Dollar amounts in thousands)
										Total
										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	%		249			$	56,800		$	52,373		$	32,006		Q2 2013		Q1 2015
7001 Arlington at Bethesda		Bethesda, MD		98.1	%	(2)	140			$	53,400		$	46,658		$	16,673		Q4 2012		Q2 2015
The Desmond on Wilshire		Los Angeles, CA		100	%		175			$	76,300		$	44,982		$	—		Q2 2013		Q4 2015
Total							564			$	186,500		$	144,013		$	48,679
-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 projections as of February 3, 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.
Index
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	%		410			$	245,000		$	82,647		$	39,172		$	—		$	—	(2)	Q2 2014	Q4 2016
950 East Third		Los Angeles, CA		50	%		472			$	164,000		$	38,505		$	7,730		$	—		$	—		Q3 2014	Q1 2017
Total							882			$	409,000		$	121,152		$	46,902		$	—		$	—
-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 projections as of February 3, 2015.
-2	AEC has guaranteed 100% of a $143.6 million construction loan which had no outstanding balance as of December 31, 2014.
The following table identifies our development activity that is in the planning phase:
(Dollar amounts in thousands)												AEC						AEC
						Estimated			Cost to			Investment			Total			Share of
Name		Location		Ownership %		Total Units (1)			Date			to Date			Debt			Debt
5th and Huntington (2)		Monrovia, CA		50.00%		154			$	15,331		$	7,898		$	—		$	—
Warner Center		Woodland Hills, CA		100.00%		379			$	17,519		$	17,519		$	—		$	—
-1	Based on current projections as of February 3, 2015.
-2	5th and Huntington is an unconsolidated development project as of December 31, 2014. On February 3, 2015, we purchased our partner's 50.0% interest in the partnership for $8.4 million, increasing our ownership percentage in the development to 100%. See Note 19 for further information related to this subsequent event.
Construction Activity
Our subsidiary, Merit, is engaged as a general contractor and construction manager that acts as our in-house construction division and also has provided general contracting and construction management services to third parties.
Disposition Activity
The results of operations and gains related to the sale of operating properties for the year ended December 31, 2014 are reported in income from continuing operations in the accompanying Consolidated Statements of Operations and Comprehensive Income. Prior to adoption of ASU 2014-08 on January 1, 2014, and in all prior periods presented, these results were reported in "Income from discontinued operations," in the accompanying Consolidated Statements of Operations and Comprehensive Income. Furthermore, the results of properties classified as held for sale are now reported in income from continuing operations. See Note 2 for additional information related to how this ASU affects our current reporting.
During 2014, we completed the sale of five properties, with year to date operating income, net of interest expense, of $3.4 million, for an aggregate total sales price of $216.4 million and recognized aggregate gains of $133.3 million. Three of the properties were located in Maryland, one in Tennessee and one in Southeast Florida.
During 2013, we completed the sale of four properties for an aggregate total sales price of $139.0 million and recognized aggregate gains of $52.8 million. One of the properties was located in Georgia, two in Central Ohio and one in Central Florida.
Index
During 2012, we completed the sale of six properties for an aggregate total sales price of $67.3 million and recognized aggregate gains of $26.8 million. Four of the properties were located in Western Michigan, one in Central Ohio and one in Georgia.
"Income from discontinued operations" in the accompanying Consolidated Statements of Operations and Comprehensive Income for the years ended December 31, 2013 and 2012 includes the operating results and related gains recognized for four properties sold in 2013 and six properties sold in 2012. The following table summarizes "Income from discontinued operations:"
(In thousands)		2013				2012
Revenue
Property revenue		$	9,191			$	21,649
Expenses
Property operating and maintenance		4,233				10,351
Depreciation and amortization		1,779				5,606
Total expenses		6,012				15,957
Operating income		3,179				5,692
Interest expense		—				(1,811		)
Operating income, net of interest expense		3,179				3,881
Gain on disposition of properties		52,828				26,849
Income from discontinued operations		$	56,007			$	30,730
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"). For the year ended December 31, 2014, in conjunction with the sale of one property in Nashville, Tennessee for $53.3 million on April 2, 2014, and the acquisition of land in Woodland Hills, California for $15.8 million on November 6, 2014, HRES was paid commissions totaling $400,000. For the year ended December 31, 2013, in conjunction with the sale of three properties and our joint venture to develop 950 East Third land, HRES received commissions totaling $1.1 million. The aggregate value of those transactions was $130.9 million. These transactions were approved by the Company's independent directors in compliance with Company policy.

Restricted_Cash

Restricted Cash	12 Months Ended
	Dec. 31, 2014
Restricted Cash [Abstract]
RESTRICTED CASH	RESTRICTED CASH
	Restricted cash, some of which is required by our lenders, includes residents' security deposits, reserve funds for replacements, escrow deposits related to property sales held for 1031 exchanges and other escrows held for the future payment of real estate taxes and insurance. The reserve funds for replacements are intended to provide cash to defray future costs that may be incurred to maintain the associated property.
	Restricted cash is comprised of the following:
		December 31,
	(In thousands)	2014		2013
	Resident security deposits	$	1,128	$	1,524
	Other escrows	43,295		20
	Deferred compensation	746		560
	Escrows and reserve funds for replacements
	required by mortgages	1,192		1,361
		$	46,361	$	3,465
	Restricted resident security deposits are held in separate bank accounts in the name of the properties for which the funds are being held. See Note 18 for additional information related to the deferred compensation program.

Goodwill_and_Other_Assets

Goodwill and Other Assets	12 Months Ended
	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
GOODWILL AND OTHER ASSETS	GOODWILL AND OTHER 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. During the year ended December 31, 2014, we wrote-off $186,000 of our goodwill as a result of property dispositions. The carrying value of our goodwill as of December 31, 2014 and December 31, 2013, was $1.3 million and $1.5 million, respectively. 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, 2014, 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.
	Other Assets, Net
	Other assets, net, consist of the following:
		December 31,
	(In thousands)	2014			2013
	Intangible assets	$	5,812		$	9,834
	Less: accumulated amortization	(4,925		)	(6,093		)
		887			3,741
	Prepaid expenses	4,741			4,029
	Deferred financing costs, net	7,177			8,559
	Deposits on potential future acquisitions	14,006			17,943
	Other assets	2,336			3,687
		$	29,147		$	37,959
	Property Acquisitions. 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 is approximately 6 to 12 months. Due to the short-term nature of residential leases, we believe that 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 9 for additional information related to this lease.
	In connection with one multifamily property acquisition completed during 2014, as discussed in Note 3, we recorded total intangible assets in the amount of $423,000 related to existing leases, which were amortized over 7 months.
	In connection with five multifamily property acquisitions completed during 2013, as discussed in Note 3, we recorded total intangible assets in the amount of $3.5 million related to existing leases, which are being amortized over 12 months.
	Our intangible assets related to existing leases consist of the following:
	(In thousands)	December 31,
		2014			2013
	Gross carrying amount	$	5,812		$	9,834
	Less: accumulated amortization	(4,925		)	(6,093		)
		$	887		$	3,741
	Index
	The aggregate intangible asset amortization expense for the years ended December 31, 2014, 2013 and 2012 was $3.3 million, $3.9 million and $4.9 million, respectively.
	As of December 31, 2014, the scheduled amortization for each of the next five years are as follows (in thousands):
	2015	$	374
	2016	374
	2017	139
	2018	—
	2019	—
		$	887
	Gross deferred tax assets of $6.9 million at December 31, 2014 and 2013 are also included in intangible assets. See Note 10 for additional information related to income taxes.
	Deferred Financing Costs
	Amortization expense for deferred financing costs, including amortization classified in income from discontinued operations, was $1.9 million, $2.0 million and $2.1 million for the years ended December 31, 2014, 2013 and 2012, respectively.

Investment_In_Unconsolidated_E

Investment In Unconsolidated Entities (Notes)	12 Months Ended
	Dec. 31, 2014
Equity Method Investments and Joint Ventures [Abstract]
Equity Method Investments and Joint Ventures Disclosure [Text Block]	INVESTMENT IN UNCONSOLIDATED ENTITIES
	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, a 410-unit apartment community with 40,000 square feet commercial space and underground parking located in San Francisco, California. See Note 3 for more information related to this development. We are a 50.01% partner in this partnership. Our partner, AIG, has contributed $37.6 million to the partnership. The land upon which the partnership is developing was purchased by us for $46.6 million on May 28, 2013. As of December 31, 2013, this land was included in our consolidated financial statements. 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. Both partners have equal voting rights with respect to all major decisions, and all such decisions must be unanimous, including, among other things, development planning, budgeting and operational budgets. We perform construction management and property management services in accordance with the approved budgets for which we receive fees. For the year ended December 31, 2014, we have recognized $360,000 of the construction management fee. As the partnership is not sufficiently funded to finance the activities of the entity, and not all of the capital will be funded up front, the partnership is not deemed to have sufficient equity, and has therefore been determined to be a variable interest entity. It has also been determined that we do not control the decisions that most significantly affect the economics of the entity, and that we do not hold a controlling financial interest in the entity. As such, our investment in the entity is accounted for in our consolidated financial statements using the equity method. At December 31, 2014, we have a cumulative basis difference in the partnership of $1.3 million due to capitalization of interest on our investment and internal payroll and overhead costs directly related to the development of this property. This excess of our investment over our equity in the underlying net assets of the joint venture 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. 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 December 31, 2014. 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 7 for more information related to this loan and Note 9 for more information related to the guarantees. Our maximum exposure to loss, as a result of our involvement in this entity, is the carrying value of our investment, which was $39.2 million as of December 31, 2014.
	Index
	950 East Third
	During the year ended December 31, 2013, we entered into a partnership agreement with Legendary Investors Group No. 1 LLC ("Legendary"), an unrelated third-party, for the development and operation of 950 East Third, a 472-unit apartment community with 19,700 square feet commercial space located in Los Angeles, California. We are a 50.0% partner with Legendary, who contributed the land at a value of $30.0 million to the partnership. As of December 31, 2014, we have contributed $7.7 million to the partnership. We expect to fund the remaining portion of our capital contribution during the development and construction process. Both partners have equal voting rights with respect to all major decisions, and all such decisions must be unanimous, including, among other things, development planning, budgeting and operational budgets. We perform construction management and property management services in accordance with the approved budgets for which we receive fees. For the year ended December 31, 2014, we have recognized $250,000 of the construction management fee. As the partnership is not sufficiently funded to finance the activities of the entity, and not all of the capital will be funded up front, the partnership is not deemed to have sufficient equity, and has therefore been determined to be a variable interest entity. It has also been determined that we do not control the decisions that most significantly affect the economics of the entity, and that we do not hold a controlling financial interest in the entity. As such, our investment in the entity is included in our consolidated financial statements using the equity method. At December 31, 2014, we have a cumulative basis difference in the partnership of $480,000 due to the capitalization of interest on our investment and internal payroll and overhead costs directly related to the development of this property. This excess of our investment over our equity in the underlying net assets of the partnership 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 this entity, is the carrying value of our investment, which was $7.7 million as of December 31, 2014. See Note 3 for more information related to this development.
	5th and Huntington
	During the year ended December 31, 2013, we entered into a partnership agreement with LPC MM Monrovia, LLC ("Lincoln"), an unrelated third-party, for the limited purpose of acquiring a property in Monrovia, California, 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 were a 50.0% partner with Lincoln, who contributed $7.5 million to the partnership. As of December 31, 2014, we had contributed $7.9 million to the partnership. Any future equity capital needs would have been funded on a 50/50 basis by the partners. Both partners had equal voting rights with respect to all major decisions, and all such decisions would have been unanimous, including, among other things, development planning, budgeting and operational budgets. Lincoln performed the day-to-day activities on behalf of the partnership. As the partnership was not sufficiently funded to finance the activities of the entity, and not all of the capital was funded up front, the partnership was not deemed to have sufficient equity, and had therefore been determined to be a variable interest entity. It was also determined that we did not control the decisions that most significantly affect the economics of the entity, and that we did not hold a controlling financial interest in the entity. As such, our investment in the entity was included in our consolidated financial statements using the equity method. At December 31, 2014, we had a cumulative basis difference in the partnership of $500,000 due to the capitalization of interest on our investment and internal payroll and overhead costs directly related to the development of this property. This excess of our investment over our equity in the underlying net assets of the partnership is included in "Investment in unconsolidated entities" in our Consolidated Balance Sheets. Our maximum exposure to loss, as a result of our involvement in this entity, is the carrying value of our investment, which was $7.9 million as of December 31, 2014. See Note 3 for more information related to this development. On February 3, 2015 we purchased Lincoln's 50.0% interest in the partnership for $8.4 million, increasing our ownership percentage in the development to 100%. See Note 19 for further information related to this subsequent event.

Debt

Debt	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
DEBT	DEBT
	The following table identifies our total debt outstanding and weighted average interest rates:
		31-Dec-14						31-Dec-13
					Weighted					Weighted
		Balance			Average			Balance		Average
	(Dollar amounts in thousands)	Outstanding			Interest Rate			Outstanding		Interest Rate
	Fixed Rate Debt:
	Secured	$	223,934		4.8	%		$	271,374	4.9	%
	Unsecured - notes	250,000			4.4	%		250,000		4.4	%
	Total Fixed Rate Debt	473,934			4.6	%		521,374		4.7	%
	Variable Rate Debt Swapped to Fixed:
	Unsecured - term loan	125,000			2.7	%		125,000		3	%
	Total Variable Rate Debt Swapped to Fixed	125,000			2.7	%		125,000		3	%
	Variable Rate Debt Unhedged:
	Secured	48,679			1.5	%		8,100		1.5	%
	Unsecured - revolving credit facility	76,500			1.5	%		133,500		1.5	%
	Unsecured - term loan	25,000			1.6	%		25,000		1.9	%
	Total Variable Rate Debt Unhedged	150,179			1.5	%		166,600		1.5	%
	Total Debt	$	749,113		3.7	%		$	812,974	3.8	%
	Real estate assets pledged as collateral for all debt had a net book value of $324.1 million and $389.1 million at December 31, 2014 and 2013, respectively.
	As of December 31, 2014, the scheduled payments of principal on all debt for each of the next five years and thereafter, are as follows (in thousands):
	2015		$	21,446
	2016		89,502
	2017		77,906
	2018		49,066
	2019		12,005
	Thereafter		497,797
	Net unamortized premium		1,391
			$	749,113
	Cash paid for interest net of capitalized interest was $25.2 million, $24.9 million and $29.4 million for the years ended December 31, 2014, 2013 and 2012, respectively. Capitalized interest was $4.8 million, $3.6 million and $1.5 million for the years ended December 31, 2014, 2013 and 2012, respectively.
	Index
	The following table provides information on loans repaid during 2014:
			Loans Repaid
	(Dollar amounts in thousands)					Interest
	Property		Amount			Rate (2)
	Residence at White River		$	9,221		5.40%
	Spring Valley		10,817			5.40%
	The Alexander at Ghent		24,500			5.60%
	Total / weighted average rate		$	44,538		5.50%	(1)
	-1	Represents weighted average interest rate for the loans listed.
	-2	Represents interest rate at the time of repayment.
	Mortgage Notes Payable
	At December 31, 2014, mortgage notes payable consisted of 10 project specific loans. Each loan is collateralized by the respective real estate and resident leases. One construction loan was collateralized by the development property located in Bethesda, Maryland and one construction loan was collateralized by the development property located in Dallas, Texas. The balance on these construction loans as of December 31, 2014 was $16.7 million and $32.0 million, respectively.
	At December 31, 2013, mortgage notes payable consisted of 13 project specific loans. Each loan is collateralized by the respective real estate and resident leases. One construction loan was collateralized by the development property located in Bethesda, Maryland and one construction loan was collateralized by the development property located in Dallas, Texas. The balance on these construction loans as of December 31, 2013 was $2.2 million and $5.9 million, respectively. During 2013, we repaid five loans for a total of $129.3 million with an average interest rate of 6.1% per annum.
	Mortgages payable generally require monthly installments of principal and interest and mature at various dates through 2022. Certain of our mortgages require payments of interest only prior to maturity. Under certain of the mortgage agreements, we are required to make escrow deposits for taxes, insurance and replacement of project assets.
	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 at December 31, 2014. 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 December 31, 2014.
	Unsecured Revolving Credit Facility
	On June 19, 2013, we amended our $350 million unsecured revolving credit facility. Among other modifications, the amendment extends the maturity date from January 12, 2016 to June 15, 2017, and reduces the interest spread and facility fee across the pricing grid. Total costs associated with this amendment were $1.2 million. There were outstanding borrowings of $76.5 million on this facility at December 31, 2014, with a weighted average interest rate of 1.47% per annum. At December 31, 2013, there were outstanding borrowings of $133.5 million with a weighted average interest rate of 1.47% per annum. We are required to comply with certain financial covenants under the unsecured revolving credit facility, including outstanding secured and unsecured indebtedness, consolidated tangible net worth, fixed charge coverage, unsecured interest coverage, dividend payout ratio and permitted investments. We were in compliance with the covenants at December 31, 2014.
	On July 25, 2014, we amended our unsecured revolving credit facility to implement modifications corresponding to the unsecured term loan modifications.
	Index
	Unsecured Term Loan
	On June 19, 2013, we amended our unsecured term loan to implement modifications corresponding to the revolving credit facility modifications. We are required to comply with certain financial covenants similar to those contained in the unsecured revolving credit facility. We were in compliance with the covenants at December 31, 2014.
	On July 25, 2014, we amended and restated our $150 million unsecured term loan. Among other modifications, the amendment extended the maturity date from January 3, 2018 to January 3, 2020, and reduced the interest rate spread across the pricing grid. The term loan currently bears interest at LIBOR plus a spread of 140 basis points. The interest rate spread over LIBOR is based on the Company's credit ratings and may range from 90 to 190 basis points for LIBOR-based loans. Total costs associated with this amendment were $800,000.
	Unsecured Debt
	On January 22, 2013, we completed the issuance of $150 million of unsecured senior notes. The notes were offered in a private placement with two maturity tranches: $63.0 million with an 8-year maturity at a fixed rate of 4.02% per annum, and $87.0 million with a 10-year maturity at a fixed rate of 4.45% per annum. The $150 million total issuance had a weighted average term of 9.2 years and a weighted average interest rate of 4.27% per annum. Proceeds from the issuance were used to repay borrowings on the unsecured revolving credit facility. Total costs associated with this issuance were $1.0 million.
	On October 21, 2013, we completed the issuance of $100 million of unsecured senior notes. The notes were offered in a private placement with two maturity tranches: $45.0 million with an 7-year maturity at a fixed rate 4.29% per annum, and $55.0 million with a 10.2-year maturity at a fixed rate of 4.94% per annum. The $100 million total issuance had a weighted average term of 8.8 years and a weighted average interest rate of 4.65% per annum. Proceeds from the issuance were used to repay borrowings on the revolving credit facility. Total costs associated with this issuance were $950,000.
	We are required to comply with certain financial covenants under the unsecured senior notes, including outstanding indebtedness, fixed charge coverage, unsecured interest coverage and unencumbered physical occupancy. We were in compliance with the covenants at December 31, 2014.

Noncontrolling_Interests

Noncontrolling Interests	12 Months Ended
	Dec. 31, 2014
Noncontrolling Interest [Abstract]
NONCONTROLLING INTERESTS	NONCONTROLLING INTERESTS
	Noncontrolling Redeemable Interest
	In 1998, in conjunction with the acquisition of an operating partnership that owned two apartment communities, one of which was sold in October 2005, we issued a total of 522,032 operating partnership units ("OP units"). Holders of OP units were entitled to receive cumulative distributions per OP unit equal to the per share distributions on our common shares. When the OP units were presented for redemption, we were obligated to redeem those OP units for either common shares exchangeable on a one-for-one basis, or the cash equivalent amount, determined as the average closing price for our common shares over the 20-day period preceding the redemption, at our option. On October 23, 2013, we consummated a subsidiary merger transaction that had the effect of converting the remaining 74,083 OP units into a right to receive cash merger consideration, pursuant to which we paid $1.4 million on November 6, 2013. As of December 31, 2013, there were no remaining OP units as all remaining units had been redeemed for cash or canceled in the merger. No OP units were redeemed during 2012.
	Index
	Activity related to the noncontrolling redeemable interest is as follows:
		For the year ended December 31,
	(In thousands)		2013				2012
	Balance at beginning of period		$	1,734			$	1,734
	Net income attributable to noncontrolling redeemable interest		42				54
	Distribution to noncontrolling redeemable interest		(42		)		(54		)
	Redemption of Operating Partnership units		(1,734		)		—
	Balance at end of period		$	—			$	1,734
	Noncontrolling Interest
	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 variable interest entity 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 meets the criteria to be classified as a component of permanent equity.
	On September 24, 2010, we entered into a partnership agreement with Bristol Development Group, an unrelated third-party, for the development of Vista Germantown, a 242-unit apartment community located in downtown Nashville, Tennessee. We contributed $9.4 million to the partnership and held a 90.0% equity interest in the partnership. In February 2013, we funded the redemption of the interest of the minority 10.0% partner of this partnership for $4.5 million, as a result of which we owned a 100% interest in Vista Germantown as of February 2013. On April 2, 2014, we disposed of Vista Germantown for a sales price of $53.3 million.
	The following table provides details of the activity related to noncontrolling interests:
		December 31,
	(In thousands)	2014				2013
	Balance at beginning of period	$	350			$	1,344
	Net income	—				3
	Purchase of noncontrolling interest	—				(997		)
	Balance at end of period	$	350			$	350
	The following table provides details of the activity related to changes in ownership of noncontrolling interests:
		December 31,
	(In thousands)	2014				2013
	Net income attributable to AERC	$	144,711			$	61,250
	Decrease in equity for purchase of noncontrolling interest	—				(3,547		)
	Change from net income attributable to AERC and net
	transfers to noncontrolling interest	$	144,711			$	57,703

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES
	Leases
	We had no equipment leased under capital leases at December 31, 2014 and 2013. We lease certain equipment and facilities under operating leases. Future minimum lease payments under all non-cancellable operating leases in which we are the lessee are immaterial.
	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.
	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 (the "Bankruptcy Case").
	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 appeal, 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 $887,000 at December 31, 2014. 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.
	On December 26, 2014, the United States District Court for the Northern District of Ohio (the "Court") entered an order approving a settlement and dismissing a shareholder derivative and class action captioned Monson v. Friedman, et al. (the "Action"). Pursuant to the settlement, and in exchange for releases and a dismissal of the Action with prejudice, Mr. Jeffrey I. Friedman voluntarily relinquished, and the Company rescinded, 63,714 of the 125,000 options awarded to him in 2012, and for the twelve-month period following final settlement, the Company will not award any stock options to Mr. Friedman. Also, the Company will implement additional processes relating to the future granting of equity awards and pay for plaintiffs' counsel fees and expenses approved by the Court with respect to the Action. We maintain insurance that will help defray the cost of the settlement, and the settlement did not have a material impact on our financial results.
	Index
	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 or loss, if any, will not have a material adverse impact on our financial statements.
	Guarantees
	We may guarantee mortgage debt of our wholly owned subsidiaries and the properties for which we are a joint venture partner in whole or in part (i.e. for so-called "nonrecourse carve outs"), and some subsidiaries that own unencumbered property guarantee the Company's obligations under the unsecured revolving credit facility, unsecured term loan and unsecured notes. In the normal course of business, we may enter into contractual arrangements under which we may agree to indemnify the third party to such arrangements from any losses incurred relating to the services they perform on behalf of the Company or for losses arising from certain events as defined within the particular contract, which may include, for example, litigation or claims relating to past performance. Such indemnification obligations may not be subject to maximum loss clauses. Historically, payments made related to these indemnifications have not been material.
	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 December 31, 2014.

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES
	Income Taxes
	We have elected to be taxed as a REIT under the Internal Revenue Code of 1986 (the "Code"), as amended. As a REIT, we are entitled to a tax deduction for dividends paid to shareholders, thereby effectively subjecting the distributed net income to taxation at the shareholder level only, provided we distribute at least 90.0% of our taxable income and meet certain other qualifications.
	Our two REIT subsidiaries that have historically engaged in third party property and asset management and third party construction services, respectively, have elected to be treated as Taxable REIT Subsidiaries ("TRS") and operate as C-corporations under the Code. Accordingly, these TRS entities separately account for income taxes. Taxes are recorded for these two TRS subsidiaries to the extent they recognize net profits for both financial statement and income tax purposes. The 2014, 2013 and 2012 net operating loss carry forwards for these two TRS subsidiaries, in the aggregate, are approximately $13.4 million, $13.3 million and $13.2 million, respectively, and expire during the years 2018 to 2034.
	The gross deferred tax assets were $6.9 million, $6.9 million and $6.9 million at December 31, 2014, 2013 and 2012, respectively, and relate principally to net operating losses of the two TRS subsidiaries. Gross deferred tax liabilities of $254,000, $254,000 and $246,000 at December 31, 2014, 2013 and 2012, respectively, relate primarily to tax basis differences in fixed assets and intangibles. The deferred tax valuation allowance was $6.7 million, $6.6 million and $6.6 million at December 31, 2014, 2013 and 2012, respectively. We reserve for net deferred tax assets when we believe it is more likely than not that they will not be realized. The deferred tax assets and the deferred tax valuation allowance are recorded in "Other assets, net" and the deferred tax liabilities are recorded in "Accounts payable and other liabilities."
	Index
	At December 31, 2014 and 2013, our net tax basis of properties is below the amount set forth in the Consolidated Balance Sheets by $5.4 million and $31.2 million, respectively.
	Reconciliation between GAAP net income and taxable income:
					Year Ended December 31,
	(In thousands)				2014				2013				2012
	GAAP net income				$	144,711			$	61,250			$	30,592
	Add:		GAAP net income of taxable REIT subsidiaries
			and noncontrolling redeemable interest, net		92				15				1,224
	GAAP net income from REIT operations (1)				144,803				61,265				31,816
	Add:		Book depreciation and amortization		65,437				61,834				57,672
	Less:		Tax depreciation and amortization		(42,467		)		(41,661		)		(39,835		)
			Book/tax differences on gains from
			capital transactions		(112,844		)		(50,472		)		(19,128		)
	Other book/tax differences, net				(2,602		)		(4,616		)		1,088
	Taxable income before adjustments				52,327				26,350				31,613
	Less:		Capital gain		(20,410		)		(2,356		)		(7,762		)
	Taxable income subject to dividend requirements				$	31,917			$	23,994			$	23,851
	-1	All adjustments to GAAP net income from REIT operations are net of amounts attributable to taxable REIT subsidiaries and noncontrolling interests.
	Reconciliation between cash dividends paid and dividends paid deduction:
			Year Ended December 31,
	(In thousands)		2014				2013				2012
	Cash dividends paid		$	43,919			$	38,933			$	32,406
	Add: Dividends designated from following year		10,473				—				—
	Less: Portion designated as capital gain distribution		(20,403		)		(2,356		)		(7,762		)
	Less: Return of capital		—				(12,583		)		(793		)
	Dividends paid deduction		$	33,989			$	23,994			$	23,851
	Dividends Per Share
	Total dividends per common share and the related components for the years ended December 31, 2014, 2013 and 2012, as reported for income tax purposes, were as follows:
	Year Ended December 31, 2014
							Non-Taxable				Total				Unrecaptured
			Ordinary				Return of				Capital				Section 1250
	Date Paid		Income				Capital				Gain				Gain		Dividends
	2/3/14		$	0.118729			$	—			$	0.071271			$	0.017614	$	0.19
	5/1/14		0.118729				—				0.071271				0.017614		0.19
	8/1/14		0.118729				—				0.071271				0.017614		0.19
	11/3/14		0.124978				—				0.075022				0.018541		0.2
	1/30/15	(1)	0.11461				—				0.068799				0.017003		0.183409
			$	0.595775			$	—			$	0.357634			$	0.088386	$	0.953409
	-1	Represents a portion of the dividend paid on January 30, 2015. The remaining portion of this dividend will be reported for the year ended December 31, 2015 for income tax purposes.
	Index
	Year Ended December 31, 2013
							Non-Taxable				Total				Unrecaptured
			Ordinary				Return of				Capital				Section 1250
	Date Paid		Income				Capital				Gain				Gain		Dividends
	2/1/13		$	0.129355			$	0.049149			$	0.011496			$	0.011496	$	0.19
	5/1/13		0.129355				0.049149				0.011496				0.011496		0.19
	8/1/13		0.129355				0.049149				0.011496				0.011496		0.19
	11/1/13		0.129355				0.049149				0.011496				0.011496		0.19
			$	0.51742			$	0.196596			$	0.045984			$	0.045984	$	0.76
	Year Ended December 31, 2012
							Non-Taxable				Total				Unrecaptured
			Ordinary				Return of				Capital				Section 1250
	Date Paid		Income				Capital				Gain				Gain		Dividends
	2/1/12		$	0.140533			$	0.009077			$	0.02039			$	0.017826	$	0.17
	5/1/12		0.1488				0.009611				0.021589				0.018875		0.18
	8/1/12		0.1488				0.009611				0.021589				0.018875		0.18
	11/1/12		0.1488				0.009611				0.021589				0.018875		0.18
			$	0.586933			$	0.03791			$	0.085157			$	0.074451	$	0.71

Derivative_and_Hedging_Activit

Derivative and Hedging Activities	12 Months Ended
	Dec. 31, 2014
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. See Note 2 for additional information related to our derivative instruments and hedging policy.
	As of December 31, 2014, 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		2		$125.0 million
	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 December 31, 2014, 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. See Note 12 for additional information.
	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 December 31, 2014, 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. See Note 12 for additional information.
	In January 2015, we entered into two new forward starting interest rate swaps. See Note 19 for additional information.
	Index
	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 December 31, 2014						As of December 31, 2013
	(In thousands)	Balance Sheet Location		Fair Value				Balance Sheet Location		Fair Value
	Derivatives designated
	as hedging instruments:
	Interest rate swap	Other assets, net		$	256			Other assets, net		$	1,573
	Fair Value of Derivative Instruments
		Liability Derivatives
		As of December 31, 2014						As of December 31, 2013
	(in thousands)	Balance Sheet Location		Fair Value				Balance Sheet Location		Fair Value
	Derivatives designated
	as hedging instruments:
	Interest rate swap	Accounts payable and						Accounts payable and
		other liabilities		$	1,349			other liabilities		$	2,275
	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
	(In thousands)		Location of Gain or		Year Ended
	Derivatives in Cash Flow Hedging		(Loss) Recognized		December 31,				December 31,				December 31,
	Relationships (Interest Rate Swaps)		in Income on Derivative		2014				2013				2012
	Amount of gain/(loss) recognized in OCI on derivative				$	(1,790	)		$	1,454			$	(2,529	)
	Amount of loss reclassified from accumulated
	OCI into interest expense		Interest expense		$	(1,399	)		$	(778	)		$	—
	Amount of gain/(loss) recognized in income
	on derivative (ineffective portion and amount
	excluded from effectiveness testing)		Other expense		$	—			$	—			$	—
	Index
	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
											Net Amounts of				in 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-Dec-14
	Offsetting Derivative
	Assets		$	256			$	—			$	256			$	—	$	—	$	256
	Liabilities		$	1,349			$	—			$	1,349			$	—	$	—	$	1,349
	31-Dec-13
	Offsetting Derivative
	Assets		$	1,573			$	—			$	1,573			$	—	$	—	$	1,573
	Liabilities		$	2,275			$	—			$	2,275			$	—	$	—	$	2,275
	As of December 31, 2014, the fair value of the derivative in a liability position, excluding any adjustment for nonperformance risk, was $1.4 million. As of December 31, 2014, 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 December 31, 2014, we could have been required to settle our obligations under the agreement at its termination value of $1.4 million, which includes accrued interest of $92,000. 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	12 Months Ended
	Dec. 31, 2014
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:
	Ÿ	Level 1 inputs utilize quoted prices (unadjusted) in active markets for identical assets or liabilities that we have the ability to access;
	Ÿ	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
	Ÿ	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.
	Index
	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.
	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 December 31, 2014. 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 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		—
					Fair Value at December 31, 2013 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		$	279,474	$	—	$	—	$	284,886
	Unsecured debt		533,500		—		530,022		—

Supplemental_Disclosure_of_Cas

Supplemental Disclosure of Cash Flow Information	12 Months Ended
	Dec. 31, 2014
Supplemental Cash Flow Information [Abstract]
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION	SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION
	The following table summarizes our non-cash investing and financing activities which are not reflected in the Consolidated Statements of Cash Flows:
		Year Ended December 31,
	(In thousands)	2014			2013			2012
	Dividends declared but not paid	$	12,886		$	12,178		$	10,149
	Issuance of shares for share-based compensation	1,969			—			1,916
	Net change in accounts payable related to fixed asset additions (1)	7,890			6,098			1,362
	Net change in accounts payable and security deposits
	related to disposition of operating properties	(698		)	(890		)	(638		)
	Net change in accounts payable and security deposits
	related to acquisition of operating properties	117			1,800			1,072
	Deconsolidation of net assets	26,238			—			—
	Mortgage loan assumed (2) (3)	—			28,000			27,589
	-1	Refer to Note 2 for information on adjustments made to previously issued financial statements.
	-2	The principal balance on loan assumed in 2013 approximated fair value at time of acquisition.
	-3	The fair value amount of loan assumed in 2012 at time of acquisition; the principal balance at time of acquisition was $24.9 million. Fair value was determined based on an interest rate of 3.1%.

Common_Treasury_and_Preferred_

Common, Treasury and Preferred Shares	12 Months Ended
	Dec. 31, 2014
Common, Treasury and Preferred Shares [Abstract]
COMMON, TREASURY AND PREFERRED SHARES	COMMON, TREASURY AND PREFERRED SHARES
	Common Shares
	In April 2013, we registered an at-the-market ("ATM") program allowing us to sell up to $75 million of our common shares in open market transactions at the then current market price per share. As of December 31, 2013, we sold 107,498 common shares under this ATM program for total gross proceeds of $2.0 million. The proceeds were used for general corporate purposes. No common shares were sold under this ATM program during the year ended December 31, 2014.
	Under Forward Sale Agreements ("FSAs") that we entered into with forward purchasers on May 29, 2013, we agreed to sell 6,500,000 common shares plus an option to purchase up to 975,000 additional common shares, of which 547,958 common shares were exercised on July 2, 2013, for a total of 7,047,958 common shares at a public offering price of $17.25 per share that was settled on October 1, 2013.
	We had the option to settle the FSAs by cash or net share settlement for all or a portion of our obligation under the FSAs. We chose to physically settle the FSAs by issuing 7,047,958 common shares of our common stock to the forward purchasers, who at settlement paid us the proceeds less certain adjustments from their sale of borrowed shares to the underwriters, including the third quarter dividend.
	On October 1, 2013, by delivering 7,047,958 common shares to the forward purchasers at a public offering price of $17.25 per share, we received net proceeds of approximately $115.1 million based on the adjusted net settlement price of $16.33 per share, inclusive of the underwriting discount, estimated costs and the deduction for the third quarter dividend. Net proceeds were used to partially repay our scheduled debt maturities for 2013 consisting of five mortgage loans totaling approximately $129.3 million.
	Prior to settlement, we classified the FSAs as equity transactions because the forward sale transactions were indexed to our own stock and physical settlement was within our control. As a result of this classification, no amounts were recorded in the consolidated financial statements until settlement of each FSA.
	Index
	Whether we decided to physically settle or net share settle the FSAs, delivery of our shares upon settlement resulted in dilution to our earnings per share ("EPS") at the date of the settlement. Any dilutive effect of the FSAs on our EPS occurred only during periods when the average market price per share of our common stock during that reporting period was above the per share forward sale price.
	On June 27, 2012, we sold 6,325,000 of our common shares in a public offering at a price of $14.40 per share, which resulted in total net proceeds of approximately $87.2 million. Of the 6,325,000 shares sold in this offering, we issued all of the 3,403,333 common shares then remaining in treasury and 2,921,667 authorized and previously unissued common shares. The proceeds were used to fund property acquisitions and development and for general corporate purposes.
	During 2012, we sold 681,178 shares under our $25 million ATM program for total net proceeds of $11.1 million. The proceeds were used to reduce borrowings on our unsecured revolving credit facility and for general corporate purposes. At June 30, 2012, all $25 million of common shares available for issuance under the ATM have been sold and the program has been completed.
	Treasury Shares
	In December 2008, our Board of Directors authorized the repurchase of up to $25 million of our common and/or preferred shares. This authorization is in addition to the $1.3 million remaining on our $50 million authorization that was originally approved by our Board of Directors in July 2005 and October 2006. As of December 31, 2014, we had repurchased 3,825,125 common shares under these plans at a cost of $41.1 million and 389,500 preferred depositary shares at a cost of $7.6 million. There were no common shares repurchased after the fourth quarter of 2007 and no preferred shares repurchased after the fourth quarter of 2008 under this authorization. Additionally, we have a policy that allows employees to pay their portion of the income taxes related to restricted shares vesting by surrendering a number of shares to us equal in value on the day of vesting to the amount of taxes due up to the statutory withholding amount.
	During the year ended December 31, 2014, a total of 175,287 restricted shares had vested.
	Preferred Shares
	We are authorized to issue a total of 9,000,000 Preferred Shares, designated as follows:
	•	3,000,000 Class A Cumulative Preferred Shares, of which 225,000 have been designated as 9.75% Class A Cumulative Redeemable Preferred Shares and were redeemed in 2005.
	•	3,000,000 Class B Cumulative Preferred Shares, of which 400,000 have been designated as Class B Series I Cumulative Preferred Shares reserved for issuance in connection with our Shareholder Rights Plan and 232,000 have been designated as 8.7% Class B Series II Cumulative Redeemable Preferred Shares and are discussed below.
	•	3,000,000 Noncumulative Preferred Shares.
	At December 31, 2014, no preferred shares were outstanding.
	Shareholder Rights Plan
	In December 2014, the Board of Directors approved the termination of our Shareholder Rights Plan (the "Plan"). The Plan was adopted in January 1999 and the Rights were distributed on January 29, 1999, to shareholders of record on that date. The initial distribution of Rights was not taxable to shareholders. To implement the Plan, the Board of Directors declared a distribution of one Right for each of our outstanding common shares. Each Right entitled the holder to purchase from us 1/1,000th of a Class B Series I Cumulative Preferred Share (a " Class B Preferred Share") at a purchase price of $40 per Right, subject to adjustment. One one-thousandth of a Class B Preferred Share was intended to be approximately the economic equivalent of one common share.
	Index
	The Rights were traded with our common shares and would have become exercisable if a person or group became the beneficial owner of, or announced an offer to acquire, 15.0% or more of the then outstanding common shares. Thereafter, each Right not owned by the acquiring person or its affiliates would have entitled its holder to purchase, at the Right's then-current exercise price, fractional Class B Preferred Shares (or, in certain circumstances, common shares, cash, property or other securities) having a market value equal to twice the then-current exercise price. In addition, if, after the Rights became exercisable, we would have been acquired in a merger or other business combination transaction with an acquiring person or its affiliates, or sold 50% or more of our assets or earning power to an acquiring person or its affiliates, each Right would have entitled its holder to purchase, at the Right's then-current exercise price, a number of the acquiring person's common shares having a market value of twice the Right's exercise price. No shares were issued under the shareholder rights plan.

Earnings_Per_Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
EARNINGS PER SHARE	EARNINGS PER SHARE
	The exchange of Operating Partnership noncontrolling redeemable interest into common shares was not included in the computation of diluted EPS in 2013 or 2012 because we settled these OP units in cash. There were no OP units outstanding in 2014.
			Year Ended December 31,
	(In thousands, except per share amounts)		2014			2013			2012
	Numerator - basic and diluted:
	Income (loss) from continuing operations		$	144,711		$	5,288		$	(119	)
	Net income attributable to noncontrolling interests		—			(45		)	(19		)
	Allocation to participating securities		(473		)	(19		)	—
	Income (loss) from continuing operations applicable to common shares		$	144,238		$	5,224		$	(138	)
	Income from discontinued operations		$	—		$	56,007		$	30,730
	Allocation to participating securities		—			(209		)	—
	Income from discontinued operations applicable to common shares		$	—		$	55,798		$	30,730
	Denominator - basic:		57,478			51,622			46,063
	Effect of dilutive securities (1)		497			562			—
	Denominator - diluted:		57,975			52,184			46,063
	Net income applicable to common shares - basic:
	Income from continuing operations applicable to common shares		$	2.51		$	0.1		$	—
	Income from discontinued operations		—			1.08			0.66
	Net income applicable to common shares - basic		$	2.51		$	1.18		$	0.66
	Net income applicable to common shares - diluted:
	Income from continuing operations applicable to common shares		$	2.49		$	0.1		$	—
	Income from discontinued operations		—			1.07			0.66
	Net income applicable to common shares - diluted		$	2.49		$	1.17		$	0.66
	-1	For the twelve months ended December 31, 2013, the Company has excluded 10 stock options as their inclusion would be anti-dilutive. For the twelve months ended December 31, 2012, all potential common shares are excluded as they are anti-dilutive to the net loss from continuing operations.

Employee_Benefit_Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
EMPLOYEE BENEFIT PLANS	EMPLOYEE BENEFIT PLANS
	We offer medical, dental, vision and life insurance benefits to those employees who have completed their 90-day introductory period. Employees who have completed six months of service are eligible for an educational assistance program and to participate in the 401(k) plan, and employees who have completed one year of service are provided with long-term disability coverage. Additionally, we offer employees an opportunity to purchase a variety of supplemental benefits for their own account at no expense to the Company.
	We sponsor a defined contribution plan pursuant to Section 401(k) of the Code, whereby eligible employees may elect to contribute up to 50% of their gross wages. After one year of service, we match such contributions at a rate of 25% up to a maximum participant contribution of 6% of wages. We recorded expenses relating to this plan of approximately $170,000, $153,000 and $143,000 for the years ended December 31, 2014, 2013 and 2012, respectively.
	Supplemental Executive Retirement Plan
	Our Supplemental Executive Retirement Plan (the "SERP") was adopted by the Board of Directors on January 1, 1997. This Plan was implemented to provide competitive retirement benefits for officers and to act as a retention incentive. This non-qualified, unfunded, defined contribution plan extends to certain named officers nominated by the Chief Executive Officer and approved by the Executive Compensation Committee of the Board. The SERP provides for us to make a contribution accrual to the account of each of the participating officers at the end of each plan year. In January 2007, the Executive Compensation Committee revised the annual contribution accruals such that the accounts of participants not vested as of January 1, 2007 would no longer receive annual contribution accruals, however their accounts will continue to accrue interest. The accrual amount is a percentage of eligible earnings (including base salary and cash payments under the Annual Incentive Plan) that is set by the Executive Compensation Committee. Contribution accruals will not be taxable to the participant, other than social security and federal unemployment taxes once vested, until distribution. The account balances accrue interest each year at a rate determined by the Executive Compensation Committee to approximate the Company's weighted average cost of capital.
	The following table summarizes the changes in SERP balances for the years ended December 31:
	(In thousands)	2014		2013		2012
	Balance at beginning of period	$	2,520	$	2,283	$	2,067
	Service cost	80		81		77
	Interest cost	174		156		139
	Balance at end of period	$	2,774	$	2,520	$	2,283

Equity_Based_Award_Plans

Equity Based Award Plans	12 Months Ended
	Dec. 31, 2014
Share-based Compensation [Abstract]
EQUITY BASED AWARD PLANS	EQUITY BASED AWARD PLANS
	On May 4, 2011, our shareholders approved the Associated Estates Realty Corporation 2011 Equity-Based Award Plan (the "2011 Plan"), which had been adopted by our Board of Directors (the "Board") on February 23, 2011, subject to shareholder approval.
	A total of 1,726,608 common shares were made available for awards under the 2011 Plan, which included 1,500,000 newly authorized common shares and 226,608 common shares that remained available for awards under our 2008 Equity-Based Award Plan (the "2008 Plan") and our 2001 Equity Incentive Plan (the "2001 Plan"), both of which were approved by our shareholders. The 2011 Plan provided for the grant to our officers, other employees and directors of options to purchase our common shares, rights to receive the appreciation in value of common shares, awards of common shares subject to vesting and restrictions on transfer, awards of common shares issuable in the future upon satisfaction of certain conditions and other awards based on common shares. On February 25, 2014, the Board adopted The Associated Estates Realty Corporation Amended and Restated 2011 Equity-Based Award Plan (the “Restated Equity Plan”) to increase the number of shares reserved and available under the 2011 Plan. The details of the Restated Equity Plan are consistent with the 2011 Plan, except to increase the shares available for future Awards by 2,700,000 shares, and increase the individual annual Award limit of Stock Options and Share Appreciation Rights to 500,000. At December 31, 2014, we had 3,221,120 common shares available for awards under the Restated Equity Plan.
	Index
	Our 2001 and 2008 Plans were discontinued in May 2011 in conjunction with the shareholder approval of our 2011 Plan. Additionally, our Equity-Based Incentive Compensation Plan (the "Omnibus Plan") expired on February 20, 2005. Outstanding stock options awarded under these plans will remain in effect according to their original terms and conditions. Options were granted with per share exercise prices not less than fair market value at the date of grant and must be exercised within ten years thereof. Options outstanding and exercisable at December 31, 2014, were as follows:
		Options			Options
		Outstanding			Exercisable
	2011 Plan	61,286			19,620
	2001 Plan	299,090			299,090
		360,376			318,710
	During 2014, 2013 and 2012, our share-based compensation awards consisted primarily of restricted shares. We award share-based compensation to our officers and employees as a performance incentive and to align individual goals with those of the Company. Certain of our share-based awards require only continued service with the Company to vest. These awards vest either at the end of the specified service period or in equal increments during the service period on each anniversary of the grant date. We recognize compensation cost on these awards on a straight-line basis. In addition to awards containing only service conditions, we issue certain awards in which the number of shares that will ultimately vest is dependent upon the achievement of specified performance goals and/or market conditions. Compensation cost for awards with performance conditions is recognized based on our best estimate of the number of shares that will vest. Compensation cost for awards dependent upon market conditions is recognized based on the estimated fair market value of the award on the date granted, as described below, and the vesting period. We estimate the amount of expected forfeitures when calculating compensation costs. The forfeiture rates we use were calculated based on our historical forfeiture activity, adjusted for activity that we believe is not representative of expected future activity. During the years ended December 31, 2014, 2013 and 2012, we recognized share-based compensation cost in "General and administrative expense" of $3.8 million, $4.6 million and $3.7 million, respectively. Additionally, during the years ended December 31, 2014, 2013 and 2012, we capitalized $450,000, $400,000 and $200,000 of share-based compensation related to time incurred on development projects, respectively. See Note 2 for additional information related to capitalized payroll.
	Restricted Shares. Restricted shares generally have the same rights as our common shares, except for transfer restrictions and forfeiture provisions. Cash distributions paid during the period of restriction on shares that are expected to vest are recorded as a charge to "Accumulated distributions in excess of accumulated net income." Cash distributions paid during the period of restriction on shares that are expected to be forfeited are recorded as a charge to expense.
	We have two compensation plans under which our officers and directors may elect to defer the receipt of restricted shares. These plans are more fully discussed in Note 18. 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 or 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.
	Index
	The following table represents restricted share and DRSU activity for the year ended December 31, 2014:
					Weighted			Weighted
		Number of			Average			Average
		Restricted			Grant-Date		Number of	Grant-Date
		Shares			Fair Value		DRSUs	Fair Value
	Nonvested at beginning of period	735,184			$	10.52	34,797	$	17.15
	Granted	161,267			$	16.11	45,365	$	17.06
	Vested	175,287			$	16.39	26,603	$	17.38
	Forfeited	18,304			$	11.39	8,194	$	16.38
	Nonvested at end of period	702,860			$	10.31	45,365	$	17.06
	The weighted average grant-date fair value of restricted shares granted during the years ended December 31, 2013 and 2012 was $10.44 and $16.48, respectively. The total fair value of restricted shares vested during the years ended December 31, 2014, 2013 and 2012 was $2.9 million, $7.6 million and $2.9 million, respectively. The total fair value of DRSUs vested during the years ended December 31, 2014, 2013 and 2012 was $460,000, $669,000 and $715,000, respectively, recognized as "Paid-in-capital." At December 31, 2014, there was a total of $4.7 million of unrecognized compensation cost related to non-vested restricted share awards and DRSUs that we expect to recognize over a weighted average period of 1.8 years.
	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.
	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
	Index
	Stock Options. We use the Black-Scholes option pricing model to estimate the fair value of stock options awarded. There were no options awarded in 2014 and 2013, and 125,000 options awarded in 2012. The weighted average Black-Scholes assumptions and fair value for 2012 were as follows:
	Expected volatility	33.9		%
	Risk-free interest rate	1.3		%
	Expected life of options	7 years
	Dividend yield	4.7		%
	Grant-date fair value	$	2.97
	The expected volatility was based upon a 50/50 blend of historical and implied volatility. The historical volatility based upon changes in the weekly closing prices of our shares over a period equal to the expected life of the options 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 both closest to the expected life and the exercise price of the options. The longest terms of such options over the trailing month averaged 7.1 months. The risk-free interest rate used was the yield from U.S. Treasury zero-coupon bonds on the date of the grant with a maturity equal to the expected life of the options. The expected life was derived using our historical experience for similar awards. The dividend yield was derived using our annual dividend rate as a percentage of the price of our shares on the date of grant.
	The following table represents stock option activity for the year ended December 31, 2014:
							Weighted-
		Number of			Weighted-		Average
		Stock			Average		Remaining
		Options			Exercise Price		Contract Life
	Outstanding at beginning of period	510,020			$	11.47
	Exercised	80,930			$	9.07
	Forfeited	68,714			$	15.2
	Outstanding at end of period	360,376			$	11.29	2.1
	Exercisable at end of period	318,710			$	10.77	1.4
	The aggregate intrinsic value of stock options outstanding and stock options exercisable at December 31, 2014 and 2013 was $4.0 million and $2.4 million, respectively.

DirectorExecutive_Compensation

Director/Executive Compensation	12 Months Ended
	Dec. 31, 2014
Director Executive Compensation [Abstract]
DIRECTOR/EXECUTIVE COMPENSATION	DIRECTOR/EXECUTIVE COMPENSATION
	Elective Deferred Compensation Program
	The Associated Estates Realty Corporation Elective Deferred Compensation Program is an unfunded, non-qualified deferred compensation program that is subject to the provisions of Section 409A of the Internal Revenue Code, which strictly regulates the timing of elections and payment. Eligibility under the plan shall be determined by the Executive Compensation Committee or its designee, and at December 31, 2014, each of our appointed and/or elected officers was eligible.
	This plan permits deferral of up to 90.0% of base salary and up to 100% of any incentive payment. An individual bookkeeping account will be maintained for each participant. Participants are provided a number of measurement funds from which they may select to determine earnings, which may be, but are not required to be, the same as those offered under our 401(k) savings plan. Deferrals of base salary and incentive payments (other than restricted shares, discussed below) are fully vested.
	Index
	The plan also permits the deferral of the receipt of restricted shares granted under the 2011 Plan, which also will be reflected in a separate bookkeeping account for each individual as share equivalent units. Dividend credits shall be made to such account in the form of share equivalent units. Distribution of amounts reflected by such share equivalents will be made in the form of shares. The vesting of share equivalent units (together with associated dividend credits for performance based awards) occurs on the same schedule as the restricted shares that had been deferred.
	The plan allows for in-service and separation sub-accounts to permit election of distribution at either a specified date or following separation. Payment of each deferral under the plan will be made in the form specified in the participant's election, and may be in the form of a lump sum or annual installment payments over a period not to exceed four years. Payment of each deferral under the plan will be made on account of separation from service, death, or disability, or at a time specified by the participant, within the parameters set forth in the plan. Re-deferral elections are permitted within the parameters set forth in the plan. Accounts will be distributed upon a change of control, and distribution due to unforeseen financial hardship is also possible.
	At December 31, 2014, there were 323,105 share equivalent units deferred under this plan, of which 238,535 represent the deferred share awards and 84,750 of which represent dividend units. At December 31, 2013, there were 307,207 share equivalent units deferred under this plan, of which 235,786 represent the deferred share awards and 71,421 of which represent dividend units. Additionally, 5,407 shares were distributed from this plan during 2014.
	Directors' Deferred Compensation Plan
	The Directors' Deferred Compensation Plan allows persons serving as non-employee Directors the option of deferring receipt of compensation otherwise payable to them for their services as Directors, and creates an opportunity for appreciation of the amount deferred based upon the performance of our common shares.
	Prior to January 1 of each year, any eligible Director may elect to defer all or a portion of the fees otherwise payable to that Director for that year, and such amount will be credited to a deferral account maintained on behalf of the Director. Fees for each period are converted to "share units" and credited to the deferral account as they are earned. This plan also permits the deferral of the receipt of restricted shares granted, which also will be reflected in a separate bookkeeping account for each individual as share equivalent units.
	Each deferral account is increased when we pay a dividend on our common shares by the number of share units that represent the dividend paid per share multiplied by the number of share units in the account on the date of record for the related dividend payment. Share units representing deferred fees and dividend units are vested at all times. Share units representing deferred restricted shares vest on the same schedule as the restricted shares that were deferred. In December 2009 and effective on January 1, 2010, this plan was modified such that all distributions from the plan will be in the form of our common shares instead of cash. As a result, the value of the deferred compensation is included in "Paid-in capital" and is not adjusted based upon subsequent changes in the price of our common shares. At December 31, 2014, there were 318,075 share equivalent units under this plan, of which 95,060 units represent the deferral of cash fees earned, 129,116 represents the deferral of shares and 93,898 units represent the deferral of dividends. Distributions of $45,000 and $45,000 were made in cash from this plan during 2013 and 2012, respectively. Additionally, 8,789, 20,651 and 59,988 shares were distributed from this plan during 2014, 2013 and 2012, respectively.
	Index
	Executive Compensation and Employment Agreements
	On December 31, 2012, we entered into the Second Amended and Restated Employment Agreement, dated December 31, 2012, with Mr. Jeffrey I. Friedman, the Company's Chairman, President and CEO (the “Amended Agreement”).
	The Amended Agreement, effective as of January 1, 2013, removes the prior “evergreen” term and replaces it with a five year term, unless terminated prior to that time by reason of Mr. Friedman's death, permanent disability or retirement or by the Company for “cause” or without “cause” (as such terms are defined in the Amended Agreement). The Amended Agreement eliminates the tax gross-up provisions relating to Internal Revenue Code Section 280G that were contained in Mr. Friedman's prior employment agreement. The Amended Agreement also eliminates the so-called “single trigger” provision that allowed Mr. Friedman to voluntarily terminate his employment with the Company following a change in control and receive severance benefits. The Amended Agreement also includes non-competition and non-solicitation provisions that apply during the term of the agreement and for a period of three years following termination of the agreement.
	Additionally, we have severance arrangements with certain other executive officers.
	Annual Incentive Plan
	In February of each year, the Executive Compensation Committee (the "Committee") approves the terms of the Annual Incentive Plan for Officers. Annual incentives emphasize pay for performance and serve as a key means of driving current objectives and priorities. The Committee determines specific compensation levels for the five most highly compensated officers ("Officers"), which includes our five "Named Executive Officers." Officers are rewarded for accomplishing our short-term financial and business unit objectives. Annual incentive opportunities for the Officers were linked to same property NOI, as defined, business unit objectives and individual performance. The Officers earned annual incentives of approximately $1.8 million, $2.0 million and $1.9 million in cash in 2014, 2013 and 2012, respectively.
	Long-Term Incentive Plan
	Our Long-Term Incentive Plan ("LTIP") is intended to create a stronger link to shareholder returns, reward long-term performance and foster retention of the executives. The Committee determines specific compensation levels for our Officers. Each Officer has threshold, target and maximum award opportunities established that are expressed as a percentage of base salary. The framework of the LTIP includes a single-year and multi-year component.
	Single-year component. Objectives under the single-year LTIP are established annually at the beginning of the year and evaluated at the conclusion of the year. If one or all of the objectives is met, a grant of restricted shares will be issued. One-third of the issued shares will vest immediately and the remaining two-thirds will vest in equal, annual installments. Restricted shares, if issued, have voting rights and dividends will be paid on them during the restricted period.
	In February of each year, the Committee approves the terms of that year's single-year component of the LTIP. This component focused primarily on interest coverage and fixed charge coverage financial ratios and same property NOI. Officers earned approximately $1.6 million, $1.8 million and $2.1 million under the single-year LTIP in 2014, 2013 and 2012, respectively.
	Multi-year component. The multi-year component focuses on performance over a three-year measurement period. Grants under the multi-year component are issued and metrics and objectives are established every three years. Any shares that are earned at the end of the measurement period will vest one year from the end of such measurement period. Restricted shares have voting rights and dividends accrue and earn interest at a rate determined by the Executive Compensation Committee during the restricted period. Only the dividends and accrued interest attributable to shares that vest will be paid when such shares vest.
	Index
	In February 2013, the Committee approved the terms of the 2013 multi-year component. This component focuses on absolute and relative cumulative total shareholder return over the three-year period ended December 31, 2015, and continued employment with the Company through December 31, 2016. Total shareholder return threshold, target and maximum objectives were established and a grant of restricted shares was issued to the Officers in February 2013 with an intrinsic value of $7.1 million. Shares granted under this component, if any, are eligible for vesting on December 31, 2016, which is the end of the service period.
	In February 2010, the Committee approved the terms of the 2010 multi-year component. This component focused on absolute and relative cumulative total shareholder return over the three-year period ending December 31, 2012, and continued employment with the Company through December 31, 2013. Total shareholder return threshold, target and maximum objectives were established and a grant of restricted shares was issued to the Officers in February 2010 with an intrinsic value of $3.9 million. Based upon the performance for the three-year period ended December 31, 2012, shares having an intrinsic value of $3.3 million when granted vested on December 31, 2013, which was the end of the service period.

Subsequent_Events

Subsequent Events	12 Months Ended
	Dec. 31, 2014
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	SUBSEQUENT EVENTS
	Acquisition of Equity Interest. On February 3, 2015, we exercised our buy-sell option with respect to the 5th and Huntington partnership and acquired Lincoln's 50.0% interest for $8.4 million. This purchase increased our percentage ownership in the development to 100%.
	Debt. 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 December 31, 2014, 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 December 31, 2014, or an all-in rate of 3.15% per annum, through the maturity date of January 2020.
	Dividends. On January 30, 2015, we paid a dividend of $0.21 per common share to shareholders of record on December 30, 2014, which had been declared on December 3, 2014. The declaration and payment of future quarterly dividends remains subject to review by, and approval of, the Board of Directors.

Quarterly_Financial_Informatio

Quarterly Financial Information (Unaudited)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
QUARTERLY FINANCIAL INFORMATION (UNAUDITED)	QUARTERLY FINANCIAL INFORMATION (UNAUDITED)
		2014
		First		Second		Third		Fourth
	(In thousands, except per share data)	Quarter		Quarter		Quarter		Quarter
	Revenue	$	49,715	$	47,902	$	48,207	$	48,256
	Operating income	$	8,260	$	9,031	$	9,805	$	10,336
	Net income	$	42,273	$	62,348	$	3,418	$	36,672
	Net income attributable to AERC	$	42,273	$	62,348	$	3,418	$	36,672
	Basic earnings per common share	$	0.73	$	1.08	$	0.06	$	0.64
	Diluted earnings per common share	$	0.73	$	1.07	$	0.06	$	0.63
		2013
		First		Second		Third		Fourth
	(In thousands, except per share data)	Quarter		Quarter		Quarter		Quarter
	Revenue	$	42,856	$	43,484	$	46,069	$	49,070
	Operating income	$	7,550	$	8,322	$	8,963	$	9,795
	Net income	$	10,363	$	1,652	$	20,007	$	29,273
	Net income attributable to AERC	$	10,346	$	1,638	$	19,993	$	29,273
	Basic earnings per common share	$	0.21	$	0.03	$	0.4	$	0.51
	Diluted earnings per common share	$	0.2	$	0.03	$	0.4	$	0.51

Schedule_II_Valuation_and_Qual

Schedule II - Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2014
Valuation and Qualifying Accounts [Abstract]
Valuation and Qualifying Accounts - Schedule II
	SCHEDULE II
	ASSOCIATED ESTATES REALTY CORPORATION
	VALUATION AND QUALIFYING ACCOUNTS
	Column A		Column B		Column C				Column D			Column E
					ADDITIONS
	(In thousands)		Balance at		Charged to		Charged					Balance
			Beginning		Costs and		to Other					at End
	DESCRIPTION		of Period		Expenses (1)		Accounts		Deductions (2)			of Period
	Year ended December 31, 2014:
	Deducted from asset accounts:
	Allowance for doubtful accounts		$	78	$	1,657	$	—	$	(1,666	)	$	69
	Valuation allowance-deferred tax asset		6,632		38		—		—			6,670
	Year ended December 31, 2013:
	Deducted from asset accounts:
	Allowance for doubtful accounts		$	104	$	1,823	$	—	$	(1,849	)	$	78
	Valuation allowance-deferred tax asset		6,626		6		—		—			6,632
	Year ended December 31, 2012:
	Deducted from asset accounts:
	Allowance for doubtful accounts		$	141	$	1,991	$	—	$	(2,028	)	$	104
	Valuation allowance-deferred tax asset		5,970		656		—		—			6,626
	-1	Adjustments to the valuation allowance for deferred taxes are recorded to adjust deferred tax asset to net realizable value.
	-2	Includes the write-off of uncollectible balances, net of any subsequent recoveries received from tenants.

Schedule_III_Real_Estate_and_A

Schedule III - Real Estate and Accumulated Depreciation	12 Months Ended
	Dec. 31, 2014
SEC Schedule III, Real Estate and Accumulated Depreciation Disclosure [Abstract]
Real Estate and Accumulated Depreciation Disclosure [Text Block]
	SCHEDULE III
	ASSOCIATED ESTATES REALTY CORPORATION
	REAL ESTATE AND ACCUMULATED DEPRECIATION
	December 31, 2014
							Initial Cost to Company
														Costs
	(In thousands)													Capitalized
			Dates Acquired/		Depreciable						Buildings &			Subsequent
	Property		Constructed		Lives - Years		Land				Improvements			to Acquisition
	PROPERTIES
	NORTHEAST OHIO
	Mallard's Crossing		February, 1995		30-May		$	941			$	8,499		$	3,141
	The Residence at Barrington		September, 1995		30-May		2,357				21,986			2,114
	Village at Avon		June, 1998		30-May		2,145				21,704			3,134
	Village of Western Reserve		August, 1996		30-May		691				6,866			860
	Westchester Townhomes		November, 1989		15-May		693				5,686			1,293
	Westlake Seven		October, 1995		30-May		559				332			349
	Williamsburg Townhomes		February, 1994		30-May		844				12,787			4,083
	CENTRAL OHIO
	Bedford Commons		December, 1994		30-May		929				5,751			1,124
	Heathermoor		August, 1994		30-May		1,796				8,535			2,194
	Kensington Grove		July, 1995		30-May		533				4,600			936
	Lake Forest		July, 1994		30-May		824				6,135			1,124
	Perimeter Lakes		September, 1996		30-May		1,265				8,647			1,574
	Saw Mill Village		April, 1997		30-May		2,548				17,218			4,664
	Sterling Park		August, 1994		30-May		646				3,919			725
	The Residence at Christopher Wren		March, 1994		30-May		1,560				13,754			4,000
	Wyndemere Land		March, 1997		—		200				—			—
	SOUTHEAST MICHIGAN
	Arbor Landings		June, 1999		30-May		1,129				10,403			11,141
	Clinton Place		August, 1997		30-May		1,219				9,478			2,486
	Georgetown Park		June, 1999		30-May		1,778				12,141			14,270
	Oaks at Hampton		August, 1995		30-May		3,026				27,204			5,023
	Spring Valley		October, 1997		30-May		1,433				13,461			2,156
	WESTERN MICHIGAN
	Landings at the Preserve		September, 1995		30-May		1,081				7,190			1,571
	Summer Ridge		April, 1996		30-May		1,251				11,194			2,827
	Index
	SCHEDULE III
	ASSOCIATED ESTATES REALTY CORPORATION
	REAL ESTATE AND ACCUMULATED DEPRECIATION
	December 31, 2014
	(In thousands)		Gross Amount at Which Carried at December 31, 2014
							Buildings &							Accumulated			Encumbrances		Maturity
	Property		Land				Improvements				Total			Depreciation			-1		Date
	PROPERTIES
	NORTHEAST OHIO
	Mallard's Crossing		$	941			$	11,640			$	12,581		$	7,434		$	—	—
	The Residence at Barrington		2,355				24,100				26,455			13,305			—		—
	Village at Avon		2,145				24,838				26,983			12,139			19,560		December, 2015
	Village of Western Reserve		691				7,726				8,417			4,069			—		—
	Westchester Townhomes		693				6,979				7,672			5,860			—		—
	Westlake Seven		559				1,240				1,799			1,166			—		—
	Williamsburg Townhomes		844				16,870				17,714			11,215			—		—
	CENTRAL OHIO
	Bedford Commons		929				6,875				7,804			4,447			—		—
	Heathermoor		1,796				10,729				12,525			7,175			—		—
	Kensington Grove		533				5,536				6,069			3,386			—		—
	Lake Forest		824				7,259				8,083			4,765			—		—
	Perimeter Lakes		1,265				10,221				11,486			6,340			—		—
	Saw Mill Village		2,548				21,882				24,430			12,957			15,930		April, 2016
	Sterling Park		646				4,644				5,290			2,978			—		—
	The Residence at
Christopher Wren		1,560				17,754				19,314			11,751			—		—
Wyndemere Land		200				—				200			—			—		—
SOUTHEAST MICHIGAN
Arbor Landings		1,682				20,991				22,673			12,279			—		—
Clinton Place		1,219				11,964				13,183			6,981			—		—
Georgetown Park		2,128				26,061				28,189			16,148			—		—
Oaks at Hampton		3,026				32,227				35,253			20,964			—		—
Spring Valley		1,433				15,617				17,050			8,776			—		—
WESTERN MICHIGAN
Landings at the Preserve		1,143				8,699				9,842			5,392			—		—
Summer Ridge		1,251				14,021				15,272			8,398			—		—
Index
SCHEDULE III
ASSOCIATED ESTATES REALTY CORPORATION
REAL ESTATE AND ACCUMULATED DEPRECIATION
December 31, 2014
						Initial Cost to Company
												Costs
(In thousands)												Capitalized
		Dates Acquired/		Depreciable					Buildings &			Subsequent
Property		Constructed		Lives - Years		Land			Improvements			to Acquisition
PROPERTIES
SOUTHEAST FLORIDA
Doral West (2)		July, 2013		30-May		12,060			79,513			3,464
Vista Lago (2)		March, 2005		30-May		4,012			35,954			688
Waterstone at Wellington (2)		June, 2011		30-May		5,948			25,456			773
Windsor Pines		October, 1998		30-May		4,834			28,795			1,843
ATLANTA
Cambridge at Buckhead (2)		October, 2005		30-May		6,166			16,730			1,142
Morgan Place		July, 1998		30-May		3,292			9,159			1,710
METRO DC
7001 Arlington at Bethesda (3)		—		—		12,650			—			—
Dwell Vienna Metro (2)		August, 2011		30-May		11,241			67,130			277
INDIANAPOLIS
Center Point		August, 1997		30-May		1,508			22,861			2,593
Residence at White River		February, 1997		30-May		1,064			11,631			2,579
Steeplechase at Shiloh		July, 1998		30-May		2,261			16,257			1,237
RALEIGH-DURHAM
Lofts at Weston Lakeside (2)		November, 2013		30-May		4,112			33,105			26
Southpoint Village (2)		July, 2012		30-May		3,307			29,661			163
St. Mary's Square (2)		November, 2013		30-May		3,065			23,481			29
The Apartments at the Arboretum (2)		May, 2012		30-May		4,008			33,411			565
The Park at Crossroads (2)		August, 2012		30-May		5,520			31,391			800
CHARLOTTE
Alpha Mill Phase I and Phase II (2)		June, 2014		30-May		8,140			36,044			119
The Apartments at Blakeney (2)		October, 2013		30-May		5,430			46,013			216
Index
SCHEDULE III
ASSOCIATED ESTATES REALTY CORPORATION
REAL ESTATE AND ACCUMULATED DEPRECIATION
December 31, 2014
(In thousands)		Gross Amount at Which Carried at December 31, 2014
					Buildings &						Accumulated		Encumbrances		Maturity
Property		Land			Improvements			Total			Depreciation		-1		Date
PROPERTIES
SOUTHEAST FLORIDA
Doral West (2)		12,060			82,977			95,037			5,062		—		—
Vista Lago (2)		4,012			36,642			40,654			13,041		—		—
Waterstone at Wellington (2)		5,948			26,229			32,177			3,781		—		—
Windsor Pines		4,834			30,638			35,472			16,822		—		—
ATLANTA
Cambridge at Buckhead (2)		6,166			17,872			24,038			6,015		—		—
Morgan Place		3,292			10,869			14,161			5,790		—		—
METRO DC
7001 Arlington at Bethesda (3)		12,650			—			12,650			—		16,673		October, 2016
Dwell Vienna Metro (2)		11,241			67,407			78,648			8,593		41,167		June, 2022
INDIANAPOLIS
Center Point		1,470			25,492			26,962			14,772		—		—
Residence at White River		1,064			14,210			15,274			8,192		—		—
Steeplechase at Shiloh		2,261			17,494			19,755			9,501		—		—
RALEIGH-DURHAM
Lofts at Weston Lakeside (2)		4,112			33,131			37,243			1,591		—		—
Southpoint Village (2)		3,307			29,824			33,131			2,955		—		—
St. Mary's Square (2)		3,065			23,510			26,575			1,049		—		—
The Apartments at
the Arboretum (2)		4,008			33,976			37,984			3,589		—		—
The Park at Crossroads (2)		5,520			32,191			37,711			3,414		25,246		August, 2016
CHARLOTTE
Alpha Mill Phase I and Phase II (2)		8,140			36,163			44,303			769		—		—
The Apartments at Blakeney (2)		5,430			46,229			51,659			2,457		27,560		January, 2022
Index
SCHEDULE III
ASSOCIATED ESTATES REALTY CORPORATION
REAL ESTATE AND ACCUMULATED DEPRECIATION
December 31, 2014
						Initial Cost to Company
													Costs
(In thousands)													Capitalized
		Dates Acquired/		Depreciable						Buildings &			Subsequent
Property		Constructed		Lives - Years		Land				Improvements			to Acquisition
PROPERTIES
NORTHERN VIRGINIA
Ashborough (2)		September, 2010		30-May		20,136				65,885			802
Riverside Station (2)		May, 2010		30-May		13,680				38,708			664
Westwind Farms (2)		December, 2010		30-May		18,265				67,098			802
SOUTHEAST VIRGINIA
River Forest (2)		April, 2008		30-May		4,655				25,758			7,314
The Alexander at Ghent (2)		June, 2007		30-May		4,368				43,263			1,275
The Belvedere (2)		April, 2008		30-May		6,044				35,353			572
CALIFORNIA
Desmond's Tower (2) (4)		May, 2012		14-30		7,390				10,615			—
The Desmond on Wilshire (3)		May, 2012		—		17,491				—			—
Warner Center (5)		November, 2014		—		16,139				—			—
DALLAS
Cantabria at Turtle Creek (3)		—		—		6,983				—			33,242
Rienzi at Turtle Creek (2)		September, 2013		30-May		3,911				43,680			302
San Raphael (2)		October, 2010		30-May		3,777				15,795			1,278
San Raphael Phase II		February, 2014		30-May		733				12,263			—
The Brixton (2)		October, 2011		30-May		2,867				17,638			803
21 Forty Medical District (2)		July, 2012		30-May		5,413				44,823			561
						$	259,918			$	1,204,961		136,628
MISCELLANEOUS
Improvements		November, 1993		30-Oct									7,142
													$	143,770
Index
SCHEDULE III
ASSOCIATED ESTATES REALTY CORPORATION
REAL ESTATE AND ACCUMULATED DEPRECIATION
December 31, 2014
(In thousands)		Gross Amount at Which Carried at December 31, 2014
						Buildings &							Accumulated			Encumbrances		Maturity
Property		Land				Improvements				Total			Depreciation			-1		Date
PROPERTIES
NORTHERN VIRGINIA
Ashborough (2)		20,136				66,687				86,823			10,967			47,591		May, 2018
Riverside Station (2)		13,680				39,372				53,052			6,820			34,855		September, 2020
Westwind Farms (2)		18,265				67,900				86,165			10,684			—		—
SOUTHEAST VIRGINIA
River Forest (2)		4,645				33,083				37,728			8,018			—		—
The Alexander at Ghent (2)		4,367				44,538				48,905			12,515			—		—
The Belvedere (2)		6,044				35,925				41,969			8,898			—		—
CALIFORNIA
Desmond's Tower (2) (4)		7,390				10,615				18,005			1,171			—		—
The Desmond on Wilshire (3)		17,491				—				17,491			—			—		—
Warner Center (5)		16,139				—				16,139			—			—		—
DALLAS
Cantabria at Turtle Creek (3)		6,983				33,242				40,225			317			32,006		October, 2016
Rienzi at Turtle Creek (2)		3,911				43,982				47,893			2,084			—		—
San Raphael (2)		3,777				17,073				20,850			2,967			—		—
San Raphael Phase II		733				12,263				12,996			840			—		—
The Brixton (2)		2,867				18,441				21,308			2,432			12,025		June, 2019
21 Forty Medical District (2)		5,413				45,384				50,797			4,450			—		—
		260,832				1,341,232				1,602,064			367,481			$	272,613
MISCELLANEOUS		945				5,638				6,583			3,079
Land, Building and
Improvements		$	261,777			$	1,346,870			1,608,647			370,560
Furniture, Fixtures and
Equipment										41,609			26,650
Construction in Progress										73,581			—
GRAND TOTALS										$	1,723,837		$	397,210
-1	Encumbrances include mortgage debt collateralized by the real estate assets.
-2	For acquisitions initiated after June 30, 2001, intangible assets such as in place leases were recognized upon the acquisition of these properties and are not included in the initial costs or historical costs shown.
-3	Currently under development.
-4	Commercial building containing 78,800 total square feet.
-5	Future development project.
Index
SCHEDULE III
ASSOCIATED ESTATES REALTY CORPORATION
REAL ESTATE AND ACCUMULATED DEPRECIATION
31-Dec-14
The aggregate cost for federal income tax purposes was approximately $1.5 billion at December 31, 2014.
The changes in total real estate assets for the years ended December 31, 2014, 2013 and 2012 are as follows:
(In thousands)	2014				2013				2012
Balance, beginning of period	$	1,751,519			$	1,511,647			$	1,345,439
Disposal of fixed assets	(179,655		)		(124,684		)		(75,770		)
New acquisition properties	45,075				257,683				178,864
Improvements	106,898				106,873				63,114
Balance, end of period	$	1,723,837			$	1,751,519			$	1,511,647
The changes in accumulated depreciation for the years ended December 31, 2014, 2013 and 2012 are as follows:
(In thousands)	2014				2013				2012
Balance, beginning of period	$	386,841			$	371,730			$	358,605
Disposal of fixed assets	(49,905		)		(40,844		)		(37,531		)
Depreciation for period	60,274				55,955				50,656
Balance, end of period	$	397,210			$	386,841			$	371,730

Significant_Accounting_Policie1

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
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.
	The accompanying consolidated financial statements include the accounts of all subsidiaries, any REIT subsidiaries (which are taxed as Taxable REIT Subsidiaries ("TRS") under the REIT Modernization Act implemented in 1999) and a partnership in which we were a 98.1% and 97.0% partner at December 31, 2014 and 2013, respectively, that owns a property in Bethesda, Maryland.
	Limited partnership interests held by others in the partnership in which we are a 98.1% and 97.0% partner at December 31, 2014 and 2013, respectively, are reflected as "Noncontrolling interest" in the Consolidated Balance Sheets. Capital contributions, distributions and profits and losses are allocated to noncontrolling interests in accordance with the terms of the partnership agreements, respectively. All significant intercompany balances and transactions have been eliminated in consolidation.
	We own 100% of the common stock of all taxable REIT subsidiaries included in our consolidated financial statements.
	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 twelve months ended December 31, 2014, substantially all of our consolidated revenue was provided by our multifamily properties. We have determined that as of December 31, 2014, we have one reportable segment which is multifamily properties.
Use of Estimates	Use of Estimates
	The preparation of the consolidated financial statements in accordance with accounting principles generally accepted in the United States of America ("GAAP") requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the consolidated financial statements and reported amounts of revenues and expenses during the reporting periods. Actual results could differ from these estimates.
Cash Equivalents	Cash Equivalents
	Highly liquid investments with an original maturity of three months or less when purchased are considered to be cash equivalents.
Real Estate Capitalization Policies and Depreciation	Real Estate Capitalization Policies and Depreciation
	Real estate assets are stated at cost less accumulated depreciation. Depreciation is provided on a straight-line basis over the estimated useful lives of the assets as follows:
	Buildings and improvements	5 - 30 years
	Furniture, fixtures and equipment	5 - 10 years
	We capitalize replacements and improvements, such as HVAC equipment, structural replacements, windows, appliances, flooring, carpeting and kitchen/bath replacements and renovations. Ordinary repairs and maintenance, such as unit cleaning, painting and appliance repairs, are expensed when incurred.
	We allocate the purchase price of acquired properties to net tangible and identified intangible assets acquired based on their fair values. In making estimates of fair values for purposes of allocating purchase price, we utilize a number of sources, including analysis provided by an advisor, independent appraisals that may be obtained in connection with the acquisition or financing of the respective property, our analysis of recently acquired and existing comparable properties in our portfolio and other market data. The intangible assets are amortized over the remaining lease terms, which is 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. Transaction costs associated with the acquisition of operating properties are expensed as incurred in "Costs associated with acquisitions."
	Pre-development costs incurred in pursuing future development which is not yet considered probable are expensed as incurred. While what is deemed to be probable can vary from project to project, some examples include the point in time in which a letter of intent has been issued or accepted, the commencement of due diligence or obtainment of approval from the Board of Directors, when necessary. In addition, if a development project becomes no longer probable, any capitalized pre-development costs are written off to expense in "General and administrative."
	Index
	For properties under development, we capitalize interest costs on funds used in construction, real estate taxes and insurance from the commencement of development activity, where we are undergoing activities necessary to get the property ready for its intended use and expenditures for the asset have been made, through the time the property is substantially complete and ready for leasing (i.e., certificate of occupancy has been obtained). For properties under development accounted for under the equity method, we capitalize interest costs on our investment from the commencement of development activity through the time the venture is substantially complete and commenced planned principal operations. We also capitalize internal costs related to our consolidated and equity method ventures, which are primarily payroll, but may also include costs such as travel, lodging and temporary construction facilities that are directly attributable to the construction of a property or asset.
	Certain costs associated with the lease-up of development projects, such as signs and "grand openings" are capitalized and amortized over the estimated life of average tenant relationships, which are approximately 12 months. All other internal costs associated with the lease up of development properties are expensed as incurred. Revenue from incidental operations for properties under development is recognized as a reduction of capitalized project costs. Development assets are fully transfered from construction in progress to fixed assets in the period in which substantially all units have come on-line and are held available for occupancy.
	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, as defined above. Total capitalized interest during 2014, 2013 and 2012 was $4.8 million, $3.6 million and $1.5 million, respectively. Total capitalized payroll costs during 2014, 2013 and 2012 were $3.5 million, $2.8 million and $2.4 million, respectively.
Classification of Fixed Asset Additions	Classification of Fixed Asset Additions
	We define recurring fixed asset additions to a property as capital expenditures made to replace worn out assets to maintain the property's value. Revenue enhancing/non-recurring fixed asset additions are defined as capital expenditures that increase the value of the property and enable us to increase rents. Acquisition/development fixed asset additions are defined as capital expenditures for the purchase or construction of new properties to be added to our portfolio, or fixed asset additions identified at the time of purchase that are not made until subsequent periods.
Development Costs	Development Costs Reported on the Consolidated Statements of Operations and Comprehensive Income
	Development costs represent costs incurred related to our in-house development and construction division that do not quality for capitalization and are expensed as incurred.
Disposition of Real Estate and Investments in Unconsolidated Entities	Disposition of Real Estate and Investments in Unconsolidated Entities
	Sales of real estate include the sale of land, operating properties and investments in unconsolidated entities which are in-substance real estate. We follow Accounting Standards Codification No. 360-20, Property, Plant and Equipment - Real Estate Sales, in determining whether our sales of real estate meet the criteria for full profit accrual method. The results of operations and gains related to the sale of operating properties for the year ended December 31, 2014 are reported in income from continuing operations in the accompanying Consolidated Statements of Operations and Comprehensive Income. Prior to adoption of ASU 2014-08, and in all prior periods presented, these results were reported in "Income from discontinued operations," in the accompanying Consolidated Statements of Operations and Comprehensive Income. Furthermore, the results of properties classified as held for sale are now reported in income from continuing operations.
Impairment of Long-Lived Assets, Development and Investments in Unconsolidated Entities	Impairment of Long-Lived Assets, Development and Investments in Unconsolidated Entities
	Our held for investment real estate assets are assessed for impairment if current events or circumstances, such as significant adverse changes in general market conditions, decreases in property net operating income, or reductions in expected future cash flows, indicate that the carrying value (cost less accumulated depreciation) may not be recoverable. Factors we consider in evaluating impairment of real estate assets held for investment include estimated future growth rates, capitalization rates, occupancy assumptions, current expectations regarding the holding period for the individual assets and external data to the extent available. Real estate assets held for investment are not considered impaired if the undiscounted, estimated future cash flows of the asset (both the annual estimated cash flow from future operations and the estimated cash flow from the theoretical sale of the asset) over its estimated holding period are in excess of the asset's net book value at the measurement date. If the carrying value of any real estate asset held for investment is not recoverable, an impairment loss is recorded to reduce the carrying value of the asset to its fair value. Our development properties are assessed for impairment as well, in which we consider the projected future cash flows from the development properties' planned use upon project completion in relation to their current carrying value plus the projected costs to complete. Our investments in unconsolidated entities are assessed for other than temporary impairment, in which we consider the fair value of the investment in relation to its current carrying value. No impairments were recorded for the years ended December 31, 2014, 2013 and 2012.
Real Estate Held for Sale	Real Estate Held for Sale
	We periodically classify real estate assets as held for sale. We consider real estate assets to be held for sale when a sales contract is executed with no substantive contingencies in place, inclusive of the completion of the prospective buyer's due diligence period. Assets that are classified as held for sale are recorded at the lower of their carrying amount or fair value less cost to sell. Upon the classification of a real estate asset as held for sale, we estimate its fair value less costs to sell. If the fair value less costs to sell is less than the carrying value, then we reduce the carrying value to the fair value less costs to sell. Subsequent to the classification of assets as held for sale, no further depreciation expense is recorded. There were no properties recorded as held for sale at December 31, 2014 and 2013.
Income Taxes	Income Taxes
	We have elected to be taxed as a REIT under the Internal Revenue Code of 1986 (the "Code"), as amended. As a REIT, we are entitled to a tax deduction for dividends paid to shareholders, thereby effectively subjecting the distributed net income to taxation at the shareholder level only, provided we distribute at least 90.0% of our taxable income and meet certain other qualifications. Our two REIT subsidiaries that have historically engaged in third party property and asset management and third party construction services, respectively, have elected to be treated as Taxable REIT Subsidiaries ("TRS") and operate as C-corporations under the Code. Accordingly, these TRS entities separately account for income taxes. Taxes are recorded for these two TRS subsidiaries to the extent they recognize net profits for both financial statement and income tax purposes. See Note 10 for further details.
Accounts Receivable	Accounts Receivable
	We make estimates of the amounts we believe will not be collected related to rents receivable. We analyze the accounts receivable aging balance using historical patterns and apply a reserve percentage based upon those historical patterns and current trends at the properties. At December 31, 2014 and 2013, rents receivable, net of a provision for uncollectible amounts of $69,000 and $78,000, respectively, aggregated $1.1 million and $1.2 million, respectively. Other accounts receivable are reviewed and reserved for on a case-by-case basis depending on the nature of the receivable and any current information related to the collectibility of the receivable.
Deferred Financing Costs	Deferred Financing Costs
	Costs incurred in obtaining long-term financing, included in "Other assets, net," are deferred and amortized over the life of the associated instrument using the effective interest method.
Goodwill	Goodwill
	Goodwill, included in "Other assets, net," is tested for impairment annually, or more frequently if events or changes in circumstances indicate that the carrying value may not be recoverable. See Note 5 for additional information related to intangible assets and goodwill.
Property Revenue Recognition	Property Revenue Recognition
	Our residential property leases are for terms of generally one year or less. Rental income is recognized on a straight-line basis over the term of the lease.
	Rent concessions, including any free rent incurred in connection with residential property leases, are amortized on a straight-line basis over the terms of the related leases (approximately one year) and are charged as a reduction of rental revenue.
Property Management and Construction Services Revenue Recognition	Property Management and Construction Services Revenue Recognition
	Property management fees are recognized when the related services are performed and the earnings process is complete. Construction services fees are recognized in accordance with the associated development agreements. See Note 6 for further detail related to construction service fees recognized to date.
Advertising Costs	Advertising Costs
	We recognize advertising costs as expense when incurred. The total amount charged to advertising expense for the years ended December 31, 2014, 2013 and 2012, were $2.2 million, $2.0 million and $2.0 million, respectively.
Share-Based Compensation	Share-Based Compensation
	We account for share based compensation using the fair value method to recognize compensation cost. See Note 17 for information about share-based compensation and our equity based award plans.
Noncontrolling Redeemable Interest	Noncontrolling Redeemable Interest
	In 1998, in conjunction with the acquisition of an operating partnership that owned two apartment communities, one of which was sold in October 2005, we issued a total of 522,032 operating partnership units ("OP units"). Holders of OP units were entitled to receive cumulative distributions per OP unit equal to the per share distributions on our common shares. When the OP units were presented for redemption, we were obligated to redeem those OP units for either common shares exchangeable on a one-for-one basis, or the cash equivalent amount, determined as the average closing price for our common shares over the 20-day period preceding the redemption, at our option. During 2013, all remaining OP units were canceled by means of a merger, and thus there are no OP units remaining as of December 31, 2013.
Noncontrolling Interest	Noncontrolling Interest
	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 variable interest entity 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 meets the criteria to be classified as a component of permanent equity.
	Index
	On September 24, 2010, we entered into a partnership agreement with Bristol Development Group, an unrelated third-party, for the development of Vista Germantown, a 242-unit apartment community located in downtown Nashville, Tennessee. We contributed $9.4 million to the partnership and held a 90.0% equity interest in the partnership. In February 2013, we funded the redemption of the interest of the minority 10.0% partner of this partnership for $4.5 million, and therefore owned a 100% interest in Vista Germantown as of February 2013. On April 2, 2014, we disposed of Vista Germantown for a sales price of $53.3 million.
Investment in Unconsolidated Entities	Investment in Unconsolidated Entities
	During the quarter ended March 31, 2014, we entered into a partnership agreement with AIG, an unrelated third-party, for the development and operation of 350 8th, a 410-unit apartment community with 40,000 square feet 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. As of December 31, 2013, this land was included in our consolidated financial statements. Upon the formation of our partnership with AIG, the land and improvements to date, with a carrying value of $50.3 million, were deconsolidated. We are a 50.01% partner in this partnership.
	During the quarter ended September 30, 2013, we entered into a partnership agreement with LPC MM Monrovia, LLC ("Lincoln"), an unrelated third-party, for the limited purpose of acquiring a property in Monrovia, California, and to produce construction drawings for improvements to the property, known as 5th and Huntington. The land, upon which the partnership plans to develop a 154-unit multifamily apartment community, was purchased by the partnership on August 9, 2013 for $13.1 million. We are a 50.0% partner with Lincoln. On February 3, 2015 we purchased Lincoln's 50.0% interest in the partnership for $8.4 million, increasing our ownership percentage in the development to 100%. See Note 19 for further information related to this subsequent event.
	During the quarter ended June 30, 2013, we entered into a partnership agreement with Legendary Investors Group No. 1 LLC ("Legendary"), an unrelated third-party for the development and operation of 950 East Third, a 472-unit apartment community with 19,700 square feet of commercial space located in Los Angeles, California. We are a 50.0% partner with Legendary, who contributed the land at a value of $30.0 million to the joint venture.
	As these partnerships are not sufficiently funded to finance the activities of the entities, and not all of the capital will be funded up front, these partnerships are not deemed to have sufficient equity and have therefore been determined to be variable interest entities. It has also been determined that we do not control the decisions that most significantly affect the economics of the entities, and that we do not hold a controlling financial interest in the entities. As such, our investments in the entities are included in our consolidated financial statements using the equity method. To the extent that our cost basis is different from the basis reflected at the unconsolidated entity level, the basis difference is amortized over the life of the related assets.
Derivative Instruments and Hedging Activities	Derivative Instruments and Hedging Activities
	We utilize interest rate swaps to add stability to interest expense and to manage our exposure to interest rate movements. Interest rate swaps, designated as cash flow hedges, involve the receipt of variable-rate amounts in exchange for fixed-rate payments over the life of the agreements without exchange of the underlying principal amount.
	We do not use derivatives for trading or speculative purposes. Further, we have a policy of only entering into contracts with major financial institutions based upon their credit ratings and other factors. When viewed in conjunction with the underlying and offsetting exposure that the derivatives are designed to hedge, we have not sustained a material loss from these hedges.
	We record all derivatives on the balance sheet at fair value. The accounting for changes in the fair value of derivatives depends on the intended use of the derivative and the resulting designation. Derivatives used to hedge the exposure to changes in the fair value of an asset, liability or firm commitment attributable to a particular risk, such as interest rate risk, are considered fair value hedges. Derivatives used to hedge the exposure to variability in expected future cash flows or other types of forecasted transactions are considered cash flow hedges.
	Index
	For derivatives designated as cash flow hedges, the effective portion of changes in the fair value of the derivative is initially reported in other comprehensive income (outside of earnings) and subsequently reclassified to earnings when the hedged transaction affects earnings, and the ineffective portion of changes in the fair value of the derivative is recognized directly in earnings. Hedge ineffectiveness is measured by comparing the changes in fair value or cash flows of the derivative hedging instrument with the changes in fair value or cash flows of the designated hedged item or transaction. For derivatives not designated as hedges, changes in fair value are recognized in earnings. See Note 11 for additional information related to our derivative and hedging activities.
Treasury Shares	Treasury Shares
	We record the purchase of treasury shares at cost. From time to time, we may reissue these shares. When shares are reissued, we account for the issuance based on the "first in, first out" method. For additional information regarding treasury shares, see Note 14. We commonly use our treasury shares to provide for restricted share award grants and acquire treasury shares upon the forfeiture of restricted shares, upon the termination of employment prior to vesting and upon surrender of restricted shares in satisfaction of income tax liabilities upon vesting events.
New Accounting Standards	New Accounting Standards
	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. See Note 3 for additional information related to how ASU 2014-08 affects our current reporting. 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.
	Revenue
	In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606) ("ASU 2014-09"). ASU 2014-09 is a comprehensive new revenue recognition model requiring a company to depict the transfer of goods or services to a customer at an amount reflecting the consideration it expects to receive in exchange for those goods or services. In adopting ASU 2014-09, companies may use either a full retrospective or a modified retrospective approach. Additionally, this guidance requires improved disclosures regarding the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers. ASU 2014-09 is effective for the first interim period within annual reporting periods beginning after December 15, 2016, and early adoption is not permitted. The Company is currently evaluating the impact the adoption of ASU 2014-09 will have on the Company’s financial position or results of operations.
	Index
	Going Concern
	In August 2014, the FASB issued ASU 2014-15, Presentation of Financial Statements - Going Concern (Subtopic 205-40) ("ASU 2014-15"). ASU 2014-15 was issued to give clarity to stakeholders when there are conditions or events that raise substantial doubt about an entity’s ability to continue as a going concern. The guidance calls for, in connection with the preparation of financial statements for each annual and interim reporting period, an evaluation by management over whether there are conditions or events, considered in the aggregate, that raise substantial doubt about the Company’s ability to continue as a going concern within one year after the date that the financial statements are issued (or are available to be issued). ASU 2014-15 is effective for the annual reporting periods ending after December 15, 2016. ASU 2014-15 will become effective for the Company on January 1, 2016. At this time, the adoption of ASU 2014-15 is not expected to impact the Company's consolidated financial statements or disclosures.
Adjustments to Previously Issued Financial Statements	Adjustments to Previously Issued Financial Statements
	In connection with the preparation of the financial statements as of June 30, 2014, we identified an adjustment related to the reporting of cash expenditures for development fixed asset additions and the related non-cash investing disclosure which impacted the Consolidated Statements of Cash Flows for the Year Ended December 31, 2013, by reducing cash flow from operating activities and cash used for investing activities. To correctly present cash flows expended for development fixed asset additions, the Consolidated Statements of Cash Flows includes an adjustment of $8.3 million to increase net cash flow provided by operating activities, as well as a corresponding increase to net cash flow used for investing activities for the year ended December 31, 2013. We assessed the materiality of the foregoing adjustment on the prior period financial statements by examining and assessing the pertinent quantitative and qualitative criteria, and concluded that it was not material to the prior period. However, we determined it was appropriate to revise the applicable financial statements in this filing with the SEC. The following are selected line items from our Consolidated Statements of Cash Flows for the Year Ended December 31, 2013 illustrating the affect of the adjustment thereon:
			As Previously
	(in thousands)		Reported			Adjustment			As Revised
	Cash flow from operating activities:
	Net change in assets and liabilities:
	Accounts payable and accrued expenses		$	(3,267	)	$	8,262		$	4,995
	Total adjustments		$	12,268		$	8,262		$	20,530
	Net cash flow provided by operating activities		$	73,563		$	8,262		$	81,825
	Cash flow from investing activities:
	Development fixed asset additions		$	(77,094	)	$	(8,262	)	$	(85,356	)
	Net cash flow used for investing activities		$	(211,176	)	$	(8,262	)	$	(219,438	)
	Supplemental disclosure of non-cash information:
	Net change in accounts payable related to fixed asset additions		$	14,360		$	(8,262	)	$	6,098
	There is no impact on these adjustments to the Consolidated Balance Sheets, Consolidated Statement of Shareholders’ Equity or Consolidated Statements of Operations and Comprehensive Income of the Company in any previously reported periods or any interim periods reported during the year ended December 31, 2013.

Significant_Accounting_Policie2

Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Property, Plant and Equipment [Table Text Block]	Depreciation is provided on a straight-line basis over the estimated useful lives of the assets as follows:
	Buildings and improvements	5 - 30 years
	Furniture, fixtures and equipment	5 - 10 years
Schedule of Error Corrections and Prior Period Adjustments [Table Text Block]	The following are selected line items from our Consolidated Statements of Cash Flows for the Year Ended December 31, 2013 illustrating the affect of the adjustment thereon:
			As Previously
	(in thousands)		Reported			Adjustment			As Revised
	Cash flow from operating activities:
	Net change in assets and liabilities:
	Accounts payable and accrued expenses		$	(3,267	)	$	8,262		$	4,995
	Total adjustments		$	12,268		$	8,262		$	20,530
	Net cash flow provided by operating activities		$	73,563		$	8,262		$	81,825
	Cash flow from investing activities:
	Development fixed asset additions		$	(77,094	)	$	(8,262	)	$	(85,356	)
	Net cash flow used for investing activities		$	(211,176	)	$	(8,262	)	$	(219,438	)
	Supplemental disclosure of non-cash information:
	Net change in accounts payable related to fixed asset additions		$	14,360		$	(8,262	)	$	6,098

Acquisition_Development_Constr1

Acquisition, Development, Construction and Disposition Activity (Tables)	12 Months Ended
	Dec. 31, 2014
Acquisition, Development, Construction and Disposition Activity [Abstract]
Schedule of acquired properties	The following table provides information on the operating property acquired during 2014 (purchase price in thousands):
	Acquisition Date		Property		Location		Units			Purchase Price
	10-Jun-14		Alpha Mill Phase I and Phase II		Charlotte, NC		267			$	45,075
	The following table provides information on operating properties acquired during 2013 (purchase price in thousands):
	Acquisition Date		Property		Location		Units			Purchase Price
	19-Nov-13		Lofts at Weston Lakeside		Cary, NC		215			$	38,300
	18-Nov-13		St. Mary's Square		Raleigh, NC		134			27,325
	10-Oct-13		The Apartments at Blakeney (1)		Charlotte, NC		295			53,180
	27-Sep-13		Rienzi at Turtle Creek		Dallas, TX		152			48,900
	16-Jul-13		Doral West		Doral, FL		388			93,500
							1,184			$	261,205
	-1	Purchase price includes assumed $28.0 million loan. Principal balance of loan assumed approximated fair value at time of acquisition.
	The following table provides information on operating properties acquired during 2012 (purchase price in thousands):
	Acquisition Date		Property		Location		Units			Purchase Price
	28-Aug-12		The Park at Crossroads (1)		Cary, NC		344			$	35,200
	23-Jul-12		21 Forty Medical District		Dallas, TX		396			53,350
	17-Jul-12		Southpoint Village		Durham, NC		211			34,800
	23-May-12		The Apartments at the Arboretum		Cary, NC		205			39,250
	8-May-12		Desmond's Tower (2)		Los Angeles, CA		—			20,000
							1,156			$	182,600
	-1	Purchase price includes assumed $24.9 million loan, with a fair value of $27.6 million.
	-2	In conjunction with our May 2012 acquisition of land for development of an apartment community, we acquired an operating commercial building. This amount represents the purchase price allocation of the commercial building component only. The purchase price allocation of $17.3 million, representing the parking lot to be used for development, is included in the "Consolidated Current Development" table within this Note.
Pro Forma Financial Information	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 acquisitions occurred at such time.
	Index
		Year Ended December 31,
	(Pro forma amounts unaudited; in thousands, except per share data)	2014				2013				2012
	Actual revenue from acquisitions	$	1,934			$	6,448			$	7,978
	Actual net income (loss) from acquisitions	17				(240		)		51
	Pro forma revenue	195,140				196,212				184,294
	Pro forma net income applicable to common shares	144,943				63,929				32,210
	Pro forma earnings per common share - basic:
	Pro forma net income applicable to common shares	$	2.52			$	1.24			$	0.7
	Pro forma earnings per common share - diluted:
	Pro forma net income applicable to common shares	$	2.5			$	1.23			$	0.7
Purchase Price Allocation	The table below provides details for the two remaining properties we plan to acquire:
	(Dollar amounts in thousands)
	Property		Location		Units			Estimated Closing Period		Purchase Price
	1160 Hammond		Atlanta, GA		345			Q1 2015		$	80,350
	Varela Westshore		Tampa, FL		350			Q2 2015		79,450
					695					$	159,800
	The purchase price allocations for the operating properties acquired were as follows:
		December 31,
	(In thousands)	2014				2013				2012
	Land	$	8,140			$	28,578			$	25,638
	Buildings and improvements	36,044				225,792				150,028
	Furniture and fixtures	468				3,313				3,197
	Existing leases (Other assets) (1)	423				3,522				6,313
	Assumed debt (2) (3)	—				(28,000		)		(27,589		)
	Other liabilities	—				—				101
	Total	$	45,075			$	233,205			$	157,688
	-1	See Note 5 for additional information related to intangible assets identified as existing leases.
	-2	Fair value was equal to principal amount of loan assumed in 2013 at the time of acquisition.
	-3	Fair value amount of loan assumed in 2012 at the time of acquisition; actual principal amount of loan assumed was $24.9 million,
Schedule of Completed, Current And Future Development	The following table identifies our consolidated development activity on which construction has commenced:
	(Dollar amounts in thousands)
											Total
											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	%		249			$	56,800		$	52,373		$	32,006		Q2 2013		Q1 2015
	7001 Arlington at Bethesda		Bethesda, MD		98.1	%	(2)	140			$	53,400		$	46,658		$	16,673		Q4 2012		Q2 2015
	The Desmond on Wilshire		Los Angeles, CA		100	%		175			$	76,300		$	44,982		$	—		Q2 2013		Q4 2015
	Total							564			$	186,500		$	144,013		$	48,679
	-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 projections as of February 3, 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.
	Index
	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	%		410			$	245,000		$	82,647		$	39,172		$	—		$	—	(2)	Q2 2014	Q4 2016
	950 East Third		Los Angeles, CA		50	%		472			$	164,000		$	38,505		$	7,730		$	—		$	—		Q3 2014	Q1 2017
	Total							882			$	409,000		$	121,152		$	46,902		$	—		$	—
	-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 projections as of February 3, 2015.
	-2	AEC has guaranteed 100% of a $143.6 million construction loan which had no outstanding balance as of December 31, 2014.
	The following table identifies our development activity that is in the planning phase:
	(Dollar amounts in thousands)												AEC						AEC
							Estimated			Cost to			Investment			Total			Share of
	Name		Location		Ownership %		Total Units (1)			Date			to Date			Debt			Debt
	5th and Huntington (2)		Monrovia, CA		50.00%		154			$	15,331		$	7,898		$	—		$	—
	Warner Center		Woodland Hills, CA		100.00%		379			$	17,519		$	17,519		$	—		$	—
	-1	Based on current projections as of February 3, 2015.
	-2	5th and Huntington is an unconsolidated development project as of December 31, 2014. On February 3, 2015, we purchased our partner's 50.0% interest in the partnership for $8.4 million, increasing our ownership percentage in the development to 100%. See Note 19 for further information related to this subsequent event.
Summary of Income from Discontinued Operations	The following table summarizes "Income from discontinued operations:"
	(In thousands)		2013				2012
	Revenue
	Property revenue		$	9,191			$	21,649
	Expenses
	Property operating and maintenance		4,233				10,351
	Depreciation and amortization		1,779				5,606
	Total expenses		6,012				15,957
	Operating income		3,179				5,692
	Interest expense		—				(1,811		)
	Operating income, net of interest expense		3,179				3,881
	Gain on disposition of properties		52,828				26,849
	Income from discontinued operations		$	56,007			$	30,730

Restricted_Cash_Tables

Restricted Cash (Tables)	12 Months Ended
	Dec. 31, 2014
Restricted Cash [Abstract]
Schedule of Restricted Cash and Cash Equivalents [Table Text Block]	Restricted cash is comprised of the following:
		December 31,
	(In thousands)	2014		2013
	Resident security deposits	$	1,128	$	1,524
	Other escrows	43,295		20
	Deferred compensation	746		560
	Escrows and reserve funds for replacements
	required by mortgages	1,192		1,361
		$	46,361	$	3,465

Goodwill_and_Other_Assets_Tabl

Goodwill and Other Assets (Tables)	12 Months Ended
	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Other assets, net	Other assets, net, consist of the following:
		December 31,
	(In thousands)	2014			2013
	Intangible assets	$	5,812		$	9,834
	Less: accumulated amortization	(4,925		)	(6,093		)
		887			3,741
	Prepaid expenses	4,741			4,029
	Deferred financing costs, net	7,177			8,559
	Deposits on potential future acquisitions	14,006			17,943
	Other assets	2,336			3,687
		$	29,147		$	37,959
Existing leases and tenant relationships	Our intangible assets related to existing leases consist of the following:
	(In thousands)	December 31,
		2014			2013
	Gross carrying amount	$	5,812		$	9,834
	Less: accumulated amortization	(4,925		)	(6,093		)
		$	887		$	3,741
Scheduled amortization for each of the next five years	As of December 31, 2014, the scheduled amortization for each of the next five years are as follows (in thousands):
	2015	$	374
	2016	374
	2017	139
	2018	—
	2019	—
		$	887

Debt_Tables

Debt (Tables)	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Outstanding debt instruments	The following table identifies our total debt outstanding and weighted average interest rates:
		31-Dec-14						31-Dec-13
					Weighted					Weighted
		Balance			Average			Balance		Average
	(Dollar amounts in thousands)	Outstanding			Interest Rate			Outstanding		Interest Rate
	Fixed Rate Debt:
	Secured	$	223,934		4.8	%		$	271,374	4.9	%
	Unsecured - notes	250,000			4.4	%		250,000		4.4	%
	Total Fixed Rate Debt	473,934			4.6	%		521,374		4.7	%
	Variable Rate Debt Swapped to Fixed:
	Unsecured - term loan	125,000			2.7	%		125,000		3	%
	Total Variable Rate Debt Swapped to Fixed	125,000			2.7	%		125,000		3	%
	Variable Rate Debt Unhedged:
	Secured	48,679			1.5	%		8,100		1.5	%
	Unsecured - revolving credit facility	76,500			1.5	%		133,500		1.5	%
	Unsecured - term loan	25,000			1.6	%		25,000		1.9	%
	Total Variable Rate Debt Unhedged	150,179			1.5	%		166,600		1.5	%
	Total Debt	$	749,113		3.7	%		$	812,974	3.8	%
Scheduled debt maturities	As of December 31, 2014, the scheduled payments of principal on all debt for each of the next five years and thereafter, are as follows (in thousands):
	2015		$	21,446
	2016		89,502
	2017		77,906
	2018		49,066
	2019		12,005
	Thereafter		497,797
	Net unamortized premium		1,391
			$	749,113
Mortgage notes payable	The following table provides information on loans repaid during 2014:
			Loans Repaid
	(Dollar amounts in thousands)					Interest
	Property		Amount			Rate (2)
	Residence at White River		$	9,221		5.40%
	Spring Valley		10,817			5.40%
	The Alexander at Ghent		24,500			5.60%
	Total / weighted average rate		$	44,538		5.50%	(1)
	-1	Represents weighted average interest rate for the loans listed.
	-2	Represents interest rate at the time of repayment.

Noncontrolling_Interests_Table

Noncontrolling Interests Tables (Tables)	12 Months Ended
	Dec. 31, 2014
Noncontrolling Interest [Line Items]
Redeemable Noncontrolling Interest [Table Text Block]	Activity related to the noncontrolling redeemable interest is as follows:
		For the year ended December 31,
	(In thousands)		2013				2012
	Balance at beginning of period		$	1,734			$	1,734
	Net income attributable to noncontrolling redeemable interest		42				54
	Distribution to noncontrolling redeemable interest		(42		)		(54		)
	Redemption of Operating Partnership units		(1,734		)		—
	Balance at end of period		$	—			$	1,734
Noncontrolling Interest Activity [Table Text Block]	The following table provides details of the activity related to noncontrolling interests:
		December 31,
	(In thousands)	2014				2013
	Balance at beginning of period	$	350			$	1,344
	Net income	—				3
	Purchase of noncontrolling interest	—				(997		)
	Balance at end of period	$	350			$	350
	The following table provides details of the activity related to changes in ownership of noncontrolling interests:
		December 31,
	(In thousands)	2014				2013
	Net income attributable to AERC	$	144,711			$	61,250
	Decrease in equity for purchase of noncontrolling interest	—				(3,547		)
	Change from net income attributable to AERC and net
	transfers to noncontrolling interest	$	144,711			$	57,703

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Reconciliation Between GAAP Net Income And Taxable Income [Table Text Block]	Reconciliation between GAAP net income and taxable income:
					Year Ended December 31,
	(In thousands)				2014				2013				2012
	GAAP net income				$	144,711			$	61,250			$	30,592
	Add:		GAAP net income of taxable REIT subsidiaries
			and noncontrolling redeemable interest, net		92				15				1,224
	GAAP net income from REIT operations (1)				144,803				61,265				31,816
	Add:		Book depreciation and amortization		65,437				61,834				57,672
	Less:		Tax depreciation and amortization		(42,467		)		(41,661		)		(39,835		)
			Book/tax differences on gains from
			capital transactions		(112,844		)		(50,472		)		(19,128		)
	Other book/tax differences, net				(2,602		)		(4,616		)		1,088
	Taxable income before adjustments				52,327				26,350				31,613
	Less:		Capital gain		(20,410		)		(2,356		)		(7,762		)
	Taxable income subject to dividend requirements				$	31,917			$	23,994			$	23,851
	-1	All adjustments to GAAP net income from REIT operations are net of amounts attributable to taxable REIT subsidiaries and noncontrolling interests.
Reconciliation Between Cash Dividends Paid And Dividends Paid Decuction [Table Text Block]	Reconciliation between cash dividends paid and dividends paid deduction:
			Year Ended December 31,
	(In thousands)		2014				2013				2012
	Cash dividends paid		$	43,919			$	38,933			$	32,406
	Add: Dividends designated from following year		10,473				—				—
	Less: Portion designated as capital gain distribution		(20,403		)		(2,356		)		(7,762		)
	Less: Return of capital		—				(12,583		)		(793		)
	Dividends paid deduction		$	33,989			$	23,994			$	23,851
Dividends Per Common Share	Total dividends per common share and the related components for the years ended December 31, 2014, 2013 and 2012, as reported for income tax purposes, were as follows:
	Year Ended December 31, 2014
							Non-Taxable				Total				Unrecaptured
			Ordinary				Return of				Capital				Section 1250
	Date Paid		Income				Capital				Gain				Gain		Dividends
	2/3/14		$	0.118729			$	—			$	0.071271			$	0.017614	$	0.19
	5/1/14		0.118729				—				0.071271				0.017614		0.19
	8/1/14		0.118729				—				0.071271				0.017614		0.19
	11/3/14		0.124978				—				0.075022				0.018541		0.2
	1/30/15	(1)	0.11461				—				0.068799				0.017003		0.183409
			$	0.595775			$	—			$	0.357634			$	0.088386	$	0.953409
	-1	Represents a portion of the dividend paid on January 30, 2015. The remaining portion of this dividend will be reported for the year ended December 31, 2015 for income tax purposes.
	Index
	Year Ended December 31, 2013
							Non-Taxable				Total				Unrecaptured
			Ordinary				Return of				Capital				Section 1250
	Date Paid		Income				Capital				Gain				Gain		Dividends
	2/1/13		$	0.129355			$	0.049149			$	0.011496			$	0.011496	$	0.19
	5/1/13		0.129355				0.049149				0.011496				0.011496		0.19
	8/1/13		0.129355				0.049149				0.011496				0.011496		0.19
	11/1/13		0.129355				0.049149				0.011496				0.011496		0.19
			$	0.51742			$	0.196596			$	0.045984			$	0.045984	$	0.76
	Year Ended December 31, 2012
							Non-Taxable				Total				Unrecaptured
			Ordinary				Return of				Capital				Section 1250
	Date Paid		Income				Capital				Gain				Gain		Dividends
	2/1/12		$	0.140533			$	0.009077			$	0.02039			$	0.017826	$	0.17
	5/1/12		0.1488				0.009611				0.021589				0.018875		0.18
	8/1/12		0.1488				0.009611				0.021589				0.018875		0.18
	11/1/12		0.1488				0.009611				0.021589				0.018875		0.18
			$	0.586933			$	0.03791			$	0.085157			$	0.074451	$	0.71

Derivative_and_Hedging_Activit1

Derivative and Hedging Activities (Tables)	12 Months Ended
	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block]	As of December 31, 2014, 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		2		$125.0 million
Fair value of derivative instruments	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 December 31, 2014						As of December 31, 2013
	(In thousands)	Balance Sheet Location		Fair Value				Balance Sheet Location		Fair Value
	Derivatives designated
	as hedging instruments:
	Interest rate swap	Other assets, net		$	256			Other assets, net		$	1,573
	Fair Value of Derivative Instruments
		Liability Derivatives
		As of December 31, 2014						As of December 31, 2013
	(in thousands)	Balance Sheet Location		Fair Value				Balance Sheet Location		Fair Value
	Derivatives designated
	as hedging instruments:
	Interest rate swap	Accounts payable and						Accounts payable and
		other liabilities		$	1,349			other liabilities		$	2,275
Effect of derivative instruments on the consolidated statements of operations	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
	(In thousands)		Location of Gain or		Year Ended
	Derivatives in Cash Flow Hedging		(Loss) Recognized		December 31,				December 31,				December 31,
	Relationships (Interest Rate Swaps)		in Income on Derivative		2014				2013				2012
	Amount of gain/(loss) recognized in OCI on derivative				$	(1,790	)		$	1,454			$	(2,529	)
	Amount of loss reclassified from accumulated
	OCI into interest expense		Interest expense		$	(1,399	)		$	(778	)		$	—
	Amount of gain/(loss) recognized in income
	on derivative (ineffective portion and amount
	excluded from effectiveness testing)		Other expense		$	—			$	—			$	—
Offsetting Assets [Table Text Block]
	Offsetting of Derivative Assets and Liabilities
															Gross Amounts Not Offset
											Net Amounts of				in 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-Dec-14
	Offsetting Derivative
	Assets		$	256			$	—			$	256			$	—	$	—	$	256
	Liabilities		$	1,349			$	—			$	1,349			$	—	$	—	$	1,349
	31-Dec-13
	Offsetting Derivative
	Assets		$	1,573			$	—			$	1,573			$	—	$	—	$	1,573
	Liabilities		$	2,275			$	—			$	2,275			$	—	$	—	$	2,275

Fair_Value_Tables

Fair Value (Tables)	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Schedule of liabilities measured at fair value
				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		—
				Fair Value at December 31, 2013 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	$	279,474	$	—	$	—	$	284,886
	Unsecured debt	533,500		—		530,022		—

Supplemental_Disclosure_of_Cas1

Supplemental Disclosure of Cash Flow Information (Tables)	12 Months Ended
	Dec. 31, 2014
Supplemental Cash Flow Information [Abstract]
Schedule of Cash Flow, Supplemental Disclosures [Table Text Block]	The following table summarizes our non-cash investing and financing activities which are not reflected in the Consolidated Statements of Cash Flows:
		Year Ended December 31,
	(In thousands)	2014			2013			2012
	Dividends declared but not paid	$	12,886		$	12,178		$	10,149
	Issuance of shares for share-based compensation	1,969			—			1,916
	Net change in accounts payable related to fixed asset additions (1)	7,890			6,098			1,362
	Net change in accounts payable and security deposits
	related to disposition of operating properties	(698		)	(890		)	(638		)
	Net change in accounts payable and security deposits
	related to acquisition of operating properties	117			1,800			1,072
	Deconsolidation of net assets	26,238			—			—
	Mortgage loan assumed (2) (3)	—			28,000			27,589
	-1	Refer to Note 2 for information on adjustments made to previously issued financial statements.
	-2	The principal balance on loan assumed in 2013 approximated fair value at time of acquisition.
	-3	The fair value amount of loan assumed in 2012 at time of acquisition; the principal balance at time of acquisition was $24.9 million. Fair value was determined based on an interest rate of 3.1%.

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Earnings Per Share
			Year Ended December 31,
	(In thousands, except per share amounts)		2014			2013			2012
	Numerator - basic and diluted:
	Income (loss) from continuing operations		$	144,711		$	5,288		$	(119	)
	Net income attributable to noncontrolling interests		—			(45		)	(19		)
	Allocation to participating securities		(473		)	(19		)	—
	Income (loss) from continuing operations applicable to common shares		$	144,238		$	5,224		$	(138	)
	Income from discontinued operations		$	—		$	56,007		$	30,730
	Allocation to participating securities		—			(209		)	—
	Income from discontinued operations applicable to common shares		$	—		$	55,798		$	30,730
	Denominator - basic:		57,478			51,622			46,063
	Effect of dilutive securities (1)		497			562			—
	Denominator - diluted:		57,975			52,184			46,063
	Net income applicable to common shares - basic:
	Income from continuing operations applicable to common shares		$	2.51		$	0.1		$	—
	Income from discontinued operations		—			1.08			0.66
	Net income applicable to common shares - basic		$	2.51		$	1.18		$	0.66
	Net income applicable to common shares - diluted:
	Income from continuing operations applicable to common shares		$	2.49		$	0.1		$	—
	Income from discontinued operations		—			1.07			0.66
	Net income applicable to common shares - diluted		$	2.49		$	1.17		$	0.66
	-1	For the twelve months ended December 31, 2013, the Company has excluded 10 stock options as their inclusion would be anti-dilutive. For the twelve months ended December 31, 2012, all potential common shares are excluded as they are anti-dilutive to the net loss from continuing operations.

Employee_Benefit_Plans_Tables

Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
Schedule of Defined Contribution Plans [Table Text Block]	The following table summarizes the changes in SERP balances for the years ended December 31:
	(In thousands)	2014		2013		2012
	Balance at beginning of period	$	2,520	$	2,283	$	2,067
	Service cost	80		81		77
	Interest cost	174		156		139
	Balance at end of period	$	2,774	$	2,520	$	2,283

Equity_Based_Award_Plans_Table

Equity Based Award Plans (Tables)	12 Months Ended
	Dec. 31, 2014
Share-based Compensation [Abstract]
Options outstanding and exerciseable by plan	Options outstanding and exercisable at December 31, 2014, were as follows:
		Options			Options
		Outstanding			Exercisable
	2011 Plan	61,286			19,620
	2001 Plan	299,090			299,090
		360,376			318,710
Restricted share activity	The following table represents restricted share and DRSU activity for the year ended December 31, 2014:
					Weighted			Weighted
		Number of			Average			Average
		Restricted			Grant-Date		Number of	Grant-Date
		Shares			Fair Value		DRSUs	Fair Value
	Nonvested at beginning of period	735,184			$	10.52	34,797	$	17.15
	Granted	161,267			$	16.11	45,365	$	17.06
	Vested	175,287			$	16.39	26,603	$	17.38
	Forfeited	18,304			$	11.39	8,194	$	16.38
	Nonvested at end of period	702,860			$	10.31	45,365	$	17.06
Assumption ranges 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 assumptions	The weighted average Black-Scholes assumptions and fair value for 2012 were as follows:
	Expected volatility	33.9		%
	Risk-free interest rate	1.3		%
	Expected life of options	7 years
	Dividend yield	4.7		%
	Grant-date fair value	$	2.97
Stock option activity	The following table represents stock option activity for the year ended December 31, 2014:
							Weighted-
		Number of			Weighted-		Average
		Stock			Average		Remaining
		Options			Exercise Price		Contract Life
	Outstanding at beginning of period	510,020			$	11.47
	Exercised	80,930			$	9.07
	Forfeited	68,714			$	15.2
	Outstanding at end of period	360,376			$	11.29	2.1
	Exercisable at end of period	318,710			$	10.77	1.4

Quarterly_Financial_Informatio1

Quarterly Financial Information (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
QUARTERLY FINANCIAL INFORMATION (UNAUDITED)
		2014
		First		Second		Third		Fourth
	(In thousands, except per share data)	Quarter		Quarter		Quarter		Quarter
	Revenue	$	49,715	$	47,902	$	48,207	$	48,256
	Operating income	$	8,260	$	9,031	$	9,805	$	10,336
	Net income	$	42,273	$	62,348	$	3,418	$	36,672
	Net income attributable to AERC	$	42,273	$	62,348	$	3,418	$	36,672
	Basic earnings per common share	$	0.73	$	1.08	$	0.06	$	0.64
	Diluted earnings per common share	$	0.73	$	1.07	$	0.06	$	0.63
		2013
		First		Second		Third		Fourth
	(In thousands, except per share data)	Quarter		Quarter		Quarter		Quarter
	Revenue	$	42,856	$	43,484	$	46,069	$	49,070
	Operating income	$	7,550	$	8,322	$	8,963	$	9,795
	Net income	$	10,363	$	1,652	$	20,007	$	29,273
	Net income attributable to AERC	$	10,346	$	1,638	$	19,993	$	29,273
	Basic earnings per common share	$	0.21	$	0.03	$	0.4	$	0.51
	Diluted earnings per common share	$	0.2	$	0.03	$	0.4	$	0.51

Business_Details

Business (Details)	Dec. 31, 2014
	States
	Units
	Communities
Real Estate Properties [Line Items]
Number of real estate properties	49
Apartment units owned	12,734
Number of states	8
Desmond's Tower [Member]
Real Estate Properties [Line Items]
Square feet of space	78,800

Significant_Accounting_Policie3

Significant Accounting Policies (Details) (USD $)	12 Months Ended					1 Months Ended
	Dec. 31, 2014		Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 1998	Oct. 31, 2005	Sep. 24, 2010	Mar. 31, 2012	Dec. 31, 2011
	Subsidiaries		Properties	Properties		Properties
	Segment
	Properties
	Units
Capitalized Costs of Unproved Properties Excluded from Amortization [Line Items]
Equity interest	50.00%
Number of reportable segments	1
Interest costs capitalized	$4,800,000		$3,600,000	$1,500,000
Payroll costs capitalized	3,500,000		2,800,000	2,400,000
Number of properties recorded as impaired	0		0	0
Number of properties classified as held for sale	0		0
Distribution as percentage of taxable income, tax deductible threshold	90.00%
Number of Taxable REIT Subsidiaries	2
Rents	1,093,000		1,230,000
Advertising expense	2,200,000		2,000,000	2,000,000
Opertating partnership units issued					522,032
Period preceding redemption			20
Units remaining	0		0
Units to acquire	12,734
Purchase of noncontrolling interest			4,500,000
Proceeds from sale of property	216,400,000		139,000,000	67,300,000
Units redeemed			74,083	0
Quantifying Misstatement in Current Year Financial Statements, Amount	8,300,000
Minimum [Member]
Capitalized Costs of Unproved Properties Excluded from Amortization [Line Items]
Useful life of intangible assets	6 months
Maximum [Member]
Capitalized Costs of Unproved Properties Excluded from Amortization [Line Items]
Useful life of intangible assets	12 months
Building and improvements [Member] | Minimum [Member]
Capitalized Costs of Unproved Properties Excluded from Amortization [Line Items]
Useful lives of assets	5 years
Building and improvements [Member] | Maximum [Member]
Capitalized Costs of Unproved Properties Excluded from Amortization [Line Items]
Useful lives of assets	30 years
Furniture, fixtures and equipment [Member] | Minimum [Member]
Capitalized Costs of Unproved Properties Excluded from Amortization [Line Items]
Useful lives of assets	5 years
Furniture, fixtures and equipment [Member] | Maximum [Member]
Capitalized Costs of Unproved Properties Excluded from Amortization [Line Items]
Useful lives of assets	10 years
Common Stock
Capitalized Costs of Unproved Properties Excluded from Amortization [Line Items]
Equity interest	100.00%
Down REIT Operating Patnership Florida [Member]
Capitalized Costs of Unproved Properties Excluded from Amortization [Line Items]
Number of real estate assets contributed	2
Number of properties sold						1
Germantown [Member]
Capitalized Costs of Unproved Properties Excluded from Amortization [Line Items]
Equity interest in partnership	100.00%		100.00%	90.00%			90.00%
Units to acquire	242		242
Contributions in aid of construction	9,400,000						9,400,000
Redeemed ownership percentage			10.00%
Proceeds from sale of property	53,300,000
7001 Arlington at Bethesda [Member]
Capitalized Costs of Unproved Properties Excluded from Amortization [Line Items]
Equity interest in partnership	98.10%		97.00%
Area of land	2.5
Cost of land								12,200,000
Units to acquire	140
Area of real estate property to be developed	6,898
950 East Third [Member]
Capitalized Costs of Unproved Properties Excluded from Amortization [Line Items]
Area of real estate property to be developed	19,700
Commercial Lease [Member]
Capitalized Costs of Unproved Properties Excluded from Amortization [Line Items]
Useful life of intangible assets	60 months
Current Development [Member]
Capitalized Costs of Unproved Properties Excluded from Amortization [Line Items]
Units to acquire	882
Current Development [Member] | 7001 Arlington at Bethesda [Member]
Capitalized Costs of Unproved Properties Excluded from Amortization [Line Items]
Equity interest in partnership	98.10%	[1]
Units to acquire	140
Current Development [Member] | 350 8th [Member]
Capitalized Costs of Unproved Properties Excluded from Amortization [Line Items]
Equity interest	50.01%
Units to acquire	410
Purchase price	46,600,000
Equity Method Investment, Book Value of Land Contributed	50,300,000
Current Development [Member] | 950 East Third [Member]
Capitalized Costs of Unproved Properties Excluded from Amortization [Line Items]
Equity interest	50.00%
Units to acquire	472
Equity Method Investment, Contribution of Partner Land Value	30,000,000
Future Development [Member] | 5th and Huntington [Member]
Capitalized Costs of Unproved Properties Excluded from Amortization [Line Items]
Equity interest in partnership	100.00%
Equity interest	50.00%	[2]
Units to acquire	154	[3]
Payment for partners interest	8,400,000
Partnership land	13,100,000
Future Development [Member] | 5th and Huntington [Member]
Capitalized Costs of Unproved Properties Excluded from Amortization [Line Items]
Equity interest	50.00%
Units to acquire	154
Allowance for doubtful accounts
Capitalized Costs of Unproved Properties Excluded from Amortization [Line Items]
Reserves	$69,000		$78,000	$104,000					$141,000
[1]	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.
[2]	5th and Huntington is an unconsolidated development project as of December 31, 2014. On February 3, 2015, we purchased our partner's 50.0% interest in the partnership for $8.4 million, increasing our ownership percentage in the development to 100%. See Note 19 for further information related to this subsequent event.
[3]	Based on current projections as of February 3, 2015.

Significant_Accounting_Policie4

Significant Accounting Policies Out of Period Adjustment (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accounts payable and accrued expenses		$4,995
Total adjustments	-68,479	20,530	39,995
Net cash flow provided by operating activities	76,232	81,825	70,606
Development fixed asset additions		-85,356
Net cash flow provided by (used for) investing activities	32,815	-219,438	-157,319
Net change in accounts payable related to fixes asset additions		6,098
As Reported
Accounts payable and accrued expenses		-3,267
Total adjustments		12,268
Net cash flow provided by operating activities		73,563
Development fixed asset additions		-77,094
Net cash flow provided by (used for) investing activities		-211,176
Net change in accounts payable related to fixes asset additions		14,360
Adjustment
Accounts payable and accrued expenses		8,262
Total adjustments		8,262
Net cash flow provided by operating activities		8,262
Development fixed asset additions		-8,262
Net cash flow provided by (used for) investing activities		-8,262
Net change in accounts payable related to fixes asset additions		($8,262)

Acquisition_Development_Constr2

Acquisition, Development, Construction and Disposition Activity (Details) (USD $)	12 Months Ended						3 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2013		Oct. 10, 2013		Sep. 30, 2013
	Properties		Properties		Properties				Units		Properties
	Units
Business Acquisition [Line Items]
Apartment units owned	12,734
Costs associated with acquisitions	$185,000		$78,000				$78,000
Assumed debt	0		28,000,000	[1]	27,589,000	[1]	28,000,000	[1]
Deposits on potential future acquisitions	14,006,000		17,943,000				17,943,000
Lease up period	18 months
Equity interest	50.00%
Property Dispositions	5		4		6
Disposal Group Operating Income excluding discontinued operations	-3,400,000
Proceeds from sale of property	216,400,000		139,000,000		67,300,000
Gain on disposition of property	133,300,000		52,800,000		26,800,000
Related party commissions	400,000,000		1,100,000
950 East Third [Member]
Business Acquisition [Line Items]
Area of real estate property to be developed	19,700
Warner Center [Member]
Business Acquisition [Line Items]
Purchase price	15,800,000
The Apartments at Blakeney [Member]
Business Acquisition [Line Items]
Purchase price							53,180,000	[2]
Apartment units owned									295	[2]
Assumed debt									28,000,000
Edge [Member]
Business Acquisition [Line Items]
Purchase price	80,200,000
Apartment units owned	331
Deposits on potential future acquisitions	4,000,000
Termination Fee	8,000,000
350 8th [Member]
Business Acquisition [Line Items]
Purchase price	46,600,000
Apartment units owned	410
Area of land	3.36
NorthwoodRavinPortfolio [Member]
Business Acquisition [Line Items]
Purchase price	323,900,000
Number of Real Estate Properties to Acquire											7
Deposits on potential future acquisitions	10,000,000
MARYLAND
Business Acquisition [Line Items]
Property Dispositions	3
TENNESSEE
Business Acquisition [Line Items]
Property Dispositions	1
GEORGIA
Business Acquisition [Line Items]
Property Dispositions			1		1
OHIO
Business Acquisition [Line Items]
Property Dispositions			2		1
FLORIDA
Business Acquisition [Line Items]
Property Dispositions	1		1
MICHIGAN
Business Acquisition [Line Items]
Property Dispositions					4
Hancock Real Estate Strategies [Member]
Business Acquisition [Line Items]
Related party transaction amount	53,300,000		130,900,000
Current Development [Member]
Business Acquisition [Line Items]
Apartment units owned	882
Warner Center [Member] | Future Development [Member]
Business Acquisition [Line Items]
Apartment units owned	379	[3]
Equity interest	100.00%
350 8th [Member] | Current Development [Member]
Business Acquisition [Line Items]
Purchase price	$46,600,000
Apartment units owned	410
Equity interest	50.01%
5th and Huntington [Member] | Future Development [Member]
Business Acquisition [Line Items]
Apartment units owned	154	[3]
Equity interest in partnership	100.00%
Equity interest	50.00%	[4]
5th and Huntington [Member] | Future Development [Member]
Business Acquisition [Line Items]
Apartment units owned	154
Equity interest	50.00%
[1]	Fair value was equal to principal amount of loan assumed in 2013 at the time of acquisition.
[2]	Purchase price includes assumed $28.0 million loan. Principal balance of loan assumed approximated fair value at time of acquisition.
[3]	Based on current projections as of February 3, 2015.
[4]	5th and Huntington is an unconsolidated development project as of December 31, 2014. On February 3, 2015, we purchased our partner's 50.0% interest in the partnership for $8.4 million, increasing our ownership percentage in the development to 100%. See Note 19 for further information related to this subsequent event.

Acquisition_Development_Constr3

Acquisition, Development, Construction and Disposition Activity (Property Purchase) (Details) (USD $)

3 Months Ended

12 Months Ended

3 Months Ended

12 Months Ended

Dec. 31, 2013

Jun. 30, 2014

Sep. 30, 2013

Dec. 31, 2014

Sep. 30, 2012

Jun. 30, 2012

Dec. 31, 2013

Dec. 31, 2012

Nov. 19, 2013

Nov. 18, 2013

Jun. 10, 2014

Oct. 10, 2013

Sep. 27, 2013

Jul. 16, 2013

Aug. 28, 2012

Jul. 23, 2012

Jul. 17, 2012

23-May-12

8-May-12

Units

Units

Units

Units

Units

Units

Units

Units

Units

Units

Units

Units

Business Acquisition [Line Items]

Apartment units owned

12,734

Assumed debt

$28,000,000

[1]

$0

$28,000,000

[1]

$27,589,000

[1]

Mortgage loan assumed

28,000,000

[2]

0

28,000,000

[2]

27,589,000

[3]

Parking lot

3,313,000

468,000

3,313,000

3,197,000

Lofts at Weston Lakeside [Member]

Business Acquisition [Line Items]

Apartment units owned

215

Purchase price

38,300,000

St. Mary's Square [Member]

Business Acquisition [Line Items]

Apartment units owned

134

Purchase price

27,325,000

Alpha Mill Phase I and Phase II [Member]

Business Acquisition [Line Items]

Apartment units owned

267

Purchase price

45,075,000

The Apartments at Blakeney [Member]

Business Acquisition [Line Items]

Apartment units owned

295

[4]

Purchase price

53,180,000

[4]

Assumed debt

28,000,000

Rienzi at Turtle Creek [Member]

Business Acquisition [Line Items]

Apartment units owned

152

Purchase price

48,900,000

Doral West [Member]

Business Acquisition [Line Items]

Apartment units owned

388

Purchase price

93,500,000

Acquisitions in Year 2013 [Member]

Business Acquisition [Line Items]

Apartment units owned

1,184

Purchase price

261,205,000

The Park at Crossroads [Member]

Business Acquisition [Line Items]

Apartment units owned

344

[5]

Purchase price

35,200,000

[5]

Assumed debt

24,900,000

24,900,000

Mortgage loan assumed

27,600,000

[1]

21 Forty Medical District [Member]

Business Acquisition [Line Items]

Apartment units owned

396

Purchase price

53,350,000

Southpoint Village [Member]

Business Acquisition [Line Items]

Apartment units owned

211

Purchase price

34,800,000

The Apartments at the Arboretum [Member]

Business Acquisition [Line Items]

Apartment units owned

205

Purchase price

39,250,000

Desmond's Tower [Member]

Business Acquisition [Line Items]

Apartment units owned

0

[6]

Purchase price

20,000,000

[6]

Acquisitions in Year 2012 [Member]

Business Acquisition [Line Items]

Apartment units owned

1,156

Purchase price

182,600,000

Parking Lot [Member] | Desmond's Tower [Member]

Business Acquisition [Line Items]

Parking lot

17,300,000

[1]

Fair value was equal to principal amount of loan assumed in 2013 at the time of acquisition.

[2]

The principal balance on loan assumed in 2013 approximated fair value at time of acquisition.

[3]

The fair value amount of loan assumed in 2012 at time of acquisition; the principal balance at time of acquisition was $24.9 million. Fair value was determined based on an interest rate of 3.1%.

[4]

Purchase price includes assumed $28.0 million loan. Principal balance of loan assumed approximated fair value at time of acquisition.

[5]

Purchase price includes assumed $24.9 million loan, with a fair value of $27.6 million

[6]

In conjunction with our May 2012 acquisition of land for development of an apartment community, we acquired an operating commercial building. This amount represents the purchase price allocation of the commercial building component only. The purchase price allocation of $17.3 million, representing the parking lot to be used for development, is included in the "Consolidated Current Development" table within this Note.

Acquisition_Development_Constr4

Acquisition, Development, Construction and Disposition Activity (Pro Forma) (Details) (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Acquisition, Developement, Construction and Disposition Activity [Abstract]
Actual revenue from acquisitions	$1,934	$6,448	$7,978
Actual net income (loss) from acquisitions	17	-240	51
Pro forma revenue	195,140	196,212	184,294
Pro forma net income applicable to common shares	$144,943	$63,929	$32,210
Pro forma net income appplicable to common shares	$2.52	$1.24	$0.70
Pro forma net income applicable to common shares	$2.50	$1.23	$0.70

Acquisition_Development_Constr5

Acquisition, Development, Construction and Disposition Activity (Purchase Price Allocation) (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012		Aug. 28, 2012
In Thousands, unless otherwise specified
Business Acquisition [Line Items]
Land	$8,140		$28,578		$25,638
Buildings and improvements	36,044		225,792		150,028
Furniture and fixtures	468		3,313		3,197
Existing leases (Other assets)	423	[1]	3,522	[1]	6,313	[1]
Acquired debt	0		28,000	[2]	27,589	[2]
Other liabilities	0		0		101
Total	45,075		233,205		157,688
The Park at Crossroads [Member]
Business Acquisition [Line Items]
Acquired debt					$24,900		$24,900
[1]	See Note 5 for additional information related to intangible assets identified as existing leases.
[2]	Fair value was equal to principal amount of loan assumed in 2013 at the time of acquisition.

Acquisition_Development_Constr6

Acquisition, Development, Construction and Disposition Activity Acquisition, Development, Construction and Disposition Activity (Schedule of Business Acquisitions) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014
	Units
Business Acquisition [Line Items]
Apartment units owned	12,734
1160 Hammond [Member]
Business Acquisition [Line Items]
Apartment units owned	345
Purchase price	$80,350
Varela [Member]
Business Acquisition [Line Items]
Apartment units owned	350
Purchase price	79,450
Pending Acquisition [Member]
Business Acquisition [Line Items]
Apartment units owned	695
Purchase price	$159,800

Acquisition_Development_Constr7

Acquisition, Development, Construction and Disposition Activity (Development) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013	Dec. 31, 2012
	Units
Business Acquisition [Line Items]
Apartment units owned	12,734
Development costs	$779,000		$912,000	$864,000
Construction in progress	73,581,000		42,793,000
Percentage of development costs to date included	100.00%
Investment in joint ventures	20,811,000		9,271,000	0
Equity interest	50.00%
350 8th [Member]
Business Acquisition [Line Items]
Apartment units owned	410
7001 Arlington at Bethesda [Member]
Business Acquisition [Line Items]
Apartment units owned	140
Equity interest in partnership	98.10%		97.00%
Investment in joint ventures	350,000
Current Development [Member]
Business Acquisition [Line Items]
Apartment units owned	882
Development costs	409,000,000	[1]
Construction in progress	121,152,000
AEC investment to date	46,902,000
Borrowings on construction loan	0
Long-term Construction Loan, Current, AEC Portion	0
Current Development [Member] | 7001 Arlington at Bethesda [Member]
Business Acquisition [Line Items]
Apartment units owned	140
Development costs	53,400,000	[1]
Construction in progress	46,658,000
Construction Loan	16,673,000
Equity interest in partnership	98.10%	[2]
Current Development [Member] | Cantabria at Turtle Creek [Member]
Business Acquisition [Line Items]
Apartment units owned	249
Development costs	56,800,000	[1]
Construction in progress	52,373,000
Borrowings on construction loan	32,000,000		5,900,000
Construction Loan	32,006,000
Equity interest in partnership	100.00%
Current Development [Member] | The Desmond on Wilshire [Member]
Business Acquisition [Line Items]
Apartment units owned	175
Development costs	76,300,000	[1]
Construction in progress	44,982,000
Construction Loan	0
Equity interest in partnership	100.00%
Consolidated Entities [Member]
Business Acquisition [Line Items]
Apartment units owned	564
Development costs	186,500,000	[1]
Construction in progress	144,013,000
Construction Loan	48,679,000
350 8th [Member] | Current Development [Member]
Business Acquisition [Line Items]
Apartment units owned	410
Development costs	245,000,000	[1]
Construction in progress	82,647,000
AEC investment to date	39,172,000
Borrowings on construction loan	0
Long-term Construction Loan, Current, AEC Portion	0	[3]
Construction loan	143,600,000
Equity interest	50.01%
5th and Huntington [Member] | Future Development [Member]
Business Acquisition [Line Items]
Apartment units owned	154	[4]
Construction in progress	15,331,000
AEC investment to date	7,898,000
Borrowings on construction loan	0
Long-term Construction Loan, Current, AEC Portion	0
Equity interest in partnership	100.00%
Equity interest	50.00%	[5]
950 East Third [Member] | Current Development [Member]
Business Acquisition [Line Items]
Apartment units owned	472
Development costs	164,000,000	[1]
Construction in progress	38,505,000
AEC investment to date	7,730,000
Borrowings on construction loan	0
Long-term Construction Loan, Current, AEC Portion	0
Equity interest	50.00%
5th and Huntington [Member] | Future Development [Member]
Business Acquisition [Line Items]
Apartment units owned	154
Equity interest	50.00%
Warner Center [Member] | Future Development [Member]
Business Acquisition [Line Items]
Apartment units owned	379	[4]
Construction in progress	17,519,000
AEC investment to date	17,519,000
Borrowings on construction loan	0
Long-term Construction Loan, Current, AEC Portion	$0
Equity interest	100.00%
[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 projections as of February 3, 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.
[3]	AEC has guaranteed 100% of a $143.6 million construction loan which had no outstanding balance as of December 31, 2014.
[4]	Based on current projections as of February 3, 2015.
[5]	5th and Huntington is an unconsolidated development project as of December 31, 2014. On February 3, 2015, we purchased our partner's 50.0% interest in the partnership for $8.4 million, increasing our ownership percentage in the development to 100%. See Note 19 for further information related to this subsequent event.

Acquisition_Development_Constr8

Acquisition, Development, Construction and Disposition Activity (Income from Discontinued Operations) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Acquisition, Development, Construction and Disposition Activity [Abstract]
Property revenue	$9,191	$21,649
Property operating and maintenance	4,233	10,351
Depreciation and amortization	1,779	5,606
Total expenses	6,012	15,957
Operating income	3,179	5,692
Interest expense	0	-1,811
Operating income, net of interest expense	3,179	3,881
Gain on disposition of properties	52,828	26,849
Income from discontinued operations	$56,007	$30,730

Restricted_Cash_Restricted_Cas

Restricted Cash Restricted Cash Components (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Restricted Cash [Abstract]
Resident security deposits	$1,128	$1,524
Other escrows	43,295	20
Deferred compensation	746	560
Escrows and reserve funds for replacements required by mortgages	1,192	1,361
Restricted cash	$46,361	$3,465

Goodwill_and_Other_Assets_Deta

Goodwill and Other Assets (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Finite-Lived Intangible Assets [Line Items]
Written off goodwill related to sale	$186,000
Goodwill	1,300,000	1,500,000
Amortization period	7 months
Amortization of intangible assets	3,300,000	3,900,000	4,900,000
Gross deferred tax assets	6,900,000	6,900,000	6,900,000
Amortization for deferred financing costs	1,900,000	2,000,000	2,100,000
Lease Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization period	12 months
Number of real estate properties acquired	1	5
Intangible assets acquired	$423,000	$3,500,000
Commercial Lease [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life of intangible assets	60 months
Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life of intangible assets	6 months

Goodwill_and_Other_Assets_Othe

Goodwill and Other Assets (Other Assets) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible assets	$5,812	$9,834
Less: accumulated amortization	-4,925	-6,093
Intangible assets, net	887	3,741
Prepaid expenses	4,741	4,029
Deferred financing costs, net	7,177	8,559
Deposits on potential future acquisitions	14,006	17,943
Other assets	2,336	3,687
Other assets, net	$29,147	$37,959

Goodwill_and_Other_Assets_Leas

Goodwill and Other Assets (Leases) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Goodwill and Intangible Assets Disclosure [Abstract]
Gross carrying amount	$5,812	$9,834
Less: accumulated amortization	-4,925	-6,093
Intangible assets, net	$887	$3,741

Goodwill_and_Other_Assets_Futu

Goodwill and Other Assets (Future Amortization) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Goodwill and Intangible Assets Disclosure [Abstract]
2015	$374
2016	374
2017	139
2018	0
2019	0
Intangible assets, net	$887	$3,741

Investment_In_Unconsolidated_E1

Investment In Unconsolidated Entities (Details) (USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013	Dec. 31, 2012
	Units
Schedule of Equity Method Investments [Line Items]
Apartment units owned	12,734
Equity interest	50.00%
Equity Method Investment, Contribution	$26,238,000		$0	$0
Future Development [Member] | 350 8th [Member]
Schedule of Equity Method Investments [Line Items]
Debt term	5 years
Future Development [Member] | 5th and Huntington [Member]
Schedule of Equity Method Investments [Line Items]
Apartment units owned	154	[1]
Equity interest	50.00%	[2]
Equity Method Investment, Partner Contribution	7,500,000
Borrowings on construction loan	0
Maximum exposure to loss	7,900,000
Partnership land	13,100,000
Payment for partners interest	8,400,000
Equity Method Investment, Contribution	7,900,000
Equity Method Investment, Capitalized Interest	500,000
Equity interest in partnership	100.00%
Current Development [Member]
Schedule of Equity Method Investments [Line Items]
Apartment units owned	882
Borrowings on construction loan	0
Current Development [Member] | 350 8th [Member]
Schedule of Equity Method Investments [Line Items]
Apartment units owned	410
Equity interest	50.01%
Equity Method Investment, Partner Contribution	37,600,000
Purchase price	46,600,000
Equity Method Investment, Book Value of Land Contributed	50,300,000
Construction management fee	360,000
Construction loan	143,600,000
Debt term	5 years
Borrowings on construction loan	0
Maximum exposure to loss	39,200,000
Equity Method Investment, Capitalized Interest	1,300,000
Current Development [Member] | 950 East Third [Member]
Schedule of Equity Method Investments [Line Items]
Apartment units owned	472
Equity interest	50.00%
Construction management fee	250,000
Borrowings on construction loan	0
Maximum exposure to loss	7,700,000
Equity Method Investment, Contribution	7,700,000
Equity Method Investment, Capitalized Interest	480,000
Equity Method Investment, Contribution of Partner Land Value	$30,000,000
[1]	Based on current projections as of February 3, 2015.
[2]	5th and Huntington is an unconsolidated development project as of December 31, 2014. On February 3, 2015, we purchased our partner's 50.0% interest in the partnership for $8.4 million, increasing our ownership percentage in the development to 100%. See Note 19 for further information related to this subsequent event.

Debt_Details

Debt (Details) (USD $)	12 Months Ended					0 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012	Jun. 19, 2013	Jan. 12, 2012
Debt Instrument [Line Items]
Cash paid for interest net of capitalized interest	$25,200,000		$24,900,000		$29,400,000
Interest costs capitalized	4,800,000		3,600,000		1,500,000
Equity interest	50.00%
Investment Interest Rate	14000.00%
Weighted average interest rate	3.70%		3.80%
Investment Interest Rate Range Start	9000.00%
Investment Interest Rate Range End	19000.00%
Issuance of Debt, January [Member]
Debt Instrument [Line Items]
Debt procurement cost	1,000,000
Weighted average interest rate	4.27%
Unsecured debt, face amount	150,000,000
Debt, Weighted Average Term	9 years 2 months
Issuance of Debt, Maturity Tranche One, January [Member]
Debt Instrument [Line Items]
Debt term	8 years
Unsecured debt, face amount	63,000,000
Debt Instrument, Interest Rate, Stated Percentage	4.02%
Issuance of Debt, Maturity Tranche Two, January [Member]
Debt Instrument [Line Items]
Debt term	10 years
Unsecured debt, face amount	87,000,000
Debt Instrument, Interest Rate, Stated Percentage	4.45%
Issuance of Debt, October [Member]
Debt Instrument [Line Items]
Debt procurement cost	800,000		950,000
Weighted average interest rate	4.65%
Unsecured debt, face amount	100,000,000
Debt, Weighted Average Term	8 years 9 months
Issuance of Debt, Maturity Tranche One, October [Member]
Debt Instrument [Line Items]
Debt term	7 years
Unsecured debt, face amount	45,000,000
Debt Instrument, Interest Rate, Stated Percentage	4.29%
Issuance of Debt, Maturity Tranche Two, October [Member]
Debt Instrument [Line Items]
Debt term	10 years 2 months
Unsecured debt, face amount	55,000,000
Debt Instrument, Interest Rate, Stated Percentage	4.94%
Variable Rate Debt Hedged [Member]
Debt Instrument [Line Items]
Weighted average interest rate			3.00%
Project Specific Loans [Member] | Mortgages [Member]
Debt Instrument [Line Items]
Number of mortgage notes payable	10		13
Number Of Mortgage Notes Repaid			5
Construction Loan - Maryland [Member] | Mortgages [Member]
Debt Instrument [Line Items]
Number of mortgage notes payable	1
Construction Loan - Texas [Member] | Mortgages [Member]
Debt Instrument [Line Items]
Number of mortgage notes payable	1
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity							350,000,000
Debt procurement cost						1,200,000
Outstanding borrowings, line of credit facility	76,500,000		133,500,000
Weighted average interest rate	1.47%		1.47%
Loans Repaid [Member]
Debt Instrument [Line Items]
Loans Repaid	44,538,000		129,300,000
Interest Rate	5.50%	[1]	6.10%	[1]
Future Development [Member] | 350 8th [Member]
Debt Instrument [Line Items]
Debt term	5 years
Current Development [Member]
Debt Instrument [Line Items]
Borrowings on construction loan	0
Current Development [Member] | 350 8th [Member]
Debt Instrument [Line Items]
Borrowings on construction loan	0
Equity interest	50.01%
Construction loan	$143,600,000
Debt term	5 years
350 8th [Member]
Debt Instrument [Line Items]
Investment Interest Rate	16000.00%
[1]	Represents weighted average interest rate for the loans listed.

Debt_Debt_Outstanding_Details

Debt (Debt Outstanding) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Debt Instrument [Line Items]
Secured Debt	$272,613	$279,474
Unsecured notes	250,000	250,000
Unsecured Debt	150,000	150,000
Long-term Debt	749,113	812,974
Weighted average interest rate	3.70%	3.80%
Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Secured Debt	223,934	271,374
Secured Debt Weighted Average Interest Rate	4.80%	4.90%
Long-term Debt	473,934	521,374
Weighted average interest rate	4.60%	4.70%
Fixed Rate Debt Unsecured Notes [Member] [Domain]
Debt Instrument [Line Items]
Unsecured notes	250,000	250,000
Unsecured Debt Weighted Average Interest Rate	4.40%	4.40%
Fixed Rate Debt Hedged [Member]
Debt Instrument [Line Items]
Unsecured Debt Weighted Average Interest Rate	2.70%
Weighted average interest rate	2.70%
Variable Rate Debt Hedged [Member]
Debt Instrument [Line Items]
Unsecured Debt		125,000
Unsecured Debt Weighted Average Interest Rate		3.00%
Long-term Debt		125,000
Weighted average interest rate		3.00%
Variable Rate Debt Unhedged [Member]
Debt Instrument [Line Items]
Secured Debt	48,679	8,100
Secured Debt Weighted Average Interest Rate	1.50%	1.50%
Long-term Debt	150,179	166,600
Weighted average interest rate	1.50%	1.50%
Variable Rate Debt Unhedged Revolver [Member] [Member]
Debt Instrument [Line Items]
Unsecured Debt	76,500	133,500
Unsecured Debt Weighted Average Interest Rate	1.50%	1.50%
Variable Rate Debt Unhedged Term Loan [Member] [Domain]
Debt Instrument [Line Items]
Unsecured Debt	$25,000	$25,000
Unsecured Debt Weighted Average Interest Rate	1.60%	1.90%

Debt_Debt_Maturities_Details

Debt (Debt Maturities) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Debt Disclosure [Abstract]
2015	$21,446
2016	89,502
2017	77,906
2018	49,066
2019	12,005
Thereafter	497,797
Net unamortized premium	1,391
Total debt	$749,113	$812,974

Debt_Mortgage_Notes_Payable_De

Debt (Mortgage Notes Payable) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Loans Repaid [Member]
Extinguishment of Debt [Line Items]
Loans Repaid	$44,538		$129,300
Interest Rate	5.50%	[1]	6.10%	[1]
Loans Repaid [Member] | Residence at White River [Member]
Extinguishment of Debt [Line Items]
Loans Repaid	9,221
Interest Rate	5.40%	[2]
Loans Repaid [Member] | Spring Valley [Member]
Extinguishment of Debt [Line Items]
Loans Repaid	10,817
Interest Rate	5.40%	[2]
Loans Repaid [Member] | The Alexander at Ghent [Member]
Extinguishment of Debt [Line Items]
Loans Repaid	24,500
Interest Rate	5.60%	[2]
Current Development [Member]
Extinguishment of Debt [Line Items]
Borrowings on construction loan	0
Bethesda [Member] | Current Development [Member]
Extinguishment of Debt [Line Items]
Borrowings on construction loan	$16,700		$2,200
[1]	Represents weighted average interest rate for the loans listed.
[2]	Represents interest rate at the time of repayment.

Noncontrolling_Interests_Detai

Noncontrolling Interests (Details) (USD $)	12 Months Ended				3 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 1998	Mar. 31, 2013	Oct. 30, 2005	Sep. 24, 2010	Mar. 31, 2012
	Units			Communities		Communities
Noncontrolling Interest [Line Items]
Number of apartment communities acquired				2
Number of apartment communities sold						1
Opertating partnership units issued				522,032
Units redeemed		74,083	0
Operating partnership redemption	$0	$1,393,000	$0
Units remaining	0	0
Apartment units owned	12,734
Proceeds from sale of property	216,400,000	139,000,000	67,300,000
Germantown [Member]
Noncontrolling Interest [Line Items]
Equity interest in partnership	100.00%	100.00%	90.00%				90.00%
Apartment units owned	242	242
Contributions in aid of construction	9,400,000						9,400,000
Redeemed ownership percentage		10.00%
Proceeds from sale of property	53,300,000
7001 Arlington at Bethesda [Member]
Noncontrolling Interest [Line Items]
Equity interest in partnership	98.10%	97.00%
Area of land	2.5
Cost of land								12,200,000
Apartment units owned	140
Area of real estate property to be developed	6,898
Germantown [Member]
Noncontrolling Interest [Line Items]
Operating partnership redemption					4,500,000
Proceeds from sale of property	$53,300,000

Noncontrolling_Interest_Noncon

Noncontrolling Interest (Noncontrolling Redeemable Interest) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Redeemable Noncontrolling Interest [Line Items]
Balance at beginning of the period	$1,734	$1,734
Net income attributable to noncontrolling redeemable interest	42	54
Distribution to noncontrolling redeemable interest	-42	-54
Redemption of operating partnership units	-1,734	0
Balance at end of period	$0	$1,734

Noncontrolling_Interest_Noncon1

Noncontrolling Interest (Noncontrolling Interest Activity) (Details) (USD $)	3 Months Ended								12 Months Ended			3 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 31, 2012
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Balance at beginning of period				$350				$1,344	$350	$1,344
Net income								0		3
Net income attributable to AERC	36,672	3,418	62,348	42,273	29,273	19,993	1,638	10,346	144,711	61,250	30,592
Purchase of noncontrolling interest										4,500
Balance at end of period	350				350				350	350	1,344
Change from net income attributable to AERC and net transfers to noncontrolling interests									144,711	57,703
Bristol Development Group [Member]
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Purchase of noncontrolling interest								0				997
Additional Paid-in Capital
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Net income										-3,547
Purchase of noncontrolling interest									$0	($3,547)

Commitments_and_Contingencies_

Commitments and Contingencies Details (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2012	Dec. 31, 2013
Investment [Line Items]
Equity interest	50.00%
Capital Leases	$0		$0
Real estate pledged as collateral	324,100,000		389,100,000
Intangible Assets, Net (Excluding Goodwill)	$887,000
Cure payment	630000
Share-based Compensation Arrangement by Share-Based Payment Award, Options, Forfeited per Settlement, Number of Shares	63,714
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Number of Shares		125,000
Future Development [Member] | 350 8th [Member]
Investment [Line Items]
Debt term	5 years

Income_Taxes_Details

Income Taxes (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
	Subsidiaries
Distribution as percentage of taxable income, tax deductible threshold	90.00%
Number of Taxable REIT Subsidiaries	2
Operating loss carryforwards	$13,400,000	$13,300,000	$13,200,000
Gross deferred tax assets	6,900,000	6,900,000	6,900,000
Gross deferred tax liabilities	254,000	254,000	246,000
Deferred tax valuation allowance	6,700,000	6,600,000	6,600,000
Net tax basis of properties exceeding the amount set forth in the Consolidated Balance Sheets		5,400,000
Net tax basis of properties under the amount set forth in the Consolidated Balance Sheet	$31,200,000

Income_Taxes_Net_Income_Reconc

Income Taxes (Net Income Reconciliation) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Income Tax Disclosure [Abstract]
GAAP net income	$36,672	$3,418	$62,348	$42,273	$29,273	$19,993	$1,638	$10,346	$144,711		$61,250		$30,592
GAAP net income of taxable REIT subsidiaries and noncontrolling redeemable interest, net									92		15		1,224
GAAP net income from REIT operations									144,803	[1]	61,265	[1]	31,816	[1]
Book depreciation and amortization									65,437		61,834		57,672
Tax depreciation and amortization									-42,467		-41,661		-39,835
Book/tax differences on gains from capital transactions									-112,844		-50,472		-19,128
Other book/tax differences, net									-2,602		-4,616		1,088
Taxable income before adjustments									52,327		26,350		31,613
Capital gain									-20,410		-2,356		-7,762
Taxable income subject to dividend requirements									$31,917		$23,994		$23,851
[1]	All adjustments to GAAP net income from REIT operations are net of amounts attributable to taxable REIT subsidiaries and noncontrolling interests.

Income_Taxes_Dividend_Paid_Ded

Income Taxes (Dividend Paid Deduction) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Cash dividends paid	$43,919	$38,933	$32,406
Dividends designated from following year	10,473	0	0
Portion designated as capital gain distribution	-20,403	-2,356	-7,762
Return of capital	0	-12,583	-793
Dividends paid deduction	$33,989	$23,994	$23,851

Income_Taxes_Dividends_Per_Com

Income Taxes (Dividends Per Common Share) (Details) (USD $)	0 Months Ended												12 Months Ended			0 Months Ended
	Nov. 03, 2014	Aug. 01, 2014	1-May-14	Feb. 03, 2014	Nov. 01, 2013	Aug. 01, 2013	1-May-13	Feb. 01, 2013	Nov. 01, 2012	Aug. 01, 2012	1-May-12	Feb. 01, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jan. 30, 2015
Dividends Payable [Line Items]
Ordinary Income	$0.12	$0.12	$0.12	$0.12	$0.13	$0.13	$0.13	$0.13	$0.15	$0.15	$0.15	$0.14	$0.60	$0.52	$0.59
Non-Taxable Return of Capital	$0	$0	$0	$0	$0.05	$0.05	$0.05	$0.05	$0.01	$0.01	$0.01	$0.01	$0	$0.20	$0.04
Total Capital Gain	$0.08	$0.07	$0.07	$0.07	$0.01	$0.01	$0.01	$0.01	$0.02	$0.02	$0.02	$0.02	$0.36	$0.05	$0.09
Unrecaptured Section 1250 Gain	$0.02	$0.02	$0.02	$0.02	$0.01	$0.01	$0.01	$0.01	$0.02	$0.02	$0.02	$0.02	$0.09	$0.05	$0.07
Dividends	$0.20	$0.19	$0.19	$0.19	$0.19	$0.19	$0.19	$0.19	$0.18	$0.18	$0.18	$0.17	$0.79	$0.76	$0.71
Income tax purposes [Member]
Dividends Payable [Line Items]
Dividends													$0.95
Subsequent Event [Member]
Dividends Payable [Line Items]
Ordinary Income																$0.11	[1]
Non-Taxable Return of Capital																$0	[1]
Total Capital Gain																$0.07	[1]
Unrecaptured Section 1250 Gain																$0.02	[1]
Dividends																$0.18	[1]
[1]	Represents a portion of the dividend paid on January 30, 2015. The remaining portion of this dividend will be reported for the year ended December 31, 2015 for income tax purposes.

Derivative_and_Hedging_Activit2

Derivative and Hedging Activities (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Oct. 19, 2012
Derivative [Line Items]
Forward starting interest rate swap date	19-Dec-11
Unsecured Debt	$150,000,000	$150,000,000
Derivative effective date	7-Jun-13
Credit spread	1.40%
All-in rate	2.66%
Derivative lower range of basis spread	0.90%
Derivative higher range of basis spread	1.90%
Derivative net liability position	1,400,000
Interest payable derivative	92,000
Derivative other comprehensive amount to be reclassified into earnings	1,200,000
2013 derivative [Domain]
Derivative [Line Items]
Forward starting interest rate swap date	2-Apr-13
Notional amount	125,000,000
Derivative effective date	2-Jun-16
Fixed derivative rate	1.55%
All-in rate	2.95%
Fixed Rate Debt Hedged [Member]
Derivative [Line Items]
Notional amount	125,000,000
Fixed derivative rate	1.26%
Fixed Rate Debt Hedged [Member] | 2013 derivative [Domain]
Derivative [Line Items]
Unsecured Debt	125,000,000
Medium-term Notes [Member]
Derivative [Line Items]
Debt face amount			$150,000,000

Derivative_and_Hedging_Activit3

Derivative and Hedging Activities Outstanding Interest Rate Derivatives (Details) (USD $)	Dec. 31, 2014
Derivative [Line Items]
Number of instruments	2
Fixed Rate Debt Hedged [Member]
Derivative [Line Items]
Notional amount	125,000,000

Derivative_and_Hedging_Activit4

Derivative and Hedging Activities Fair Value of Derivative Instruments (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Derivatives, Fair Value [Line Items]
Fair value of derivative asset	$256	$1,573
Fair value of derivative liability	$1,349	$2,275

Derivative_and_Hedging_Activit5

Derivative and Hedging Activities (Effect Of Derivative Instruments On the Consolidated Statements Of Operations) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Derivative [Line Items]
Amount of gain/(loss) recognized in OCI on derivative	($1,790,000)	$1,454,000	($2,529,000)
Amount of loss reclassified from accumulated OCI into interest expense	-1,399,000	-778,000	0
Amount of gain/(loss) recognized in income on derivative (ineffective portion and amount excluded from effectiveness testing)	$0	$0	$0

Derivative_and_Hedging_Activit6

Derivative and Hedging Activities Offsetting Financial Assets and Liabilities (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Offsetting Liabilities [Line Items]
Fair value of derivative asset	$256	$1,573
Fair value of derivative liability	1,349	2,275
Derivative asset amount offset against collateral	0	0
Derivative liability amount offset against collateral	0	0
Derivative asset	256	1,573
Derivative liability	1,349	2,275
Derivative assets financial instruments	0	0
Derivative liabilities financial instruments	0	0
Derivative asset amount not offset against collateral	0	0
Derivative iability amount not offset against collateral	0	0
Derivative [Member]
Offsetting Liabilities [Line Items]
Fair value of derivative liability	$1,349	$2,275

Fair_Value_Textual_Details

Fair Value (Textual) (Details)	Dec. 31, 2014
Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Of Mortage Notes Payable, Loan To Value Ratios	41.00%
Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Of Mortage Notes Payable, Loan To Value Ratios	52.00%

Fair_Value_Details

Fair Value (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage notes payable	$272,613	$279,474
Unsecured debt	476,500	533,500
Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage notes payable	0	0
Unsecured debt	0	0
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage notes payable	0	0
Unsecured debt	489,558	530,022
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage notes payable	283,728	284,886
Unsecured debt	$0	$0

Supplemental_Disclosure_of_Cas2

Supplemental Disclosure of Cash Flow Information (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012		Aug. 28, 2012
Business Acquisition [Line Items]
Dividends declared but not paid	$12,886		$12,178		$10,149
Issuance of shares for share-based compensation	1,969		0		1,916
Net change in accounts payable related to fixed asset additions (1)	7,890	[1]	6,098	[1]	1,362	[1]
Net change in accounts payable and security deposits related to disposition of operating properties	-698		-890		-638
Net change in accounts payable and security deposits related to acquisition of operating properties	117		1,800		1,072
Deconsolidation of net assets	26,238		0		0
Mortgage loan assumed	0		28,000	[2]	27,589	[3]
Assumed debt	0		28,000	[4]	27,589	[4]
Interest rate to determine fair value					3.10%
The Park at Crossroads [Member]
Business Acquisition [Line Items]
Mortgage loan assumed							27,600	[4]
Assumed debt					$24,900		$24,900
[1]	Refer to Note 2 for information on adjustments made to previously issued financial statements.
[2]	The principal balance on loan assumed in 2013 approximated fair value at time of acquisition.
[3]	The fair value amount of loan assumed in 2012 at time of acquisition; the principal balance at time of acquisition was $24.9 million. Fair value was determined based on an interest rate of 3.1%.
[4]	Fair value was equal to principal amount of loan assumed in 2013 at the time of acquisition.

Common_Treasury_and_Preferred_1

Common, Treasury and Preferred Shares (Details) (USD $)	12 Months Ended			9 Months Ended	3 Months Ended		1 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Sep. 30, 2007	Dec. 31, 2008	Dec. 31, 2008	Jul. 31, 2005	Jun. 27, 2012
	Loans
Class of Stock [Line Items]
Stock sold		2,921,667
Gross proceeds from sale of stock	$0	$116,751,000	$98,149,000
Common Stock, Shares Issued	57,708,675	57,595,479		57,595,479
Forward Contract Indexed to Issuer's Equity, Additional Common Shares Option	975,000
Forward Contract Indexed to Issuer's Equity, Forward Rate Per Share	$17.25
Forward Contract Net Settlement Price Per Share	$16.33
Number of Mortgages to Repay	5
Extinguishment of Debt, Amount	129,300,000
Price per share in a public offering									$14.40
Issuance of common shares		3,403,333
Preferred stock, shares authorized	9,000,000
$75.0MillionATM [Domain]
Class of Stock [Line Items]
Common stock authorized through equity offering program	75,000,000
Stock sold	107,498
Gross proceeds from sale of stock				2,000,000
Common Stock, Shares Issued	0
Common Stock
Class of Stock [Line Items]
Stock sold		6,325,000
Gross proceeds from sale of stock		87,200,000
Forward Contract Indexed to Issuer's Equity, Base Common Shares	6,500,000
Forward Contract Indexed to Issuer's Equity, Additional Common Shares Option Exercised	547,958
Forward Contract Indexed to Issuer's Equity, Shares	7,047,958
Forward Contract Sale Net Proceeds	115,100,000
Stock repurchased, shares	3,825,125
Stock repurchased, value	41,100,000
Stock repurchased during period, shares					0
August 2010 At The Market (ATM) Program [Member]
Class of Stock [Line Items]
Common stock authorized through equity offering program		25,000,000
Stock sold		681,178
Gross proceeds from sale of stock		11,100,000
Preferred Stock [Member]
Class of Stock [Line Items]
Stock repurchased, shares	389,500
Stock repurchased, value	7,600,000
Stock repurchased during period, shares						0
Series A Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, shares authorized	3,000,000
Class A Cumulative Redeemable Preferred [Member]
Class of Stock [Line Items]
Preferred stock, shares authorized	225,000
Preferred stock dividend rate, percentage	9.75%
Series B Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, shares authorized	3,000,000
Class B Series I Cumulative Preferred Shares [Member]
Class of Stock [Line Items]
Preferred stock, shares authorized	400,000
Class B Series II Cumulative Redeemable Preferred Shares [Member]
Class of Stock [Line Items]
Preferred stock, shares authorized	232,000
Preferred stock dividend rate, percentage	8.70%
Noncumulative Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, shares authorized	3,000,000
July 2005 and October 06 Stock Repurchase Program [Member]
Class of Stock [Line Items]
Stock repurchase authorized amount								50,000,000
Stock repurchase remaining authorized repurchase amount							1,300,000
December 2008 Stock Repurchase Program [Member]
Class of Stock [Line Items]
Stock repurchase authorized amount							$25,000,000
Restricted Stock [Member]
Class of Stock [Line Items]
Restricted shares vested and issued from treasury shares	175,287

Common_Treasury_and_Preferred_2

Common, Treasury and Preferred Shares (Shareholder Rights Plan) (Details)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2014	Jan. 31, 1999
Class of Warrant or Right [Line Items]
Preferred Stock, Shares Outstanding		0
Stock sold	2,921,667
Shareholders Rights Plan [Member]
Class of Warrant or Right [Line Items]
Purchase price per right			40
Common shares percentage acquired			15.00%
Asset sale percentage			50.00%
Stock sold		0
Class B Series I Cumulative Preferred Shares [Member] | Shareholders Rights Plan [Member]
Class of Warrant or Right [Line Items]
Portion of preferred share per right			0.001

Earnings_Per_Share_Details

Earnings Per Share (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Units remaining	0				0				0		0
Income (loss) from continuing operations									$144,711		$5,288		($119)
Net income attributable to noncontrolling interests									0		-45		-19
Allocation to participating securities									-473		-228		0
Income (loss) from continuing operations applicable to common shares									144,238		5,224		-138
Income from discontinued operations									0		56,007		30,730
Income from discontinued operations applicable to common shares									0		55,798		30,730
Denominator - basic:									57,478,000		51,622,000		46,063,000
Effect of dilutive securities									497,000	[1]	562,000	[1]	0	[1]
Denominator - diluted:									57,975,000		52,184,000		46,063,000
Net income applicable to common shares - basic:
Income from continuing operations applicable to common shares									$2.51		$0.10		$0
Income from discontinued operations									$0		$1.08		$0.66
Net income applicable to common shares - basic	$0.64	$0.06	$1.08	$0.73	$0.51	$0.40	$0.03	$0.21	$2.51		$1.18		$0.66
Net income applicable to common shares - diluted:
Income from continuing operations applicable to common shares									$2.49		$0.10		$0
Income from discontinued operations									$0		$1.07		$0.66
Net income applicable to common shares - diluted	$0.63	$0.06	$1.07	$0.73	$0.51	$0.40	$0.03	$0.20	$2.49		$1.17		$0.66
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount											10,000
Income from discontinued operations [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Allocation to participating securities									0		-209		0
Income from continuing operations [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Allocation to participating securities									($473)		($19)		$0
[1]	For the twelve months ended December 31, 2013, the Company has excluded 10 stock options as their inclusion would be anti-dilutive. For the twelve months ended December 31, 2012, all potential common shares are excluded as they are anti-dilutive to the net loss from continuing operations.

Employee_Benefit_Plans_Details

Employee Benefit Plans (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Medical, Dental, Vision And Life Insurance Benefits [Member]
Employee Benefit Plans [Line Items]
Minimum service period employee eligibility	90 days
Educational Assistance Program and 401K [Member]
Employee Benefit Plans [Line Items]
Minimum service period employee eligibility	6 months
Long Term Disability Coverage [Member]
Employee Benefit Plans [Line Items]
Minimum service period employee eligibility	1 year
401K Plan [Member]
Employee Benefit Plans [Line Items]
Maximum percentage of empoloyee compensation to be matched	50.00%
Employer matching contribution, minimum employee service period	1 year
Employer matching contribution percent of match	25.00%
Matching percentage for employer contributions	6.00%
Expenses related to the defined contribution plan	$170,000	$153,000	$143,000

Employee_Benefit_Plans_Changes

Employee Benefit Plans (Changes in SERP Balances) (Details) (Supplemental Executive Retirement Plan [Member], USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2010
Supplemental Executive Retirement Plan [Member]
Changes in SERP balances [Roll Forward]
Balance at beginning of period	$2,520	$2,283		$2,067
Service cost	80	81	77
Interest cost	174	156	139
Balance at end of period	$2,774	$2,520	$2,283	$2,067

Equity_Based_Award_Plans_Detai

Equity Based Award Plans (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Feb. 05, 2014	4-May-11
	Plan
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Individual annual award limit				500,000
Share-based compensation cost	$3,800,000	$4,600,000	$3,700,000
Share-based compensation in capitalized payroll	450,000	400,000	200,000
Number of compensation plans	2
Options granted			125,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	4,000,000
Aggregate intrinsic value of stock options exercisable	2,400,000
2011 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Common shares available for awards	3,221,120				1,726,608
Newly authorized common shares					1,500,000
2008 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Common shares available for awards					226,608
Restated Equity Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Common shares available for awards				2,700,000
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Nonvested at beginning of period, shares	735,184
Granted, shares	161,267
Vested, shares	175,287
Forfeited, shares	18,304
Nonvested at end of period, shares	702,860	735,184
Nonvested at beginning of period, weighted average grant-date fair value	$10.52
Granted, weighted average grant-date fair value	$16.11	$10.44	$16.48
Vested, weighted average grant-date fair value	$16.39
Forfeited, weighted average grant-date fair value	$11.39
Nonvested at end of period, weighted average grant-date fair value	$10.31	$10.52
Total fair value of restricted shares vested	2,900,000	7,600,000	2,900,000
Total Estimated Grant Date Fair Value Including Deferred Awards	90,000	4,300,000
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Nonvested at beginning of period, shares	34,797
Granted, shares	45,365
Vested, shares	26,603
Forfeited, shares	8,194
Nonvested at end of period, shares	45,365
Nonvested at beginning of period, weighted average grant-date fair value	$17.15
Granted, weighted average grant-date fair value	$17.06
Vested, weighted average grant-date fair value	$17.38
Forfeited, weighted average grant-date fair value	$16.38
Nonvested at end of period, weighted average grant-date fair value	$17.06
Restricted Share and RSU's [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Total fair value of restricted shares vested	460,000	669,000	715,000
Total unrecognized compensation cost related to non-vested restricted share awards and RSU's	$4,700,000
Weighted average period over which to recognize non-vested restricted share awards and RSU's	1 year 10 months
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Options granted	0		125,000

Equity_Based_Award_Plans_Optio

Equity Based Award Plans (Options Outstanding and Exerciseable by Plan) (Details)	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding	360,376	510,020
Options Exerciseable	318,710
2011 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding	61,286
Options Exerciseable	19,620
2001 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding	299,090
Options Exerciseable	299,090

Equity_Based_Award_Plans_Monte

Equity Based Award Plans (Monte Carlo assumptions) (Details)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Risk-free interest rate, minimum	0.02%
Restricted Stock [Member]
Risk-free interest rate, minimum		0.10%
Risk-free interest rate, maximum	0.80%	0.50%
Expected life (performance period)	3 years
AERC [Member] | Restricted Stock [Member]
Expected volatility, minimum	22.30%	18.10%
Expected volatility, maximum	24.20%	22.50%
Peer Group [Member] | Restricted Stock [Member]
Expected volatility, minimum	16.90%	14.70%
Expected volatility, maximum	24.70%	29.50%

Equity_Based_Award_Plans_Black

Equity Based Award Plans (Black Scholes assumptions) (Details) (Stock Options [Member], USD $)	12 Months Ended
	Dec. 31, 2014
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	33.90%
Risk-free interest rate	1.30%
Expected life of options (in years)	7 years
Dividend yield	4.70%
Grant-date fair value	$2.97

Equity_Based_Award_Plans_Stock

Equity Based Award Plans (Stock option detail) (Details) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014
Share-based Compensation [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	$4
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding at beginning of period, shares	510,020
Outstanding at beginning of period, weighted average exercise price	$11.47
Exercised, shares	80,930
Exercised, weighted average exercise price	$9.07
Share-based Compensation Arrangement by Share-Based Payment Award, Options, Forfeited per Settlement, Number of Shares	68,714
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price	$15.20
Outstanding at end of period, shares	360,376
Outstanding at end of period, weighted average exercise price	$11.29
Exerciseable at end of period, shares	318,710
Exercisable at end of period, weighted average exercise price	$10.77
Outstanding at end of period, weighted average remaining contract life	2 years 1 month
Exercisable at end of period, weighted average remaining contract life	1 year 5 months

DirectorExecutive_Compensation1

Director/Executive Compensation (Details) (USD $)	12 Months Ended			0 Months Ended	3 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Feb. 02, 2010	Mar. 31, 2013
Base Salary [Member] | Elective Deferred Compensation Program [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Plan deferral percentage	90.00%
Incentive Bonus [Member] | Elective Deferred Compensation Program [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Plan deferral percentage	100.00%
Director [Member] | Deferred Compensation, Share-based Payments [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Share equivalent units, deferred	318,075
Deferred director fees, share equivalent units	95,060
Deferred Compensation Arrangement With Individual, Deferred Director Shares	129,116
Deferred Compensation Arrangement With Individual, Deferred Director Dividends	93,898
Distributions from plan in cash		$45,000	$45,000
Distribution from plan in shares	8,789	20,651	59,988
Officer [Member] | Deferred Compensation, Share-based Payments [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Distribution from plan in shares	5,407
Officer [Member] | Long Term Incentive Plan Single Year Component [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Annual Incentives Earned	1,600,000	1,800,000	2,100,000
Immediately vested portion of shares	33.30%
Remaining vesting portion of shares	66.70%
Officer [Member] | Long Term Incentive Plan Multi Year Component [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Measurement period	3 years
Frequency metrics and objectives are established	3 years
Officer [Member] | Long Term Incentive Plan Multi Year Component [Member] | Restricted Stock [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Grant of restricted shares issued	3,300,000			3,900,000	7,100,000
Officer [Member] | Incentive Bonus [Member] | Annual Incentives Plan [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Annual Incentives Earned	1,800,000	$2,000,000	$1,900,000
Restricted Stock [Member] | Elective Deferred Compensation Program [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Deferred Compensation Arrangement with Individual, Share Equivalent Units Deferred	323,105	307,207
Share equivalent units, deferred	238,535	235,786
Deferred Compensation Arrangement with Individual, Dividend Units Deferred	84,750	71,421

Subsequent_Events_Details

Subsequent Events (Details) (USD $)

0 Months Ended

12 Months Ended

0 Months Ended

Dec. 30, 2014

Dec. 03, 2014

Nov. 03, 2014

Aug. 01, 2014

1-May-14

Feb. 03, 2014

Nov. 01, 2013

Aug. 01, 2013

1-May-13

Feb. 01, 2013

Nov. 01, 2012

Aug. 01, 2012

1-May-12

Feb. 01, 2012

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Jan. 01, 2016

Jan. 30, 2015

Jan. 01, 2020

Jan. 01, 2018

Subsequent Event [Line Items]

Equity interest

50.00%

Forward starting interest rate swap date

19-Dec-11

Credit spread

1.40%

Derivative effective date

7-Jun-13

All-in rate

2.66%

Dividends

$0.20

$0.19

$0.19

$0.19

$0.19

$0.19

$0.19

$0.19

$0.18

$0.18

$0.18

$0.17

$0.79

$0.76

$0.71

Dividend record date

30-Dec-14

Dividend declaration date

3-Dec-14

$25 million [Member]

Subsequent Event [Line Items]

Forward starting interest rate swap date

30-Jan-15

Notional amount

$25,000,000

Credit spread

1.40%

Derivative effective date

1-Jan-16

Fixed derivative rate

1.42%

All-in rate

2.82%

$125 million [Member]

Subsequent Event [Line Items]

Notional amount

125,000,000

Debt face amount

150,000,000

Derivative effective date

1-Jan-18

Fixed derivative rate

1.75%

All-in rate

3.15%

Derivative, Maturity Date

1-Jan-20

Dividend Paid [Member]

Subsequent Event [Line Items]

Dividends payment date

30-Jan-15

Dividends

$0.21

Future Development [Member] | 5th and Huntington [Member]

Subsequent Event [Line Items]

Equity interest

50.00%

[1]

Payment for partners interest

$8,400,000

Equity interest in partnership

100.00%

[1]

5th and Huntington is an unconsolidated development project as of December 31, 2014. On February 3, 2015, we purchased our partner's 50.0% interest in the partnership for $8.4 million, increasing our ownership percentage in the development to 100%. See Note 19 for further information related to this subsequent event.

Quarterly_Financial_Informatio2

Quarterly Financial Information (Unaudited) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenue	$48,256				$49,070				$194,080	$181,479	$158,553
Operating income	10,336	9,805	9,031	8,260	9,795	8,963	8,322	7,550	37,433	34,630	29,154
Net income	36,672	3,418	62,348	42,273	29,273	20,007	1,652	10,363	144,711	61,295	30,611
Net income attributable to AERC	36,672	3,418	62,348	42,273	29,273	19,993	1,638	10,346	144,711	61,250	30,592
Basic earnings per common share	$0.64	$0.06	$1.08	$0.73	$0.51	$0.40	$0.03	$0.21	$2.51	$1.18	$0.66
Diluted earnings per common share	$0.63	$0.06	$1.07	$0.73	$0.51	$0.40	$0.03	$0.20	$2.49	$1.17	$0.66
Scenario, Previously Reported [Member]
Revenue		$48,207	$47,902	$49,715		$46,069	$43,484	$42,856

Schedule_II_Valuation_and_Qual1

Schedule II - Valuation and Qualifying Accounts (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Allowance for doubtful accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$78		$104		$141
Charged to Costs and Expenses	1,657	[1]	1,823	[1]	1,991	[1]
Charged to Other Accounts	0		0		0
Deductions	-1,666	[2]	-1,849	[2]	-2,028	[2]
Balance at End of Period	69		78		104
Valuation allowance-deferred tax asset
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	6,632		6,626		5,970
Charged to Costs and Expenses	38	[1]	6	[1]	656	[1]
Charged to Other Accounts	0		0		0
Deductions	0	[2]	0	[2]	0	[2]
Balance at End of Period	$6,670		$6,632		$6,626
[1]	Adjustments to the valuation allowance for deferred taxes are recorded to adjust deferred tax asset to net realizable value.
[2]	Includes the write-off of uncollectible balances, net of any subsequent recoveries received from tenants.

Schedule_III_Real_Estate_and_A1

Schedule III - Real Estate and Accumulated Depreciation (Details) (USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Real Estate and Accumulated Depreciation [Line Items]
Costs Capitalized Subsequent to Acquisition	143,770,000
Total, Gross	1,723,837,000		1,751,519,000	1,511,647,000	1,345,439,000
Accumulated Depreciation, Gross	397,210,000		386,841,000	371,730,000	358,605,000
Furniture and fixtures	41,609,000		39,725,000
Construction in progress	73,581,000		42,793,000
Real Estate Investment Property, at Cost	1,723,837,000		1,751,519,000
Real Estate Investment Property, Accumulated Depreciation	397,210,000		386,841,000
Aggregate cost for federal income tax purposes	1,500,000,000
Multifamily Properties [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	259,918,000
Buildings & Improvements, Cost	1,204,961,000
Costs Capitalized Subsequent to Acquisition	136,628,000
Land, Gross	260,832,000
Buildings & Improvements, Gross	1,341,232,000
Total, Gross	1,602,064,000
Accumulated Depreciation, Gross	367,481,000
Encumbrances	272,613,000
Mallard's Crossing [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	941,000
Buildings & Improvements, Cost	8,499,000
Costs Capitalized Subsequent to Acquisition	3,141,000
Land, Gross	941,000
Buildings & Improvements, Gross	11,640,000
Total, Gross	12,581,000
Accumulated Depreciation, Gross	7,434,000
Encumbrances	0	[1]
The Residence at Barrington [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	2,357,000
Buildings & Improvements, Cost	21,986,000
Costs Capitalized Subsequent to Acquisition	2,114,000
Land, Gross	2,355,000
Buildings & Improvements, Gross	24,100,000
Total, Gross	26,455,000
Accumulated Depreciation, Gross	13,305,000
Encumbrances	0	[1]
Village at Avon [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	2,145,000
Buildings & Improvements, Cost	21,704,000
Costs Capitalized Subsequent to Acquisition	3,134,000
Land, Gross	2,145,000
Buildings & Improvements, Gross	24,838,000
Total, Gross	26,983,000
Accumulated Depreciation, Gross	12,139,000
Encumbrances	19,560,000	[1]
Village of Western Reserve [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	691,000
Buildings & Improvements, Cost	6,866,000
Costs Capitalized Subsequent to Acquisition	860,000
Land, Gross	691,000
Buildings & Improvements, Gross	7,726,000
Total, Gross	8,417,000
Accumulated Depreciation, Gross	4,069,000
Encumbrances	0	[1]
Westchester Townhomes [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	693,000
Buildings & Improvements, Cost	5,686,000
Costs Capitalized Subsequent to Acquisition	1,293,000
Land, Gross	693,000
Buildings & Improvements, Gross	6,979,000
Total, Gross	7,672,000
Accumulated Depreciation, Gross	5,860,000
Encumbrances	0	[1]
Westlake Seven [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	559,000
Buildings & Improvements, Cost	332,000
Costs Capitalized Subsequent to Acquisition	349,000
Land, Gross	559,000
Buildings & Improvements, Gross	1,240,000
Total, Gross	1,799,000
Accumulated Depreciation, Gross	1,166,000
Encumbrances	0	[1]
Williamsburg Townhomes [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	844,000
Buildings & Improvements, Cost	12,787,000
Costs Capitalized Subsequent to Acquisition	4,083,000
Land, Gross	844,000
Buildings & Improvements, Gross	16,870,000
Total, Gross	17,714,000
Accumulated Depreciation, Gross	11,215,000
Encumbrances	0	[1]
Bedford Commons [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	929,000
Buildings & Improvements, Cost	5,751,000
Costs Capitalized Subsequent to Acquisition	1,124,000
Land, Gross	929,000
Buildings & Improvements, Gross	6,875,000
Total, Gross	7,804,000
Accumulated Depreciation, Gross	4,447,000
Encumbrances	0	[1]
Heathermoor [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	1,796,000
Buildings & Improvements, Cost	8,535,000
Costs Capitalized Subsequent to Acquisition	2,194,000
Land, Gross	1,796,000
Buildings & Improvements, Gross	10,729,000
Total, Gross	12,525,000
Accumulated Depreciation, Gross	7,175,000
Encumbrances	0	[1]
Kensington Grove [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	533,000
Buildings & Improvements, Cost	4,600,000
Costs Capitalized Subsequent to Acquisition	936,000
Land, Gross	533,000
Buildings & Improvements, Gross	5,536,000
Total, Gross	6,069,000
Accumulated Depreciation, Gross	3,386,000
Encumbrances	0	[1]
Lake Forest [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	824,000
Buildings & Improvements, Cost	6,135,000
Costs Capitalized Subsequent to Acquisition	1,124,000
Land, Gross	824,000
Buildings & Improvements, Gross	7,259,000
Total, Gross	8,083,000
Accumulated Depreciation, Gross	4,765,000
Encumbrances	0	[1]
Perimeter Lakes [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	1,265,000
Buildings & Improvements, Cost	8,647,000
Costs Capitalized Subsequent to Acquisition	1,574,000
Land, Gross	1,265,000
Buildings & Improvements, Gross	10,221,000
Total, Gross	11,486,000
Accumulated Depreciation, Gross	6,340,000
Encumbrances	0	[1]
Saw Mill Village [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	2,548,000
Buildings & Improvements, Cost	17,218,000
Costs Capitalized Subsequent to Acquisition	4,664,000
Land, Gross	2,548,000
Buildings & Improvements, Gross	21,882,000
Total, Gross	24,430,000
Accumulated Depreciation, Gross	12,957,000
Encumbrances	15,930,000	[1]
Sterling Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	646,000
Buildings & Improvements, Cost	3,919,000
Costs Capitalized Subsequent to Acquisition	725,000
Land, Gross	646,000
Buildings & Improvements, Gross	4,644,000
Total, Gross	5,290,000
Accumulated Depreciation, Gross	2,978,000
Encumbrances	0	[1]
The Residence at Christopher Wren [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	1,560,000
Buildings & Improvements, Cost	13,754,000
Costs Capitalized Subsequent to Acquisition	4,000,000
Land, Gross	1,560,000
Buildings & Improvements, Gross	17,754,000
Total, Gross	19,314,000
Accumulated Depreciation, Gross	11,751,000
Encumbrances	0	[1]
Wyndemere Land [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	200,000
Buildings & Improvements, Cost	0
Costs Capitalized Subsequent to Acquisition	0
Land, Gross	200,000
Buildings & Improvements, Gross	0
Total, Gross	200,000
Accumulated Depreciation, Gross	0
Encumbrances	0	[1]
Arbor Landings [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	1,129,000
Buildings & Improvements, Cost	10,403,000
Costs Capitalized Subsequent to Acquisition	11,141,000
Land, Gross	1,682,000
Buildings & Improvements, Gross	20,991,000
Total, Gross	22,673,000
Accumulated Depreciation, Gross	12,279,000
Encumbrances	0	[1]
Clinton Place [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	1,219,000
Buildings & Improvements, Cost	9,478,000
Costs Capitalized Subsequent to Acquisition	2,486,000
Land, Gross	1,219,000
Buildings & Improvements, Gross	11,964,000
Total, Gross	13,183,000
Accumulated Depreciation, Gross	6,981,000
Encumbrances	0	[1]
Georgetown Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	1,778,000
Buildings & Improvements, Cost	12,141,000
Costs Capitalized Subsequent to Acquisition	14,270,000
Land, Gross	2,128,000
Buildings & Improvements, Gross	26,061,000
Total, Gross	28,189,000
Accumulated Depreciation, Gross	16,148,000
Encumbrances	0	[1]
Oaks at Hampton [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	3,026,000
Buildings & Improvements, Cost	27,204,000
Costs Capitalized Subsequent to Acquisition	5,023,000
Land, Gross	3,026,000
Buildings & Improvements, Gross	32,227,000
Total, Gross	35,253,000
Accumulated Depreciation, Gross	20,964,000
Encumbrances	0	[1]
Spring Valley [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	1,433,000
Buildings & Improvements, Cost	13,461,000
Costs Capitalized Subsequent to Acquisition	2,156,000
Land, Gross	1,433,000
Buildings & Improvements, Gross	15,617,000
Total, Gross	17,050,000
Accumulated Depreciation, Gross	8,776,000
Encumbrances	0	[1]
Landings at the Preserve [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	1,081,000
Buildings & Improvements, Cost	7,190,000
Costs Capitalized Subsequent to Acquisition	1,571,000
Land, Gross	1,143,000
Buildings & Improvements, Gross	8,699,000
Total, Gross	9,842,000
Accumulated Depreciation, Gross	5,392,000
Encumbrances	0	[1]
Summer Ridge [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	1,251,000
Buildings & Improvements, Cost	11,194,000
Costs Capitalized Subsequent to Acquisition	2,827,000
Land, Gross	1,251,000
Buildings & Improvements, Gross	14,021,000
Total, Gross	15,272,000
Accumulated Depreciation, Gross	8,398,000
Encumbrances	0	[1]
Doral West [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	12,060,000	[2]
Buildings & Improvements, Cost	79,513,000	[2]
Costs Capitalized Subsequent to Acquisition	3,464,000	[2]
Land, Gross	12,060,000	[2]
Buildings & Improvements, Gross	82,977,000	[2]
Total, Gross	95,037,000	[2]
Accumulated Depreciation, Gross	5,062,000	[2]
Encumbrances	0	[1],[2]
Vista Lago [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	4,012,000	[2]
Buildings & Improvements, Cost	35,954,000	[2]
Costs Capitalized Subsequent to Acquisition	688,000	[2]
Land, Gross	4,012,000	[2]
Buildings & Improvements, Gross	36,642,000	[2]
Total, Gross	40,654,000	[2]
Accumulated Depreciation, Gross	13,041,000	[2]
Encumbrances	0	[1],[2]
Waterstone at Wellington [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	5,948,000	[2]
Buildings & Improvements, Cost	25,456,000	[2]
Costs Capitalized Subsequent to Acquisition	773,000	[2]
Land, Gross	5,948,000	[2]
Buildings & Improvements, Gross	26,229,000	[2]
Total, Gross	32,177,000	[2]
Accumulated Depreciation, Gross	3,781,000	[2]
Encumbrances	0	[1],[2]
Windsor Pines [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	4,834,000
Buildings & Improvements, Cost	28,795,000
Costs Capitalized Subsequent to Acquisition	1,843,000
Land, Gross	4,834,000
Buildings & Improvements, Gross	30,638,000
Total, Gross	35,472,000
Accumulated Depreciation, Gross	16,822,000
Encumbrances	0	[1]
Cambridge at Buckhead [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	6,166,000	[2]
Buildings & Improvements, Cost	16,730,000	[2]
Costs Capitalized Subsequent to Acquisition	1,142,000	[2]
Land, Gross	6,166,000	[2]
Buildings & Improvements, Gross	17,872,000	[2]
Total, Gross	24,038,000	[2]
Accumulated Depreciation, Gross	6,015,000	[2]
Encumbrances	0	[3]
Morgan Place [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	3,292,000
Buildings & Improvements, Cost	9,159,000
Costs Capitalized Subsequent to Acquisition	1,710,000
Land, Gross	3,292,000
Buildings & Improvements, Gross	10,869,000
Total, Gross	14,161,000
Accumulated Depreciation, Gross	5,790,000
Encumbrances	0	[1]
7001 Arlington at Bethesda [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	12,650,000	[3]
Buildings & Improvements, Cost	0	[3]
Costs Capitalized Subsequent to Acquisition	0	[3]
Land, Gross	12,650,000	[3]
Buildings & Improvements, Gross	0	[3]
Total, Gross	12,650,000	[3]
Accumulated Depreciation, Gross	0	[3]
Encumbrances	16,673,000	[1],[3]
Dwell Vienna Metro [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	11,241,000	[2]
Buildings & Improvements, Cost	67,130,000	[2]
Costs Capitalized Subsequent to Acquisition	277,000	[2]
Land, Gross	11,241,000	[2]
Buildings & Improvements, Gross	67,407,000	[2]
Total, Gross	78,648,000	[2]
Accumulated Depreciation, Gross	8,593,000	[2]
Encumbrances	41,167,000	[1],[2]
Center Point [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	1,508,000
Buildings & Improvements, Cost	22,861,000
Costs Capitalized Subsequent to Acquisition	2,593,000
Land, Gross	1,470,000
Buildings & Improvements, Gross	25,492,000
Total, Gross	26,962,000
Accumulated Depreciation, Gross	14,772,000
Encumbrances	0	[1]
Residence at White River [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	1,064,000
Buildings & Improvements, Cost	11,631,000
Costs Capitalized Subsequent to Acquisition	2,579,000
Land, Gross	1,064,000
Buildings & Improvements, Gross	14,210,000
Total, Gross	15,274,000
Accumulated Depreciation, Gross	8,192,000
Encumbrances	0	[1]
Steeplechase at Shiloh [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	2,261,000
Buildings & Improvements, Cost	16,257,000
Costs Capitalized Subsequent to Acquisition	1,237,000
Land, Gross	2,261,000
Buildings & Improvements, Gross	17,494,000
Total, Gross	19,755,000
Accumulated Depreciation, Gross	9,501,000
Encumbrances	0	[1]
Lofts at Weston Lakeside [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	4,112,000	[2]
Buildings & Improvements, Cost	33,105,000	[2]
Costs Capitalized Subsequent to Acquisition	26,000	[2]
Land, Gross	4,112,000	[2]
Buildings & Improvements, Gross	33,131,000	[2]
Total, Gross	37,243,000	[2]
Accumulated Depreciation, Gross	1,591,000	[2]
Encumbrances	0	[1],[2]
Southpoint Village [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	3,307,000	[2]
Buildings & Improvements, Cost	29,661,000	[2]
Costs Capitalized Subsequent to Acquisition	163,000	[2]
Land, Gross	3,307,000	[2]
Buildings & Improvements, Gross	29,824,000	[2]
Total, Gross	33,131,000	[2]
Accumulated Depreciation, Gross	2,955,000	[2]
Encumbrances	0	[1],[2]
St. Mary's Square [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	3,065,000	[2]
Buildings & Improvements, Cost	23,481,000	[2]
Costs Capitalized Subsequent to Acquisition	29,000	[2]
Land, Gross	3,065,000	[2]
Buildings & Improvements, Gross	23,510,000	[2]
Total, Gross	26,575,000	[2]
Accumulated Depreciation, Gross	1,049,000	[2]
Encumbrances	0	[1],[2]
The Apartments at the Arboretum [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	4,008,000	[2]
Buildings & Improvements, Cost	33,411,000	[2]
Costs Capitalized Subsequent to Acquisition	565,000	[2]
Land, Gross	4,008,000	[2]
Buildings & Improvements, Gross	33,976,000	[2]
Total, Gross	37,984,000	[2]
Accumulated Depreciation, Gross	3,589,000	[2]
Encumbrances	0	[1],[2]
The Park at Crossroads [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	5,520,000	[2]
Buildings & Improvements, Cost	31,391,000	[2]
Costs Capitalized Subsequent to Acquisition	800,000	[2]
Land, Gross	5,520,000	[2]
Buildings & Improvements, Gross	32,191,000	[2]
Total, Gross	37,711,000	[2]
Accumulated Depreciation, Gross	3,414,000	[2]
Encumbrances	25,246,000	[1],[2]
Alpha Mill Phase I and Phase II [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	8,140,000	[2]
Buildings & Improvements, Cost	36,044,000	[2]
Costs Capitalized Subsequent to Acquisition	119,000	[2]
Land, Gross	8,140,000	[2]
Buildings & Improvements, Gross	36,163,000	[2]
Total, Gross	44,303,000	[2]
Accumulated Depreciation, Gross	769,000	[2]
Encumbrances	0	[1],[2]
The Apartments at Blakeney [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	5,430,000	[2]
Buildings & Improvements, Cost	46,013,000	[2]
Costs Capitalized Subsequent to Acquisition	216,000	[2]
Land, Gross	5,430,000	[2]
Buildings & Improvements, Gross	46,229,000	[2]
Total, Gross	51,659,000	[2]
Accumulated Depreciation, Gross	2,457,000	[2]
Encumbrances	27,560,000	[1],[2]
Ashborough [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	20,136,000	[2]
Buildings & Improvements, Cost	65,885,000	[2]
Costs Capitalized Subsequent to Acquisition	802,000	[2]
Land, Gross	20,136,000	[2]
Buildings & Improvements, Gross	66,687,000	[2]
Total, Gross	86,823,000	[2]
Accumulated Depreciation, Gross	10,967,000	[2]
Encumbrances	47,591,000	[1],[2]
Riverside Station [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	13,680,000	[2]
Buildings & Improvements, Cost	38,708,000	[2]
Costs Capitalized Subsequent to Acquisition	664,000	[2]
Land, Gross	13,680,000	[2]
Buildings & Improvements, Gross	39,372,000	[2]
Total, Gross	53,052,000	[2]
Accumulated Depreciation, Gross	6,820,000	[2]
Encumbrances	34,855,000	[1],[2]
Westwind Farms [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	18,265,000	[2]
Buildings & Improvements, Cost	67,098,000	[2]
Costs Capitalized Subsequent to Acquisition	802,000	[2]
Land, Gross	18,265,000	[2]
Buildings & Improvements, Gross	67,900,000	[2]
Total, Gross	86,165,000	[2]
Accumulated Depreciation, Gross	10,684,000	[2]
Encumbrances	0	[1],[2]
River Forest [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	4,655,000	[2]
Buildings & Improvements, Cost	25,758,000	[2]
Costs Capitalized Subsequent to Acquisition	7,314,000	[2]
Land, Gross	4,645,000	[2]
Buildings & Improvements, Gross	33,083,000	[2]
Total, Gross	37,728,000	[2]
Accumulated Depreciation, Gross	8,018,000	[2]
Encumbrances	0	[1],[2]
The Alexander at Ghent [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	4,368,000	[2]
Buildings & Improvements, Cost	43,263,000	[2]
Costs Capitalized Subsequent to Acquisition	1,275,000	[2]
Land, Gross	4,367,000	[2]
Buildings & Improvements, Gross	44,538,000	[2]
Total, Gross	48,905,000	[2]
Accumulated Depreciation, Gross	12,515,000	[2]
Encumbrances	0	[1],[2]
The Belvedere [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	6,044,000	[2]
Buildings & Improvements, Cost	35,353,000	[2]
Costs Capitalized Subsequent to Acquisition	572,000	[2]
Land, Gross	6,044,000	[2]
Buildings & Improvements, Gross	35,925,000	[2]
Total, Gross	41,969,000	[2]
Accumulated Depreciation, Gross	8,898,000	[2]
Encumbrances	0	[1],[2]
Desmond's Tower [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	7,390,000	[2],[4]
Buildings & Improvements, Cost	10,615,000	[2],[4]
Costs Capitalized Subsequent to Acquisition	0	[2],[4]
Land, Gross	7,390,000	[2],[4]
Buildings & Improvements, Gross	10,615,000	[2],[4]
Total, Gross	18,005,000	[2],[4]
Accumulated Depreciation, Gross	1,171,000	[2],[4]
Encumbrances	0	[1],[2],[4]
The Desmond on Wilshire [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	17,491,000	[3]
Buildings & Improvements, Cost	0	[3]
Costs Capitalized Subsequent to Acquisition	0	[3]
Land, Gross	17,491,000	[3]
Buildings & Improvements, Gross	0	[3]
Total, Gross	17,491,000	[3]
Accumulated Depreciation, Gross	0	[3]
Encumbrances	0	[1],[3]
Warner Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	16,139,000	[3]
Buildings & Improvements, Cost	0	[3]
Costs Capitalized Subsequent to Acquisition	0	[3]
Land, Gross	16,139,000	[5]
Buildings & Improvements, Gross	0	[5]
Total, Gross	16,139,000	[5]
Accumulated Depreciation, Gross	0	[5]
Encumbrances	0	[1],[5]
Cantabria at Turtle Creek [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	6,983,000	[3]
Buildings & Improvements, Cost	0	[3]
Costs Capitalized Subsequent to Acquisition	33,242,000	[3]
Land, Gross	6,983,000	[3]
Buildings & Improvements, Gross	33,242,000	[3]
Total, Gross	40,225,000	[3]
Accumulated Depreciation, Gross	317,000	[3]
Encumbrances	32,006,000	[1],[3]
Rienzi at Turtle Creek [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	3,911,000	[2]
Buildings & Improvements, Cost	43,680,000	[2]
Costs Capitalized Subsequent to Acquisition	302,000	[2]
Land, Gross	3,911,000	[2]
Buildings & Improvements, Gross	43,982,000	[2]
Total, Gross	47,893,000	[2]
Accumulated Depreciation, Gross	2,084,000	[2]
Encumbrances	0	[1],[2]
San Raphael [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	3,777,000	[2]
Buildings & Improvements, Cost	15,795,000	[2]
Costs Capitalized Subsequent to Acquisition	1,278,000	[2]
Land, Gross	3,777,000	[2]
Buildings & Improvements, Gross	17,073,000	[2]
Total, Gross	20,850,000	[2]
Accumulated Depreciation, Gross	2,967,000	[2]
Encumbrances	0	[1],[2]
San Raphael Phase II [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	733,000
Buildings & Improvements, Cost	12,263,000
Costs Capitalized Subsequent to Acquisition	0
Land, Gross	733,000
Buildings & Improvements, Gross	12,263,000
Total, Gross	12,996,000
Accumulated Depreciation, Gross	840,000
Encumbrances	0	[1]
The Brixton [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	2,867,000	[2]
Buildings & Improvements, Cost	17,638,000	[2]
Costs Capitalized Subsequent to Acquisition	803,000	[2]
Land, Gross	2,867,000	[2]
Buildings & Improvements, Gross	18,441,000	[2]
Total, Gross	21,308,000	[2]
Accumulated Depreciation, Gross	2,432,000	[2]
Encumbrances	12,025,000	[1],[2]
21 Forty Medical District [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Cost	5,413,000	[2]
Buildings & Improvements, Cost	44,823,000	[2]
Costs Capitalized Subsequent to Acquisition	561,000	[2]
Land, Gross	5,413,000	[2]
Buildings & Improvements, Gross	45,384,000	[2]
Total, Gross	50,797,000	[2]
Accumulated Depreciation, Gross	4,450,000	[2]
Encumbrances	0	[1],[2]
Miscellaneous [Member]
Real Estate and Accumulated Depreciation [Line Items]
Costs Capitalized Subsequent to Acquisition	7,142,000
Land, Gross	945,000
Buildings & Improvements, Gross	5,638,000
Total, Gross	6,583,000
Accumulated Depreciation, Gross	3,079,000
Land, Buildings and Improvements [Member]
Real Estate and Accumulated Depreciation [Line Items]
Land, Gross	261,777,000
Buildings & Improvements, Gross	1,346,870,000
Total, Gross	1,608,647,000
Accumulated Depreciation, Gross	370,560,000
Minimum [Member] | Mallard's Crossing [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | The Residence at Barrington [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | Village at Avon [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | Village of Western Reserve [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | Westchester Townhomes [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | Westlake Seven [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | Williamsburg Townhomes [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | Bedford Commons [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | Heathermoor [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | Kensington Grove [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | Lake Forest [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | Perimeter Lakes [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | Saw Mill Village [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | Sterling Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | The Residence at Christopher Wren [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | Arbor Landings [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | Clinton Place [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | Georgetown Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | Oaks at Hampton [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | Spring Valley [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | Landings at the Preserve [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | Summer Ridge [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | Vista Lago [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | Waterstone at Wellington [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | Windsor Pines [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | Cambridge at Buckhead [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | Morgan Place [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | Dwell Vienna Metro [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | Center Point [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | Residence at White River [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | Steeplechase at Shiloh [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | Southpoint Village [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | The Apartments at the Arboretum [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | The Park at Crossroads [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | Ashborough [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | Riverside Station [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | Westwind Farms [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | River Forest [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | The Alexander at Ghent [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | The Belvedere [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | Desmond's Tower [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	14 years
Minimum [Member] | San Raphael [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | San Raphael Phase II [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | The Brixton [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | 21 Forty Medical District [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	5 years
Minimum [Member] | Miscellaneous [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	10 years
Maximum [Member] | Mallard's Crossing [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | The Residence at Barrington [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | Village at Avon [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | Village of Western Reserve [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | Westchester Townhomes [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | Westlake Seven [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | Williamsburg Townhomes [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | Bedford Commons [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | Heathermoor [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | Kensington Grove [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | Lake Forest [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | Perimeter Lakes [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | Saw Mill Village [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | Sterling Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | The Residence at Christopher Wren [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | Arbor Landings [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | Clinton Place [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | Georgetown Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | Oaks at Hampton [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | Spring Valley [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | Landings at the Preserve [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | Summer Ridge [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | Vista Lago [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | Waterstone at Wellington [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | Windsor Pines [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | Cambridge at Buckhead [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | Morgan Place [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | Dwell Vienna Metro [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | Center Point [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | Residence at White River [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | Steeplechase at Shiloh [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | Southpoint Village [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | The Apartments at the Arboretum [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | The Park at Crossroads [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | Ashborough [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | Riverside Station [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | Westwind Farms [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | River Forest [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | The Alexander at Ghent [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | The Belvedere [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | Desmond's Tower [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | San Raphael [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | San Raphael Phase II [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | The Brixton [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | 21 Forty Medical District [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Maximum [Member] | Miscellaneous [Member]
Real Estate and Accumulated Depreciation [Line Items]
Depreciable Lives - Years	30 years
Furniture and Fixtures [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate Investment Property, Accumulated Depreciation	26,650,000
Desmond's Tower [Member]
Real Estate and Accumulated Depreciation [Line Items]
Square feet of space	78,800
[1]	Encumbrances include mortgage debt collateralized by the real estate assets.
[2]	For acquisitions initiated after June 30, 2001, intangible assets such as in place leases were recognized upon the acquisition of these properties and are not included in the initial costs or historical costs shown.
[3]	Currently under development.
[4]	Commercial building containing 78,800 total square feet.
[5]	Future development project.

Schedule_III_Real_Estate_and_A2

Schedule III - Real Estate and Accumulated Depreciation (Real Estate and Accumulated Depreciation Reconciliation) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, beginning of period	$1,751,519	$1,511,647	$1,345,439
Disposal of fixed assets	-179,655	-124,684	-75,770
New acquisition of properties	45,075	257,683	178,864
Improvements	106,898	106,873	63,114
Balance, end of period	1,723,837	1,751,519	1,511,647
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, beginning of period	386,841	371,730	358,605
Disposal of fixed assets	-49,905	-40,844	-37,531
Depreciation for period	60,274	55,955	50,656
Balance, end of period	$397,210	$386,841	$371,730