Elme Communities (ELME) 10-K 21 Feb 17 2016 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2016	Feb. 16, 2017	Jun. 30, 2016
Document and Entity Information [Abstract]
Entity Registrant Name	WASHINGTON REAL ESTATE INVESTMENT TRUST
Entity Central Index Key	104,894
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		74,711,571
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 2,304,199,990

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Assets
Land	$ 573,315	$ 561,256
Income producing property	2,112,088	2,076,541
Real estate investment property, at cost	2,685,403	2,637,797
Accumulated depreciation and amortization	(657,425)	(692,608)
Net income producing property	2,027,978	1,945,189
Properties under development or held for future development	40,232	36,094
Total real estate held for investment, net	2,068,210	1,981,283
Cash and cash equivalents	11,305	23,825
Restricted cash	6,317	13,383
Rents and other receivables, net of allowance for doubtful accounts of $2,377 and $2,297, respectively	64,319	62,890
Prepaid expenses and other assets	103,468	109,787
Total assets	2,253,619	2,191,168
Liabilities
Notes payable, net	843,084	743,181
Mortgage notes payable, net	148,540	418,052
Lines of credit	120,000	105,000
Accounts payable and other liabilities	46,967	45,367
Dividends payable	22,414	20,434
Advance rents	11,750	12,744
Tenant security deposits	8,802	9,378
Total liabilities	1,201,557	1,354,156
Shareholders' equity
Preferred shares; $0.01 par value; 10,000 shares authorized; no shares issued or outstanding	0	0
Shares of beneficial interest; $0.01 par value; 100,000 shares authorized: 74,606 and 68,191 shares issued and outstanding at December 31, 2016 and 2015, respectively	746	682
Additional paid in capital	1,368,636	1,193,298
Distributions in excess of net income	(326,047)	(357,781)
Accumulated other comprehensive income (loss)	7,611	(550)
Total shareholders’ equity	1,050,946	835,649
Noncontrolling interests in subsidiary	1,116	1,363
Total equity	1,052,062	837,012
Total liabilities and equity	$ 2,253,619	$ 2,191,168

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Rents and receivables, allowance for doubtful accounts	$ 2,377	$ 2,297
Preferred shares, par value	$ 0.01	$ 0.01
Preferred shares, shares authorized	10,000	10,000
Preferred shares, shares issued	0	0
Preferred shares, shares outstanding	0	0
Shares of beneficial interest, issued	74,606	68,191
Shares of beneficial interest, par value	$ 0.01	$ 0.01
Shares of beneficial interest, authorized	100,000	100,000
Shares of beneficial interest, shares outstanding	74,606	68,191

Consolidated Statements Of Inco

Consolidated Statements Of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue
Real estate rental revenue	$ 313,264	$ 306,427	$ 288,637
Expenses
Real estate expenses	115,013	112,234	103,695
Depreciation and amortization	108,406	108,935	96,011
Acquisition costs	1,178	2,056	5,710
Casualty (gain) and real estate impairment loss, net	(676)	5,909	0
General and administrative	19,545	20,123	19,644
Total expenses	243,466	249,257	225,060
Gain on sale of real estate, continuing operations	101,704	91,107	570
Real estate operating income	171,502	148,277	64,147
Other income (expense)
Interest expense	(53,126)	(59,546)	(59,785)
Other income	297	709	825
Loss on extinguishment of debt	0	(119)	0
Income tax benefit (expense)	615	(134)	(117)
Total other income (expense)	(52,214)	(59,090)	(59,077)
Income from continuing operations	119,288	89,187	5,070
Discontinued operations:
Income from operations of properties sold or held for sale	0	0	546
Gain on sale of real estate, discontinued operations	0	0	105,985
Net income	119,288	89,187	111,601
Less: Net loss attributable to noncontrolling interests in subsidiaries	(51)	(553)	(38)
Net income attributable to the controlling interests	$ 119,339	$ 89,740	$ 111,639
Basic net income attributable to the controlling interests per share
Continuing operations	$ 1.65	$ 1.31	$ 0.08
Discontinued operations, including gain on sale of real estate	0	0	1.59
Net income attributable to the controlling interests per share	1.65	1.31	1.67
Diluted net income attributable to the controlling interests per share
Continuing operations	1.65	1.31	0.08
Discontinued operations, including gain on sale of real estate	0	0	1.59
Net income attributable to the controlling interests per share	$ 1.65	$ 1.31	$ 1.67
Weighted average shares outstanding – basic	72,163	68,177	66,795
Weighted average shares outstanding – diluted	72,339	68,310	66,837

Consolidated Statements Of Shar

Consolidated Statements Of Shareholders' Equity - USD ($) $ in Thousands	Total	Shares Of Beneficial Interest At Par Value [Member]	Additional Paid In Capital [Member]	Distributions In Excess Of Net Income Attributable To The Controlling Interests [Member]	AOCI Attributable to Parent [Member]	Total Shareholders' Equity [Member]	Noncontrolling Interests In Subsidiaries [Member]
Balance, shares at Dec. 31, 2013		66,531,000
Balance at Dec. 31, 2013	$ 759,446	$ 665	$ 1,151,174	$ (396,880)	$ 0	$ 754,959	$ 4,487
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to the controlling interests	111,639			111,639		111,639
Net loss attributable to noncontrolling interests	(38)						(38)
Distributions to noncontrolling interests	(1,784)						(1,784)
Contributions from noncontrolling interest	9						9
Dividends	(80,277)			(80,277)		(80,277)
Stock issued during period (in shares)		1,125,000
Equity offerings, net of issuance costs	30,690	$ 11	30,679			30,690
Share grants, net of share grant amortization and forfeitures (in shares)		163,000
Share grants, net of share grant amortization and forfeitures	2,544	$ 2	2,542			2,544
Balance, shares at Dec. 31, 2014		67,819,000
Balance at Dec. 31, 2014	822,229	$ 678	1,184,395	(365,518)	0	819,555	2,674
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to the controlling interests	89,740			89,740		89,740
Net loss attributable to noncontrolling interests	(553)
Unrealized gain on interest rate hedges	(550)				(550)	(550)
Net loss attributable to noncontrolling interests and deconsolidation of noncontrolling interest	(1,316)						(1,316)
Contributions from noncontrolling interest	5						5
Dividends	(82,003)			(82,003)		(82,003)
Stock issued during period (in shares)		184,000
Equity offerings, net of issuance costs	5,215	$ 2	5,213			5,215
Share grants, net of share grant amortization and forfeitures (in shares)		188,000
Share grants, net of share grant amortization and forfeitures	3,692	$ 2	3,690			3,692
Balance, shares at Dec. 31, 2015		68,191,000
Balance at Dec. 31, 2015	837,012	$ 682	1,193,298	(357,781)	(550)	835,649	1,363
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative Effect of New Accounting Principle in Period of Adoption	(35)			(35)		(35)
Net income attributable to the controlling interests	119,339			119,339		119,339
Net loss attributable to noncontrolling interests	(51)						(51)
Unrealized gain on interest rate hedges	8,161				8,161	8,161
Distributions to noncontrolling interests	(196)						(196)
Dividends	(87,570)			(87,570)		(87,570)
Stock issued during period (in shares)		6,223,000
Equity offerings, net of issuance costs	172,936	$ 62	172,874			172,936
Shares issued under Dividend Reinvestment Program (in shares)		23,000
Shares issued under Dividend Reinvestment Program	700	$ 700	700			700
Share grants, net of share grant amortization and forfeitures (in shares)		169,000
Share grants, net of share grant amortization and forfeitures	1,766	$ 2	1,764			1,766
Balance, shares at Dec. 31, 2016		74,606,000
Balance at Dec. 31, 2016	$ 1,052,062	$ 746	$ 1,368,636	$ (326,047)	$ 7,611	$ 1,050,946	$ 1,116

Consolidated Statements Of Cash

Consolidated Statements Of Cash Flows $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Cash flows from operating activities
Net income	$ 119,288	$ 89,187	$ 111,601
Adjustments to reconcile net income to net cash provided by operating activities:
Gain on sale of real estate	(101,704)	(91,107)	(106,555)
Depreciation and amortization, including amounts in discontinued operations	108,406	108,935	96,011
Provision for losses on accounts receivable	1,706	1,368	1,402
Deferred tax benefit	(698)	0	0
Casualty (gain) and real estate impairment loss, net	(676)	5,909	0
Share-based compensation expense	3,491	5,112	4,995
Amortization of debt premiums, discounts and related financing costs	3,187	3,486	3,588
Loss on extinguishment of debt, net	0	119	0
Changes in other assets	(13,507)	(10,388)	(23,306)
Changes in other liabilities	(2,562)	(3,195)	(4,619)
Net cash provided by operating activities	116,931	109,426	83,117
Cash flows from investing activities
Real estate acquisitions, net	(227,413)	(151,682)	(194,536)
Capital improvements to real estate	(57,094)	(41,507)	(57,810)
Development in progress	(22,572)	(31,203)	(43,264)
Net cash received from sale of real estate	243,624	137,014	190,864
Cash released from (held in) replacement reserve escrows	4,860	(3,511)	(1,417)
Insurance proceeds	883	0	0
Non-real estate capital improvements	(920)	(2,129)	(1,719)
Net cash used in investing activities	(58,632)	(93,018)	(107,882)
Cash flows from financing activities
Line of credit borrowings, net	15,000	55,000	50,000
Principal payments – mortgage notes payable	(270,061)	(4,512)	(3,954)
Borrowing under construction loan	0	4,558	20,393
Notes payable repayments	0	(150,000)	(100,000)
Proceeds from dividend reinvestment program	700	0	0
Proceeds from term loan	100,000	150,000	0
Payment of financing costs	(1,590)	(5,095)	(742)
Dividends paid	(85,648)	(61,510)	(80,277)
Contributions from noncontrolling interests	0	5	9
Distributions to noncontrolling interests	(196)	0	(3,454)
Net proceeds from equity offerings	172,936	5,215	30,690
Payment of tax withholdings for restricted share awards	(1,960)	(2,071)	(2,416)
Net cash used in financing activities	(70,819)	(8,410)	(89,751)
Net (decrease) increase in cash and cash equivalents	(12,520)	7,998	(114,516)
Cash and cash equivalents at beginning of year	23,825	15,827	130,343
Cash and cash equivalents at end of year	11,305	23,825	15,827
Supplemental disclosure of cash flow information:
Cash paid for interest, net of capitalized interest expense	51,054	57,179	58,023
Cash paid for income taxes	65	261	156
Change in accrued capital improvements and development costs	(3,788)	(4,229)	(4,154)
Dividends payable	22,414	20,434	0
Mortgage notes payable assumed in connection with the acquisition of real estate	$ 0	$ 0	$ 100,861

Statement Of Comprehensive Inco

Statement Of Comprehensive Income Statement Of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 119,288	$ 89,187	$ 111,601
Other comprehensive income (loss):	8,161	(550)	0
Unrealized gain (loss) on interest rate hedges	127,449	88,637	111,601
Less: Net loss attributable to noncontrolling interests in subsidiaries	(51)	(553)	(38)
Comprehensive income attributable to the controlling interests	$ 127,500	$ 89,190	$ 111,639

Nature Of Business

Nature Of Business	12 Months Ended
	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature Of Business	NATURE OF BUSINESS Washington Real Estate Investment Trust (“Washington REIT”), a Maryland real estate investment trust, is a self-administered equity real estate investment trust, successor to a trust organized in 1960. Our business consists of the ownership and operation of income-producing real estate properties in the greater Washington Metro region. We own a diversified portfolio of office buildings, multifamily buildings and retail centers. Federal Income Taxes We believe that we qualify as a REIT under Sections 856-860 of the Internal Revenue Code and intend to continue to qualify as such. To maintain our status as a REIT, we are, among other things, required to distribute 90% of our REIT taxable income (which is, generally, our ordinary taxable income, with certain modifications), excluding any net capital gains and any deductions for dividends paid to our shareholders on an annual basis. When selling a property, we generally have the option of (a) reinvesting the sales proceeds of property sold, in a way that allows us to defer recognition of some or all taxable gain realized on the sale, (b) distributing gains to the shareholders with no tax to us or (c) treating net long-term capital gains as having been distributed to our shareholders, paying the tax on the gain deemed distributed and allocating the tax paid as a credit to our shareholders. During the three years ended December 31, 2016 , we sold our interests in the following properties (in thousands): Disposition Date Property Type Gain on Sale May 26, 2016 Dulles Station II (1) Office $ 527 June 27, 2016 Maryland Office Portfolio Transaction I (2) Office 23,585 September 22, 2016 Maryland Office Portfolio Transaction II (3) Office 77,592 Total 2016 $ 101,704 March 20, 2015 Country Club Towers Multifamily $ 30,277 September 9, 2015 1225 First Street (4) Multifamily — October 21, 2015 Munson Hill Towers Multifamily 51,395 December 14, 2015 Montgomery Village Center Retail 7,981 Total 2015 $ 89,653 January 21, 2014 Medical Office Portfolio Transactions III & IV (5) Medical Office $ 105,985 May 2, 2014 5740 Columbia Road Retail 570 Total 2014 $ 106,555 (1) Land held for future development and an interest in a parking garage. (2) Maryland Office Portfolio Transaction I consists of 6110 Executive Boulevard, 600 Jefferson Plaza, Wayne Plaza and West Gude Drive. (3) Maryland Office Portfolio Transaction II consists of 51 Monroe Street and One Central Plaza. (4) Interest in land held for future development. (5) Medical Office Portfolio Transactions III & IV consist of Woodburn Medical Park I and II and Prosperity Medical Center I, II and III. The taxable gains for Dulles Station II and the properties included in Maryland Office Portfolio Transaction I were distributed to shareholders through the quarterly dividends. The properties included in Maryland Office Portfolio Transaction II were identified for a reverse deferred exchange under Section 1031 of the Internal Revenue Code. We acquired the replacement property, Riverside Apartments, during the second quarter of 2016 (see note 3, under "Acquisition"). We reinvested a portion of the Medical Office Portfolio Transactions III and IV, Country Club Towers, Munson Hill Towers and Montgomery Village Center sales proceeds in replacement properties through deferred tax exchanges. Generally, and subject to our ongoing qualification as a REIT, no provisions for income taxes are necessary except for taxes on undistributed taxable income and taxes on the income generated by our taxable REIT subsidiaries (“TRSs”). Our TRSs are subject to corporate federal and state income tax on their taxable income at regular statutory rates, or as calculated under the alternative minimum tax, as appropriate. During the second quarter of 2016, we recognized an income tax benefit of $0.7 million from a reduction of the valuation allowance for a deferred tax asset at one of our taxable REIT subsidiaries. As of December 31, 2016 , our TRSs had deferred tax assets of $0.5 million , net of a valuation allowance of $2.9 million . The valuation allowance for deferred tax assets had a net decrease of $2.8 million during 2016. Our TRSs had no net deferred tax assets as of December 31, 2015. As of December 31, 2016 and 2015, our TRSs had deferred tax liabilities of $0.4 million and $0.7 million , respectively. These deferred tax liabilities are primarily related to temporary differences in the timing of the recognition of revenue, amortization and depreciation. The following is a breakdown of the taxable percentage of our dividends for these years ended December 31, 2016, 2015 and 2014 (unaudited): 2016 2015 2014 Ordinary income 66 % 78 % 40 % Return of capital 33 % 22 % 52 % Qualified dividends — % — % — % Unrecaptured Section 1250 gain 1 % — % 8 % Capital gain — % — % — %

Accounting Policies

Accounting Policies	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES AND BASIS OF PRESENTATION Principles of Consolidation and Basis of Presentation The accompanying audited consolidated financial statements include the consolidated accounts of Washington REIT, our majority-owned subsidiaries and entities in which Washington REIT has a controlling interest, including where Washington REIT has been determined to be a primary beneficiary of a variable interest entity (“VIE”). See note 3 for additional information on the properties for which there is a noncontrolling interest. All intercompany balances and transactions have been eliminated in consolidation. We have prepared the accompanying audited consolidated financial statements pursuant to the rules and regulations of the Securities and Exchange Commission. Use of Estimates in the Financial Statements The preparation of financial statements in conformity with Generally Accepted Accounting Principles ("GAAP") requires management to make certain estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Recent Accounting Pronouncements In January 2017, the Financial Accounting Standards Board (the "FASB") issued Accounting Standards Update No. 2017-01, Business Combinations (Topic 805) - Clarifying the Definition of a Business , which adds guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions of assets or businesses. Under the new guidance, a set of transferred assets and activities is not a business when substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or group of similar identifiable assets. If a set of transferred assets and activities does not meet this threshold, then an entity must evaluate whether the set meets the requirement that a business include, at a minimum, an input and a substantive process that together significantly contribute to the ability to create outputs. The new standard is effective for public entities for fiscal years beginning after December 15, 2017 and for interim periods therein. Early adoption of the standard is allowed for transactions that have not been reported in financial statements issued prior to the new standards issuance date. Prior to the new guidance, we accounted for acquisitions of operating properties as business combinations, but generally expect that future acquisitions of operating properties will be accounted for as asset acquisitions under the new guidance. Acquisition costs are capitalized in asset acquisitions but expensed in business combinations. Identifiable assets, liabilities assumed and any noncontrolling interests are recognized and measured as of the acquisition date at fair value in a business combination, but are measured by allocating the cost of the acquisition on a relative fair value basis in an asset acquisition. In November 2016, the FASB issued Accounting Standards Update No. 2016-18, Statement of Cash Flows (Topic 230) - Restricted Cash , which requires that restricted cash and cash equivalents be included with cash and cash equivalents when reconciling beginning-of-period and end-of-period total amounts shown on the consolidated statements of cash flows. The new standard is effective for public entities for fiscal years beginning after December 15, 2017 and for interim periods therein, with early adoption permitted. We are currently evaluating the impact the new standard may have on Washington REIT’s consolidated financial statements. In August 2016, the FASB issued Accounting Standards Update No. 2016-15, Classification of Certain Cash Receipts and Cash Payments , which provides specific guidance on how cash receipts and payments should be presented and classified in the statement of cash flows for eight specific issues. The new standard is effective for public entities for fiscal years beginning after December 15, 2017 and for interim periods therein, with early adoption permitted. We are currently evaluating the impact the new standard may have on Washington REIT’s consolidated financial statements. In June 2016, the FASB issued Accounting Standards Update No. 2016-13, Measurement of Credit Losses on Financial Instruments , which requires financial assets measured at an amortized cost basis, including trade receivables, to be presented at the net amount expected to be collected. The new standard is effective for public entities for fiscal years beginning after December 15, 2019 and for interim periods therein with adoption one year earlier permitted. We are currently evaluating the impact the new standard may have on Washington REIT’s consolidated financial statements. In March 2016, the FASB issued Accounting Standards Update No. 2016-09, Improvements to Employee Share-Based Payment Accounting ("ASU 2016-09"), which amends existing accounting standards for employee share-based payments, including by allowing an employer to make a policy election to account for forfeitures as they occur or to continue to provide for an estimate as currently required. ASU 2016-09 also allows an employer to withhold shares in a net settlement in an amount that does not exceed the maximum statutory tax rate in the employees' tax jurisdiction without causing liability classification, and clarifies that all cash payments made to taxing authorities on the employees' behalf for withheld shares should be presented as financing activities on the consolidated statements of cash flows. ASU 2016-09 is effective for public entities for fiscal years beginning after December 15, 2016 and for interim periods therein with early adoption permitted. We adopted ASU 2016-09 as of December 31, 2016 and elected to account for forfeitures as they occur. In accordance with ASU 2016-09, we used the modified retrospective transition method for this election, resulting in a charge to retained earnings of less than $0.1 million . Regarding the cash payments made to taxing authorities on the employees' behalf for withheld shares, we had previously presented such payments as operating activities on our consolidated statements of cash flows, and have applied this change retrospectively. The impact of the implementation of ASU 2016-09 on our consolidated statements of cash flows is as follows (in thousands): Year Ended December 31, 2016 2015 2014 Net cash provided by operating activities (prior to adoption of ASU 2016-09) $ 114,971 $ 107,355 $ 80,701 Reclassification of cash payments for withheld shares 1,960 2,071 2,416 Net cash provided by operating activities (after adoption of ASU 2016-09) $ 116,931 $ 109,426 $ 83,117 Net cash used in financing activities (prior to adoption of ASU 2016-09) $ (68,859 ) $ (6,339 ) $ (87,335 ) Reclassification of cash payments for withheld shares (1,960 ) (2,071 ) (2,416 ) Net cash used in financing activities (after adoption of ASU 2016-09) $ (70,819 ) $ (8,410 ) $ (89,751 ) In February 2016, the FASB issued Accounting Standards Update No. 2016-05, Derivatives and Hedging (Topic 815) , which clarifies that a change in the counterparty to a derivative instrument that has been designated as the hedging instrument under Topic 815, in and of itself, does not require dedesignation of that hedging relationship provided that all other hedging criteria continue to be met. The new standard is effective for public entities for fiscal years beginning after December 15, 2016 and for interim periods therein with early adoption permitted. We do not expect the new standard to have a material impact on Washington REIT’s consolidated financial statements. In February 2016, the FASB issued Accounting Standards Update No. 2016-02, Leases (Topic 842) ("ASU 2016-02") , which amends existing accounting standards for lease accounting, including by requiring lessees to recognize most leases on the balance sheet and making certain changes to lessor accounting. The new standard is effective for public entities for fiscal years beginning after December 15, 2018 and for interim periods therein with early adoption permitted. Upon adoption, for leases in which we are the lessor, the lease contract will be separated into lease and non-lease components in accordance with the provisions outlined within ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) ("ASU 2014-09"). The lease component of the contract will be recognized on a straight-line basis in accordance with ASU 2016-02, while the non-lease component will be recognized under the provisions of ASU 2014-09. For lease contracts with a duration of more than one year in which we are the lessee, the present value of future lease payments will be recognized on our balance sheet as a right-of-use asset and a corresponding lease liability. Also, only direct leasing costs may be capitalized under the new standard, while current accounting standards allow for the capitalization of indirect leasing costs. We are currently evaluating the impact ASU 2016-02 may have on Washington REIT’s consolidated financial statements. In February 2015, the FASB issued Accounting Standards Update No. 2015-02, Consolidation (Topic 810) , which changes the analysis an entity must perform to determine whether it should consolidate certain types of legal entities. Specifically, the new standard i) modifies the evaluation of whether limited partnerships and similar legal entities are variable interest entities ("VIEs") or voting interest entities, ii) eliminates the presumption that a general partner should consolidate a limited partnership and iii) affects the consolidation analysis of reporting entities that are involved with VIEs, particularly those that have fee arrangements and related party relationships. The new standard is effective for public entities for fiscal years beginning after December 15, 2015 and for interim periods therein. We adopted the new standard on January 1, 2016, and the provisions of the new standard did not have any impact on the consolidation of our legal entities. In August 2014, the FASB issued ASU No. 2014-15, Presentation of Financial Statements - Going Concern (Subtopic 205-40) , which provides guidance on management's responsibility to evaluate whether there is substantial doubt about an entity's ability to continue as a going concern and to provide related footnote disclosures. Under the new standard, if conditions or events raise substantial doubt about an entity's ability to continue as a going concern, and substantial doubt is not alleviated after consideration of management's plans, an entity should include a statement in the footnotes indicating that there is substantial doubt about the entity's ability to continue as a going concern. The new standard is effective for fiscal years ending after December 15, 2016 and for annual and interim periods thereafter. We adopted the new standard during the fourth quarter of 2016 and the adoption did not require any disclosures about our ability to continue as a going concern. In June 2014, the FASB issued ASU 2014-09, which creates a single source of revenue guidance. The new standard provides accounting guidance for all revenue arising from contracts with customers and affects all entities that enter into contracts to provide goods or services to their customers (unless the contracts are in the scope of other GAAP requirements, such as the leasing literature). The guidance also provides a model for the measurement and recognition of gains and losses on the sale of certain nonfinancial assets, such as property and equipment, including real estate. The new standard is effective for public entities for fiscal years beginning after December 15, 2017 and for interim periods therein. Early adoption is permitted for public entities beginning after December 15, 2016. We intend to adopt the new standard using the modified retrospective method. Upon adoption of ASU 2016-02, Leases (Topic 842), the majority of our revenue will be subject to the allocation provisions outlined within the revenue standard. We are currently evaluating the specific implementation requirements for allocating the consideration within our contracts in accordance with ASU No. 2014-09. We do not expect the new standard to have a material impact on the measurement and recognition of gains and losses on the sale of properties. Revenue Recognition We lease multifamily properties under operating leases with terms of generally one year or less. We lease commercial properties (our office and retail segments) under operating leases with an average term of seven years. Substantially all commercial leases contain fixed escalations or, in some instances, changes based on the Consumer Price Index, which occur at specified times during the term of the lease. We recognize rental income and rental abatements from our multifamily and commercial leases when earned on a straight-line basis over the lease term. Recognition of rental income commences when control of the leased space has been given to the tenant. We recognize sales of real estate at closing only when sufficient down payments have been obtained, possession and other attributes of ownership have been transferred to the buyer and we have no significant continuing involvement. We recognize cost reimbursement income from pass-through expenses on an accrual basis over the periods in which the expenses were incurred. Pass-through expenses are comprised of real estate taxes, operating expenses and common area maintenance costs which are reimbursed by tenants in accordance with specific allowable costs per tenant lease agreements. Parking revenues are derived from leases, monthly parking agreements and transient parking. We recognize parking revenues from leases on a straight-line basis over the lease term and other parking revenues as earned. Accounts Receivable and Allowance for Doubtful Accounts Accounts receivable primarily represents amounts accrued and unpaid from tenants in accordance with the terms of the respective leases, subject to our revenue recognition policy. We review receivables monthly and establish reserves when, in the opinion of management, collection of the receivable is doubtful. We establish reserves for tenants whose rent payment histories or financial conditions cast doubt upon the tenants’ abilities to perform under their lease obligations. When we determine the collection of a receivable to be doubtful in the same quarter that we established the receivable, we recognize the allowance for that receivable as an offset to real estate revenues. When we determine a receivable that was initially established in a prior quarter to be doubtful, we recognize the allowance as an operating expense in Real estate expenses in the consolidated statements of income. In addition to rents due currently, accounts receivable include amounts representing minimal rental income accrued on a straight-line basis to be paid by tenants over the remaining term of their respective leases. Our accounts receivable balances include $2.4 million and $3.9 million of notes receivable as of December 31, 2016 and 2015 , respectively. Debt Issuance Costs We amortize external debt issuance costs using the effective interest rate method or the straight-line method which approximates the effective interest rate method, over the estimated life of the related debt. We record debt issuance costs related to notes and mortgage notes, net of amortization, on our consolidated balance sheets as an offset to their related debt. We record debt issuance costs related to revolving lines of credit on our consolidated balance sheets with Prepaid expenses and other assets, regardless of whether a balance on the line of credit is outstanding. We record the amortization of all debt issuance costs as interest expense. Deferred Leasing Costs We capitalize and amortize costs associated with the successful negotiation of leases, both external commissions and internal direct costs, on a straight-line basis over the terms of the respective leases. We record the amortization of deferred leasing costs in Depreciation and amortization on the consolidated statements of income. If an applicable lease terminates prior to the expiration of its initial lease term, we write off the carrying amount of the costs to amortization expense. We capitalize and amortize against revenue leasing incentives associated with the successful negotiation of leases on a straight-line basis over the terms of the respective leases. We record the amortization of deferred leasing incentives as a reduction of revenue. If an applicable lease terminates prior to the expiration of its initial lease term, we write off the carrying amount of the costs as a reduction of revenue. Real Estate and Depreciation We depreciate buildings on a straight-line basis over estimated useful lives ranging from 28 to 50 years. We capitalize all capital improvements associated with replacements, improvements or major repairs to real property that extend its useful life and depreciate them using the straight-line method over their estimated useful lives ranging from 3 to 30 years. We also capitalize costs incurred in connection with our development projects, including capitalizing interest incurred on borrowing obligations and other internal costs during periods in which qualifying expenditures have been made and activities necessary to get the development projects ready for their intended use are in progress. Capitalization of these costs begin when the activities and related expenditures commence and cease when the project is substantially complete and ready for its intended use, at which time the project is placed in service and depreciation commences. In addition, we capitalize tenant leasehold improvements when certain criteria are met, including when we supervise construction and will own the improvements. We depreciate all tenant improvements over the shorter of the useful life of the improvements or the term of the related tenant lease. Real estate depreciation expense from continuing operations was $84.1 million , $80.7 million , $71.4 million during the years ended December 31, 2016 , 2015 and 2014 , respectively. We charge maintenance and repair costs that do not extend an asset’s useful life to expense as incurred. Interest expense and interest capitalized to real estate assets related to development and major renovation activities for the three years ended December 31, 2016 were as follows (in thousands): Year Ended December 31, 2016 2015 2014 Total interest incurred $ 53,794 $ 60,204 $ 61,927 Capitalized interest (668 ) (658 ) (2,142 ) Interest expense, net of capitalized interest $ 53,126 $ 59,546 $ 59,785 We recognize impairment losses on long-lived assets used in operations, development assets or land held for future development, if indicators of impairment are present and the net undiscounted cash flows estimated to be generated by those assets are less than the assets' carrying amount and estimated undiscounted cash flows associated with future development expenditures. If such carrying amount is in excess of the estimated undiscounted cash flows from the operation and disposal of the property, we would recognize an impairment loss equivalent to an amount required to adjust the carrying amount to its estimated fair value, calculated in accordance with current GAAP fair value provisions. Assets held for sale are recorded at the lower of cost or fair value less costs to sell. We record acquired or assumed assets, including physical assets and in-place leases, and liabilities, based on their fair values. We determine the fair values of acquired buildings on an “as-if-vacant” basis considering a variety of factors, including the replacement cost of the property, estimated rental and absorption rates, estimated future cash flows and valuation assumptions consistent with current market conditions. We determine the fair value of land acquired based on comparisons to similar properties that have been recently marketed for sale or sold. The fair value of in-place leases consists of the following components – (a) the estimated cost to us to replace the leases, including foregone rents during the period of finding a new tenant and foregone recovery of tenant pass-throughs (referred to as “absorption cost”); (b) the estimated cost of tenant improvements, and other direct costs associated with obtaining a new tenant (referred to as “tenant origination cost”); (c) estimated leasing commissions associated with obtaining a new tenant (referred to as “leasing commissions”); (d) the above/at/below market cash flow of the leases, determined by comparing the projected cash flows of the leases in place, including consideration of renewal options, to projected cash flows of comparable market-rate leases (referred to as “net lease intangible”); and (e) the value, if any, of customer relationships, determined based on our evaluation of the specific characteristics of each tenant’s lease and our overall relationship with the tenant (referred to as “customer relationship value”). We have attributed no value to customer relationships as of December 31, 2016 and 2015 . We discount the amounts used to calculate net lease intangibles using an interest rate which reflects the risks associated with the leases acquired. We classify tenant origination costs as Income producing property on our consolidated balance sheets and amortize the tenant origination costs as depreciation expense on a straight-line basis over the remaining life of the underlying leases. We classify leasing commissions and absorption costs as other assets and amortize leasing commissions and absorption costs as amortization expense on a straight-line basis over the remaining life of the underlying leases. We classify net lease intangible assets as other assets and amortize them on a straight-line basis as a decrease to real estate rental revenue over the remaining term of the underlying leases. We classify net lease intangible liabilities as other liabilities and amortize them on a straight-line basis as an increase to real estate rental revenue over the remaining term of the underlying leases. If any of the fair value of below market lease intangibles includes fair value associated with a renewal option, such amounts are not amortized until the renewal option is executed, else the related value is expensed at that time. Should a tenant terminate its lease, we accelerate the amortization of the unamortized portion of the tenant origination cost, leasing commissions, absorption costs and net lease intangible associated with that lease, over its new, shorter term. Balances, net of accumulated depreciation or amortization, as appropriate, of the components of the fair value of in-place leases at December 31, 2016 and 2015 were as follows (in thousands): December 31, 2016 2015 Gross Carrying Value Accumulated Amortization Net Gross Carrying Value Accumulated Amortization Net Tenant origination costs $ 54,352 $ 44,823 $ 9,529 $ 55,664 $ 41,138 $ 14,526 Leasing commissions/absorption costs 101,311 86,210 15,101 97,678 75,014 22,664 Net lease intangible assets 18,903 14,193 4,710 19,655 12,434 7,221 Net lease intangible liabilities 33,687 25,359 8,328 34,027 23,444 10,583 Below-market ground lease intangible asset 12,080 1,714 10,366 12,080 1,524 10,556 Amortization of these combined components during the three years ended December 31, 2016 , 2015 and 2014 was as follows (in thousands): Year Ended December 31, 2016 2015 2014 Depreciation and amortization expense $ 17,655 $ 22,244 $ 19,854 Real estate rental revenue, net 410 538 456 $ 18,065 $ 22,782 $ 20,310 Amortization of these combined components over the next five years is projected to be as follows (in thousands): Depreciation and amortization expense Real estate rental revenue, net decrease (increase) Total 2017 $ 8,874 $ (148 ) $ 8,726 2018 6,096 (633 ) 5,463 2019 3,572 (525 ) 3,047 2020 2,357 (320 ) 2,037 2021 1,411 (313 ) 1,098 Discontinued Operations We classify properties as held for sale when they meet the necessary criteria, which include: (a) senior management commits to and actively embarks upon a plan to sell the assets, (b) the sale is expected to be completed within one year under terms usual and customary for such sales and (c) actions required to complete the plan indicate that it is unlikely that significant changes to the plan will be made or that the plan will be withdrawn. We generally consider that a property has met these criteria when a sale of the property has been approved by the board of trustees, or a committee with authorization from the board of trustees, there are no known significant contingencies related to the sale and management believes it is probable that the sale will be completed within one year. Depreciation on these properties is discontinued at the time they are classified as held for sale, but operating revenues, operating expenses and interest expense continue to be recognized until the date of sale. Under ASU No. 2014-08, Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity , which we adopted as of January 1, 2014, revenues and expenses of properties that are either sold or classified as held for sale are presented as discontinued operations for all periods presented in the consolidated statements of income if the dispositions represent a strategic shift that has (or will have) a major effect on our operations and financial results. Interest on debt that can be identified as specifically attributed to these properties is included in discontinued operations. If the dispositions do not represent a strategic shift that has (or will have) a major effect on our operations and financial results, then the revenues and expenses of the properties that are classified as sold or held for sale are presented as continuing operations in the consolidated statements of income for all periods presented. The provisions of ASU No. 2014-08 apply only to properties classified as held for sale or sold after our adoption date of January 1, 2014. Segments We evaluate performance based upon net operating income from the combined properties in each segment. Our reportable operating segments are consolidations of similar properties. GAAP requires that segment disclosures present the measure(s) used by the chief operating decision maker for purposes of assessing segments’ performance. Net operating income is a key measurement of our segment profit and loss. Net operating income is defined as segment real estate rental revenue less segment real estate expenses. Cash and Cash Equivalents Cash and cash equivalents include cash and commercial paper with original maturities of 90 days or less. We maintain cash deposits with financial institutions that at times exceed applicable insurance limits. We reduce this risk by maintaining such deposits with high quality financial institutions that management believes are credit-worthy. Restricted Cash Restricted cash includes funds escrowed for tenant security deposits, real estate tax, insurance and mortgage escrows and escrow deposits required by lenders on certain of our properties to be used for future building renovations or tenant improvements. Earnings Per Common Share We determine “Basic earnings per share” using the two-class method as our unvested restricted share awards and units have non-forfeitable rights to dividends, and are therefore considered participating securities. We compute basic earnings per share by dividing net income attributable to the controlling interest less the allocation of undistributed earnings to unvested restricted share awards and units by the weighted-average number of common shares outstanding for the period. We also determine “Diluted earnings per share” under the two-class method with respect to the unvested restricted share awards. We further evaluate any other potentially dilutive securities at the end of the period and adjust the basic earnings per share calculation for the impact of those securities that are dilutive. Our dilutive earnings per share calculation includes the dilutive impact of employee stock options based on the treasury stock method and our performance share units under the contingently issuable method. Stock Based Compensation We currently maintain equity based compensation plans for trustees, officers and employees. We recognize compensation expense for service-based share awards ratably over the period from the service inception date through the vesting period based on the fair market value of the shares on the date of grant. If an award's service inception date precedes the grant date, we initially measure compensation expense for awards with performance conditions at fair value at the service inception date based on probability of payout, and we remeasure compensation expense at subsequent reporting dates until all of the award’s key terms and conditions are known and the grant date is established. We amortize awards with performance conditions using the graded expense method. We measure compensation expense for awards with market conditions based on the grant date fair value, as determined using a Monte Carlo simulation, and we amortize the expense ratably over the requisite service period, regardless of whether the market conditions are achieved and the awards ultimately vest. Compensation expense for the trustee grants, which fully vest immediately, is fully recognized upon issuance based upon the fair market value of the shares on the date of grant. Accounting for Uncertainty in Income Taxes We can recognize a tax benefit only if it is “more likely than not” that a particular tax position will be sustained upon examination or audit. To the extent that the “more likely than not” standard has been satisfied, the benefit associated with a tax position is measured as the largest amount that is greater than 50% likely of being recognized upon settlement. As of December 31, 2016 and 2015, we did not have any unrecognized tax benefits. We do not believe that there will be any material changes to our uncertain tax positions over the next twelve months. We are subject to federal income tax as well as income tax of the states of Maryland and Virginia, and the District of Columbia. However, as a REIT, we generally are not subject to income tax on our taxable income to the extent it is distributed as dividends to our shareholders. Tax returns filed for 2012 through 2016 tax years are subject to examination by taxing authorities. We classify interest and penalties related to uncertain tax positions, if any, in our financial statements as a component of general and administrative expense. Derivatives We borrow funds at a combination of fixed and variable rates. Borrowings under our revolving credit facility and term loans bear interest at variable rates. Our interest rate risk management objectives are to minimize interest rate fluctuation on long-term indebtedness and limit the impact of interest rate changes on earnings and cash flows. To achieve these objectives, from time to time, we may enter into interest rate hedge contracts such as collars, swaps, caps and treasury lock agreements in order to mitigate our interest rate risk with respect to various debt instruments. We generally do not hold or issue these derivative contracts for trading or speculative purposes. The interest rate swaps we enter into are recorded at fair value on a recurring basis. We assess effectiveness of our cash flow hedges both at inception and on an ongoing basis. The effective portion of changes in fair value of the interest rate swaps associated with our cash flow hedges is recorded in accumulated other comprehensive income (loss). Our cash flow hedges become ineffective if critical terms of the hedging instrument and the debt instrument such as notional amounts, settlement dates, reset dates, calculation period and LIBOR do not perfectly match. In addition, we evaluate the default risk of the counterparty by monitoring the creditworthiness of the counterparty. When ineffectiveness of a cash flow hedge exists, the ineffective portion of changes in fair value of the interest rate swaps associated with our cash flow hedges is recognized in earnings in the period affected. Reclassifications In prior years, we elected to present our real estate expenses on the consolidated statements of income disaggregated into the following categories: utilities, real estate taxes,

Real Estate Investments

Real Estate Investments	12 Months Ended
	Dec. 31, 2016
Real Estate [Abstract]
Real Estate Investment	REAL ESTATE As of December 31, 2016 and 2015 , our real estate investment portfolio, at cost, consists of properties as follows (in thousands): December 31, 2016 2015 Office $ 1,349,378 $ 1,554,334 Multifamily 885,084 641,424 Retail 450,941 442,039 $ 2,685,403 $ 2,637,797 Our results of operations are dependent on the overall economic health of our markets, tenants and the specific segments in which we own properties. These segments include office, retail and multifamily. All segments are affected by external economic factors, such as inflation, consumer confidence and unemployment rates, as well as changing tenant and consumer requirements. As of December 31, 2016 , one property, Riverside Apartments, accounted for more than 10% of total assets. No single property or tenant accounted for more than 10% of the real estate rental revenue. We have properties under development/redevelopment and held for current or future development as of December 31, 2016 and 2015. In the office segment, we had a redevelopment project to renovate Silverline Center, an office property in Tysons, Virginia. We completed major construction activities on this project during the second quarter of 2015, and placed into service substantially completed portions of the project at the time totaling $25.9 million , with the remaining components placed into service as of March 31, 2016. We also currently have a redevelopment project at the Army Navy Building, an office property in Washington, DC, to upgrade its common areas and add significant amenities in order to make the property more competitive within its sub-market. As of December 31, 2016, we had invested $2.2 million in the redevelopment. In the multifamily segment, we have Trove, a multifamily development adjacent to The Wellington, and own land held for future multifamily development adjacent to Riverside Apartments. As of December 31, 2016 , we had invested $19.0 million and $16.4 million , including the costs of acquired land, in Trove and the development adjacent to Riverside Apartments, respectively. In the retail segment, we currently have a redevelopment project to add rentable space at Spring Valley Shopping Center. As of December 31, 2016, we had invested $1.1 million in the redevelopment. The cost of our real estate portfolio under development or held for future development as of December 31, 2016 and 2015 is as follows (in thousands): December 31, 2016 2015 Office $ 2,640 $ 18,711 Multifamily 36,013 16,307 Retail 1,579 1,076 $ 40,232 $ 36,094 Acquisitions Our current strategy is to recycle legacy assets that lack the income growth potential we seek and to invest in high-quality assets with compelling value-add returns through redevelopment opportunities in our existing portfolio and acquisitions that meet our stringent investment criteria. We focus on properties inside the Washington metro region’s Beltway, near major transportation nodes and in areas with strong employment drivers and superior growth demographics. Properties and land for development acquired during the three years ended December 31, 2016 were as follows: Acquisition Date Property Type # of units (unaudited) Rentable Square Feet (unaudited) Contract Purchase Price (in thousands) May 20, 2016 Riverside Apartments Multifamily 1,222 N/A $ 244,750 July 1, 2015 The Wellington Multifamily 711 N/A $ 167,000 February 21, 2014 Yale West Multifamily 216 N/A $ 73,000 March 26, 2014 The Army Navy Building Office N/A 108,000 79,000 May 1, 2014 1775 Eye Street, NW Office N/A 185,000 104,500 October 1, 2014 Spring Valley Retail Center Retail N/A 75,000 40,500 Total 2014 216 368,000 $ 297,000 The results of operations from acquired operating properties are included in the consolidated statements of income as of their acquisition dates. The revenue and earnings of our acquisitions during their year of acquisition for the three years ended December 31, 2016 are as follows (in thousands): Year Ended December 31, 2016 2015 2014 Real estate rental revenue $ 13,112 $ 6,797 $ 16,260 Net loss (1,688 ) (2,748 ) (3,168 ) As discussed in note 2 , we record the acquired physical assets (land, building and tenant improvements), in-place leases (absorption, tenant origination costs, leasing commissions, and net lease intangible assets/liabilities), and any other liabilities at their fair values. We have recorded the total purchase price of the above acquisitions as follows (in thousands): 2016 2015 2014 Land $ 38,924 $ 30,548 $ 104,403 Land held for development 15,968 15,000 — Buildings 184,854 116,563 172,671 Tenant origination costs — — 9,377 Leasing commissions/absorption costs 4,992 4,889 16,474 Net lease intangible assets 22 — 7,331 Net lease intangible liabilities (10 ) — (8,323 ) Fair value of assumed mortgage — — (107,125 ) Furniture, fixtures & equipment — — 932 Total $ 244,750 $ 167,000 $ 195,740 The weighted remaining average life for 2016 acquisition components above, other than land and building, are 87 months for net lease intangible assets and 43 months for net lease intangible liabilities. The leasing commissions/absorption costs acquired in 2016 were substantially amortized as of December 31, 2016, as such costs were primarily related to assumed apartment leases. The net lease intangible assets and liabilities are associated with leases for retail space at Riverside Apartments. The difference in the total contract price of $244.8 million for the 2016 acquisition and cash paid for the acquisition per the consolidated statements of cash flows of $227.4 million is primarily due to acquisition of land for development of $16.0 million and credits received at settlement totaling $1.4 million . The difference in the total contract price of $167.0 million for the 2015 acquisition and cash paid for the acquisition per the consolidated statements of cash flows of $151.7 million is primarily due to acquisition of land for development of $15.0 million and credits received at settlement totaling $0.3 million . The difference in the total contract price of $297.0 million for the 2014 acquisitions and cash paid for the acquisitions per the consolidated statements of cash flows of $194.5 million is primarily due to the assumption of two mortgage notes secured by Yale West and The Army Navy Building for an aggregate carrying value of $100.9 million and the payment of a $3.6 million deposit for Yale West in 2013, partially offset by a credit to the seller for building renovations at 1775 Eye Street, NW for $1.9 million . The following unaudited pro-forma combined condensed statements of operations set forth the consolidated results of operations for the years ended December 31, 2016 and 2015 as if the above described acquisition in 2016 had occurred on January 1, 2015. The pro forma adjustments exclude acquisition costs directly related to the above-described acquisition. The unaudited pro-forma information does not purport to be indicative of the results that actually would have occurred if the acquisition had been in effect for the years ended December 31, 2016 and 2015 . The unaudited data presented is in thousands, except per share data. Year Ended December 31, 2016 2015 Real estate revenues $ 321,386 $ 327,605 Net income $ 127,439 $ 90,040 Diluted earnings per share $ 1.76 $ 1.31 Noncontrolling Interests in Subsidiaries In August 2007, we acquired a 0.8 acre parcel of land located at 4661 Kenmore Avenue, Alexandria, Virginia for future medical office development. The acquisition was funded by issuing operating partnership units in an operating partnership, which is a consolidated subsidiary of Washington REIT. This resulted in a noncontrolling ownership interest in this property based upon defined company operating partnership units at the date of purchase. In November 2013, 4661 Kenmore Avenue was sold as part of the Medical Office Portfolio (see "Properties Sold ") and in 2014, we distributed to the noncontrolling interest holder their share of the proceeds . Variable Interest Entities In November 2011, we executed a joint venture operating agreement with a real estate development company to develop a high-rise multifamily property at 1225 First Street in Alexandria, Virginia. Washington REIT and the real estate development company owned 95% and 5% of the joint venture, respectively. During the second quarter of 2015, we determined that we would not develop the property and began negotiations to sell our interest in the joint venture. We recognized a $5.9 million impairment charge for the second quarter of 2015 in order to reduce the carrying value of the property to its estimated fair value. We based this fair value on the contract sale price in the purchase and sale agreement. This fair valuation falls into Level 2 of the fair value hierarchy. During the third quarter of 2015, we sold our 95% interest in the joint venture for a contract sale price of $14.5 million and deconsolidated the entity, as this joint venture had previously been consolidated as Washington REIT was the primary beneficiary of the VIE. In June 2011, we executed a joint venture operating agreement with a real estate development company to develop The Maxwell, a mid-rise multifamily property in Arlington, Virginia. Major construction activities at The Maxwell ended during December 2014, and the building became available for occupancy during the first quarter of 2015. Washington REIT is the 90.0% owner of the joint venture. The real estate development company owns 10.0% of the joint venture and was responsible for the development and construction of the property. We have determined that The Maxwell joint venture is a VIE primarily based on the fact that the equity investment at risk is not sufficient to permit the entity to finance its activities without additional financial support. We also determined that Washington REIT was the primary beneficiary of the VIE due to the fact that Washington REIT was determined to have a controlling financial interest in the entity. As of December 31, 2015, $32.2 million was outstanding on The Maxwell's construction loan. In January 2016, Washington REIT exercised its right to purchase at par The Maxwell's construction loan from the original third-party lender. Upon the purchase, the loan became an intercompany payable from the consolidated VIE to Washington REIT that is eliminated in consolidation. We include joint venture land acquisitions and related capitalized development costs on our consolidated balance sheets in properties under development or held for future development until placed in service or sold. The Maxwell was placed into service during the fourth quarter of 2014 and first quarter of 2015. As of December 31, 2016 and 2015 , The Maxwell's assets were as follows (in thousands): December 31, 2016 2015 Land $ 12,851 $ 12,851 Income producing property 37,949 37,791 Accumulated depreciation and amortization (4,571 ) (2,347 ) Other assets 456 1,188 $ 46,685 $ 49,483 As of December 31, 2016 and 2015 , The Maxwell's liabilities were as follows (in thousands): December 31, 2016 2015 Mortgage notes payable, net $ 31,869 (1) $ 32,214 Accounts payable and other liabilities 186 256 Tenant security deposits 99 82 $ 32,154 $ 32,552 (1) The mortgage notes payable balance as of December 31, 2016 is eliminated in consolidation due to the purchase of the loan by Washington REIT in January 2016. Properties Sold We intend to hold our properties for investment with a view to long-term appreciation, to engage in the business of acquiring, developing and owning our properties, and to make occasional sales of the properties that no longer meet our long-term strategy or return objectives and where market conditions for sale are favorable. The proceeds from the sales may be reinvested into other properties, used to fund development operations or to support other corporate needs, or distributed to our shareholders. Depreciation on these properties is discontinued when classified as held for sale, but operating revenues, other operating expenses and interest continue to be recognized until the date of sale. There were no properties held for sale as of December 31, 2016 or 2015. During the second quarter of 2016, we sold Dulles Station, Phase II, which consists of land held for future development and an interest in a parking garage in Herndon, Virginia, for $12.1 million . Also during the second quarter of 2016, we executed two purchase and sale agreements with a single buyer for the sale of a portfolio of six office properties located in Maryland: 6110 Executive Boulevard, Wayne Plaza, 600 Jefferson Plaza, West Gude Drive, 51 Monroe Street and One Central Plaza (collectively, the "Maryland Office Portfolio") for an aggregate contract sales price of $240.0 million . We closed on the first sale transaction in June 2016 and closed on the second sale transaction in September 2016. During the second quarter of 2015, 15,000 square feet of land at Montrose Shopping Center, a retail property in Rockville, Maryland, was condemned as part of an eminent domain taking action. The taken land was at the periphery of the property and its taking did not impact the property's operations. We received $2.0 million as compensation for the taken land, and recognized a $1.4 million gain on sale of real estate during the second quarter of 2015. We sold our interests in the following properties during the three years ended December 31, 2016 : Disposition Date Property Segment # of units (unaudited) Rentable Contract Gain on Sale May 26, 2016 Dulles Station, Phase II (1) Office N/A N/A $ 12,100 $ 527 June 27, 2016 Maryland Office Portfolio Transaction I (2) Office N/A 692,000 111,500 23,585 September 22, 2016 Maryland Office Portfolio Transaction II (3) Office N/A 491,000 128,500 77,592 Total 2016 1,183,000 $ 252,100 $ 101,704 March 20, 2015 Country Club Towers Multifamily 227 N/A $ 37,800 $ 30,277 September 9, 2015 1225 First Street (4) Multifamily N/A N/A 14,500 — October 21, 2015 Munson Hill Towers Multifamily 279 N/A 57,050 51,395 December 14, 2015 Montgomery Village Center Retail N/A 197,000 27,750 7,981 Total 2015 506 197,000 $ 137,100 $ 89,653 January 21, 2014 Medical Office Portfolio Transactions III & IV (5) Medical Office N/A 427,000 $ 193,561 $ 105,985 May 2, 2014 5740 Columbia Road Retail N/A 3,000 1,600 570 Total 2014 N/A 430,000 $ 195,161 $ 106,555 (1) Land held for future development and an interest in a parking garage. (2) Maryland Office Portfolio Transaction I consists of 6110 Executive Boulevard, 600 Jefferson Plaza, Wayne Plaza and West Gude Drive. (3) Maryland Office Portfolio Transaction II consists of 51 Monroe Street and One Central Plaza. (4) Interest in land held for future development. (5) These properties are classified as discontinued operations. All other sold properties are classified as continuing operations. We do not have significant continuing involvement in the operations of the disposed properties. While the Maryland Office Portfolio, in the aggregate, constitutes an individually significant disposition, it does not qualify for presentation and disclosure as a discontinued operation as it does not represent a strategic shift in our operations. Real estate rental revenue and net income for the Maryland Office Portfolio for the three years ended December 31, 2016 are as follows: Year Ending December 31, 2016 2015 2014 Real estate rental revenue $ 20,266 $ 32,423 $ 31,811 Net income 9,376 9,848 9,352 In September 2013 , we entered into four separate purchase and sale agreements to effectuate the sale of our entire medical office segment (including land held for development at 4661 Kenmore Avenue) and two office buildings (Woodholme Center and 6565 Arlington Boulevard) for an aggregate purchase price of $500.8 million . The sale was structured as four transactions. Transactions I & II closed in November 2013 and Transactions III & IV in January 2014 . The impact of the sale of our medical office segment on revenues and net income is summarized as follows (in thousands, except per share data): Year Ending December 31, 2016 2015 2014 Real estate revenues $ — $ — $ 892 Net income — — 546 Basic and diluted net income per share — — 0.01 Income from properties classified as discontinued operations for the three years ended December 31, 2016 was as follows (in thousands): Year Ending December 31, 2016 2015 2014 Revenues $ — $ — $ 892 Property expenses — — (346 ) $ — $ — $ 546 Casualty Gains We recorded a net casualty gain of $0.7 million during the second quarter of 2016 associated with a fire at Bethesda Hill Towers that damaged four units, which is included in casualty (gain) and real estate impairment loss, net on our consolidated statements of income. The net casualty gain is comprised of $0.9 million in third-party insurance proceeds received by us, which were partially offset by casualty charges of $0.2 million to write off the net book value of the damaged units at Bethesda Hill Towers.

Mortgage Notes Payable

Mortgage Notes Payable	12 Months Ended
	Dec. 31, 2016
Notes Payable, Noncurrent [Abstract]
Mortgage Notes Payable	MORTGAGE NOTES PAYABLE As of December 31, 2016 and 2015 , we had outstanding mortgage notes payable, each collateralized by one or more buildings and related land from our portfolio, as follows (in thousands): December 31, Properties Assumption/Issuance Date (1) Effective Interest Rate (2) 2016 2015 Payoff Date/Maturity Date Army Navy Building (3) 3/26/2014 3.18 % $ 49,618 $ 50,750 2/1/2017 Yale West (4) 2/21/2014 3.75 % 47,078 47,502 1/31/2022 The Maxwell (5) 2/21/2013 2.27 % — 32,248 1/27/2016 John Marshall II (6) 9/15/2011 5.79 % — 51,011 2/8/2016 Olney Village Center 8/30/2011 4.94 % 14,851 16,503 10/1/2023 Kenmore Apartments 2/2/2009 5.37 % 32,938 33,637 3/1/2019 2445 M Street (7) 12/2/2008 7.25 % — 101,866 10/6/2016 3801 Connecticut Avenue, Walker House and Bethesda Hill (8) 5/29/2008 5.71 % — 81,029 6/1/2016 144,485 414,546 Premiums and discounts, net 4,354 4,175 Debt issuance costs, net (299 ) (669 ) $ 148,540 $ 418,052 (1) Each of these mortgages was assumed with the acquisition of the collateralized properties, except for the mortgage notes secured by 3801 Connecticut Avenue, Walker House, Bethesda Hill, Kenmore Apartments, and the construction loan secured by the development project at The Maxwell, which were originally executed by Washington REIT. We record mortgages assumed in an acquisition at fair value. (2) Yield on the assumption/issuance date, including the effects of any premiums, discounts or fair value adjustments on the notes. (3) The note was prepaid without penalty in February 2017. (4) The maturity date of the mortgage note is January 1, 2052, but can be prepaid, without penalty, beginning on January 31, 2022. (5) Interest rate on The Maxwell construction loan was variable, based on LIBOR plus 2.0% . Interest and principal was payable monthly starting March 2016 until the extended maturity date of February 20, 2017, upon which all unpaid principal and interest were payable in full. In January 2016, Washington REIT exercised its right to purchase the construction loan without penalty from the lender (see note 3, under "Variable Interest Entities"). (6) The note was prepaid without penalty in February 2016. (7) Interest only was payable monthly until the note was prepaid without penalty in October 2016. (8) Interest only was payable monthly until the note was repaid without penalty in June 2016. Except as noted above, principal and interest are payable monthly until the maturity date, upon which all unpaid principal and interest are payable in full. Total carrying amount of the above mortgaged properties was $280.4 million and $619.4 million at December 31, 2016 and 2015 , respectively. Scheduled principal payments subsequent to December 31, 2016 are as follows (in thousands): 2017 $ 52,571 2018 3,135 2019 33,909 2020 2,659 2021 2,829 Thereafter 49,382 $ 144,485 In February 2017, we prepaid without penalty the remaining $49.6 million of the mortgage note secured by the Army Navy Building using borrowings on our 2016 Term Loan.

Unsecured Lines Of Credit Payab

Unsecured Lines Of Credit Payable	12 Months Ended
	Dec. 31, 2016
Unsecured Debt [Abstract]
Unsecured Lines Of Credit Payable	UNSECURED LINES OF CREDIT PAYABLE During the second quarter of 2015, we terminated our $100.0 million unsecured line of credit maturing in June 2015 and our $400.0 million unsecured line of credit maturing in July 2016 , and executed a new $600.0 million unsecured credit agreement ("Revolving Credit Facility") that matures in June 2019 , unless extended pursuant to one or both of the two six -month extension options. The Revolving Credit Facility has an accordion feature that allows us to increase the facility to $1.0 billion , subject to the extent the lenders agree to provide additional revolving loan commitments or term loans. In September 2015, we entered into a $150.0 million unsecured term loan ("2015 Term Loan") by executing a portion of the accordion feature under the Revolving Credit Facility. The 2015 Term Loan has a 5.5 year term and currently has an interest rate of one month LIBOR plus 110 basis points, based on Washington REIT's current unsecured debt ratings. We entered into two interest rate swaps to effectively fix the interest rate at 2.7% (see note 7 ). The amount of the Revolving Credit Facility unused and available at December 31, 2016 was as follows (in thousands): Committed capacity $ 600,000 Borrowings outstanding (120,000 ) Unused and available $ 480,000 We executed borrowings and repayments on the Revolving Credit Facility during 2016 as follows (in thousands): Balance at December 31, 2015 $ 105,000 Borrowings 651,000 Repayments (636,000 ) Balance at December 31, 2016 $ 120,000 The Revolving Credit Facility bears interest at a rate of either one month LIBOR plus a margin ranging from 0.875% to 1.55% or the base rate plus a margin ranging from 0% to 0.55% (in each case depending upon Washington REIT’s credit rating). The base rate is the highest of the administrative agent's prime rate, the federal funds rate plus 0.5% and the one month LIBOR market index rate plus 1.0% . As of December 31, 2016 , the interest rate on the facility is one month LIBOR plus 1.0% and the one month LIBOR was 0.77% . All outstanding advances for the Revolving Credit Facility are due and payable upon maturity in June 2019 , unless extended pursuant to one or both of the two six-month extension options. Interest only payments are due and payable generally on a monthly basis. In addition, the Revolving Credit Facility requires the payment of a facility fee ranging from 0.125% to 0.30% (depending on Washington REIT’s credit rating) on the $600.0 million committed capacity, without regard to usage. As of December 31, 2016 , the facility fee is 0.20% . For the three years ended December 31, 2016 , we recognized interest expense (excluding facility fees) and facility fees as follows (in thousands): Year Ended December 31, 2016 2015 2014 Interest expense (excluding facility fees) $ 3,272 $ 2,266 $ 196 Facility fees 1,220 1,241 1,267 The Revolving Credit Facility contains certain financial and non-financial covenants, all of which we have met as of December 31, 2016 and 2015 . Included in these covenants are limits on our total indebtedness, secured and unsecured indebtedness and required debt service payments. Information related to revolving credit facilities for the three years ended December 31, 2016 as follows (in thousands, except percentage amounts): Year Ended December 31, 2016 2015 2014 Total revolving credit facilities at December 31 $ 600,000 $ 600,000 $ 500,000 Borrowings outstanding at December 31 120,000 105,000 50,000 Weighted average daily borrowings during the year 214,962 167,573 12,849 Maximum daily borrowings during the year 358,000 350,000 55,000 Weighted average interest rate during the year 1.52 % 1.35 % 1.53 % Weighted average interest rate on borrowings outstanding at December 31 1.64 % 1.36 % 1.37 % The covenants under our Revolving Credit Facility require us to insure our properties against loss or damage in amounts customarily maintained by similar businesses or as they may be required by applicable law. The covenants for the notes require us to keep all of our insurable properties insured against loss or damage at least equal to their then full insurable value. We have an insurance policy that has no terrorism exclusion, except for non-certified nuclear, chemical and biological acts of terrorism. Our financial condition and results of operations are subject to the risks associated with acts of terrorism and the potential for uninsured losses as the result of any such acts. Effective November 26, 2002, under this existing coverage, any losses caused by certified acts of terrorism would be partially reimbursed by the United States under a formula established by federal law. Under this formula, the United States pays 85% of covered terrorism losses exceeding the statutorily established deductible paid by the insurance provider, and insurers pay 10% until aggregate insured losses from all insurers reach $100 billion in a calendar year. If the aggregate amount of insured losses under this program exceeds $100 billion during the applicable period for all insured and insurers combined, then each insurance provider will not be liable for payment of any amount which exceeds the aggregate amount of $100 billion . On January 12, 2015, the Terrorism Risk Insurance Program Reauthorization Act of 2015 was signed into law and extended the program through December 31, 2020. NOTES PAYABLE Our unsecured notes outstanding as of December 31, 2016 were as follows (in thousands): Coupon/Stated Rate Effective Rate (1) Principal Amount Maturity Date (2) 10 Year Unsecured Notes 4.95 % 5.05 % $ 250,000 10/1/2020 2015 Term Loan 1 Month LIBOR + 110 basis points 2.72 % 150,000 3/15/2021 10 Year Unsecured Notes 3.95 % 4.02 % 300,000 10/15/2022 2016 Term Loan 1 Month LIBOR + 165 basis points 2.86 % 100,000 7/21/2023 30 Year Unsecured Notes 7.25 % 7.36 % 50,000 2/25/2028 Total principal 850,000 Premiums and discounts, net (1,971 ) Deferred issuance costs, net (4,945 ) Total $ 843,084 (1) For fixed rate notes, the effective rate represents the yield on issuance date, including the effects of discounts on the notes. For variable rate notes, the effective rate represents the rate as fixed by interest rate derivatives (see note 7 ). (2) No principal amounts are due prior to maturity. During the third quarter of 2016, we entered into a seven year, $150.0 million unsecured term loan ("2016 Term Loan") maturing on July 21, 2023 with a deferred draw period of up to six months commencing on July 22, 2016 . The 2016 Term Loan bears interest at a rate of either LIBOR plus a margin ranging from 1.50% to 2.45% or the base rate plus a margin ranging from 0.5% to 1.45% (in each case depending upon Washington REIT’s credit rating). The base rate is the highest of the administrative agent's prime rate, the federal funds rate plus 0.50% and the daily one-month LIBOR rate plus 1.0% . The 2016 Term Loan currently has an interest rate of one month LIBOR plus 165 basis points, based on Washington REIT's current unsecured debt ratings. We borrowed $100.0 million on the term loan in the fourth quarter of 2016, and borrowed the remaining $50.0 million subsequent to the end of 2016. We also entered into forward interest rate derivatives commencing on March 31, 2017 to effectively fix the interest rate on the 2016 Term Loan at 2.86% (see note 7 ). The required principal payments as of December 31, 2016 are as follows (in thousands): 2017 $ — 2018 — 2019 — 2020 250,000 2021 150,000 Thereafter 450,000 $ 850,000 Interest on these notes is payable semi-annually, except for the term loans, for which interest is payable monthly. These notes contain certain financial and non-financial covenants, all of which we have met as of December 31, 2016 . Included in these covenants is the requirement to maintain a minimum level of unencumbered assets, as well as limits on our total indebtedness, secured indebtedness and required debt service payments.

Notes Payable

Notes Payable	12 Months Ended
	Dec. 31, 2016
Notes Payable [Abstract]
Notes Payable	UNSECURED LINES OF CREDIT PAYABLE During the second quarter of 2015, we terminated our $100.0 million unsecured line of credit maturing in June 2015 and our $400.0 million unsecured line of credit maturing in July 2016 , and executed a new $600.0 million unsecured credit agreement ("Revolving Credit Facility") that matures in June 2019 , unless extended pursuant to one or both of the two six -month extension options. The Revolving Credit Facility has an accordion feature that allows us to increase the facility to $1.0 billion , subject to the extent the lenders agree to provide additional revolving loan commitments or term loans. In September 2015, we entered into a $150.0 million unsecured term loan ("2015 Term Loan") by executing a portion of the accordion feature under the Revolving Credit Facility. The 2015 Term Loan has a 5.5 year term and currently has an interest rate of one month LIBOR plus 110 basis points, based on Washington REIT's current unsecured debt ratings. We entered into two interest rate swaps to effectively fix the interest rate at 2.7% (see note 7 ). The amount of the Revolving Credit Facility unused and available at December 31, 2016 was as follows (in thousands): Committed capacity $ 600,000 Borrowings outstanding (120,000 ) Unused and available $ 480,000 We executed borrowings and repayments on the Revolving Credit Facility during 2016 as follows (in thousands): Balance at December 31, 2015 $ 105,000 Borrowings 651,000 Repayments (636,000 ) Balance at December 31, 2016 $ 120,000 The Revolving Credit Facility bears interest at a rate of either one month LIBOR plus a margin ranging from 0.875% to 1.55% or the base rate plus a margin ranging from 0% to 0.55% (in each case depending upon Washington REIT’s credit rating). The base rate is the highest of the administrative agent's prime rate, the federal funds rate plus 0.5% and the one month LIBOR market index rate plus 1.0% . As of December 31, 2016 , the interest rate on the facility is one month LIBOR plus 1.0% and the one month LIBOR was 0.77% . All outstanding advances for the Revolving Credit Facility are due and payable upon maturity in June 2019 , unless extended pursuant to one or both of the two six-month extension options. Interest only payments are due and payable generally on a monthly basis. In addition, the Revolving Credit Facility requires the payment of a facility fee ranging from 0.125% to 0.30% (depending on Washington REIT’s credit rating) on the $600.0 million committed capacity, without regard to usage. As of December 31, 2016 , the facility fee is 0.20% . For the three years ended December 31, 2016 , we recognized interest expense (excluding facility fees) and facility fees as follows (in thousands): Year Ended December 31, 2016 2015 2014 Interest expense (excluding facility fees) $ 3,272 $ 2,266 $ 196 Facility fees 1,220 1,241 1,267 The Revolving Credit Facility contains certain financial and non-financial covenants, all of which we have met as of December 31, 2016 and 2015 . Included in these covenants are limits on our total indebtedness, secured and unsecured indebtedness and required debt service payments. Information related to revolving credit facilities for the three years ended December 31, 2016 as follows (in thousands, except percentage amounts): Year Ended December 31, 2016 2015 2014 Total revolving credit facilities at December 31 $ 600,000 $ 600,000 $ 500,000 Borrowings outstanding at December 31 120,000 105,000 50,000 Weighted average daily borrowings during the year 214,962 167,573 12,849 Maximum daily borrowings during the year 358,000 350,000 55,000 Weighted average interest rate during the year 1.52 % 1.35 % 1.53 % Weighted average interest rate on borrowings outstanding at December 31 1.64 % 1.36 % 1.37 % The covenants under our Revolving Credit Facility require us to insure our properties against loss or damage in amounts customarily maintained by similar businesses or as they may be required by applicable law. The covenants for the notes require us to keep all of our insurable properties insured against loss or damage at least equal to their then full insurable value. We have an insurance policy that has no terrorism exclusion, except for non-certified nuclear, chemical and biological acts of terrorism. Our financial condition and results of operations are subject to the risks associated with acts of terrorism and the potential for uninsured losses as the result of any such acts. Effective November 26, 2002, under this existing coverage, any losses caused by certified acts of terrorism would be partially reimbursed by the United States under a formula established by federal law. Under this formula, the United States pays 85% of covered terrorism losses exceeding the statutorily established deductible paid by the insurance provider, and insurers pay 10% until aggregate insured losses from all insurers reach $100 billion in a calendar year. If the aggregate amount of insured losses under this program exceeds $100 billion during the applicable period for all insured and insurers combined, then each insurance provider will not be liable for payment of any amount which exceeds the aggregate amount of $100 billion . On January 12, 2015, the Terrorism Risk Insurance Program Reauthorization Act of 2015 was signed into law and extended the program through December 31, 2020. NOTES PAYABLE Our unsecured notes outstanding as of December 31, 2016 were as follows (in thousands): Coupon/Stated Rate Effective Rate (1) Principal Amount Maturity Date (2) 10 Year Unsecured Notes 4.95 % 5.05 % $ 250,000 10/1/2020 2015 Term Loan 1 Month LIBOR + 110 basis points 2.72 % 150,000 3/15/2021 10 Year Unsecured Notes 3.95 % 4.02 % 300,000 10/15/2022 2016 Term Loan 1 Month LIBOR + 165 basis points 2.86 % 100,000 7/21/2023 30 Year Unsecured Notes 7.25 % 7.36 % 50,000 2/25/2028 Total principal 850,000 Premiums and discounts, net (1,971 ) Deferred issuance costs, net (4,945 ) Total $ 843,084 (1) For fixed rate notes, the effective rate represents the yield on issuance date, including the effects of discounts on the notes. For variable rate notes, the effective rate represents the rate as fixed by interest rate derivatives (see note 7 ). (2) No principal amounts are due prior to maturity. During the third quarter of 2016, we entered into a seven year, $150.0 million unsecured term loan ("2016 Term Loan") maturing on July 21, 2023 with a deferred draw period of up to six months commencing on July 22, 2016 . The 2016 Term Loan bears interest at a rate of either LIBOR plus a margin ranging from 1.50% to 2.45% or the base rate plus a margin ranging from 0.5% to 1.45% (in each case depending upon Washington REIT’s credit rating). The base rate is the highest of the administrative agent's prime rate, the federal funds rate plus 0.50% and the daily one-month LIBOR rate plus 1.0% . The 2016 Term Loan currently has an interest rate of one month LIBOR plus 165 basis points, based on Washington REIT's current unsecured debt ratings. We borrowed $100.0 million on the term loan in the fourth quarter of 2016, and borrowed the remaining $50.0 million subsequent to the end of 2016. We also entered into forward interest rate derivatives commencing on March 31, 2017 to effectively fix the interest rate on the 2016 Term Loan at 2.86% (see note 7 ). The required principal payments as of December 31, 2016 are as follows (in thousands): 2017 $ — 2018 — 2019 — 2020 250,000 2021 150,000 Thereafter 450,000 $ 850,000 Interest on these notes is payable semi-annually, except for the term loans, for which interest is payable monthly. These notes contain certain financial and non-financial covenants, all of which we have met as of December 31, 2016 . Included in these covenants is the requirement to maintain a minimum level of unencumbered assets, as well as limits on our total indebtedness, secured indebtedness and required debt service payments.

Derivative Instruments

Derivative Instruments	12 Months Ended
	Dec. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments	DERIVATIVE INSTRUMENTS On September 15, 2015 , we entered into two interest rate swap arrangements with a total notional amount of $150.0 million to swap the floating interest rate under the 2015 Term Loan (see note 6 ) to an all-in fixed interest rate of 2.7% starting on October 15, 2015 and extending until the maturity of the 2015 Term Loan on March 15, 2021 . On July 22, 2016 , we entered into two forward interest rate swap arrangements with a total notional amount of $150.0 million to swap the floating interest rate under the 2016 Term Loan (see note 6) to an all-in fixed interest rate of 2.86% , starting on March 31, 2017 and extending until the maturity of the 2016 Term Loan on July 21, 2023 . The interest rate swaps qualify as cash flow hedges and are recorded at fair value in accordance with GAAP, based on discounted cash flow methodologies and observable inputs. We record the effective portion of changes in fair value of the cash flow hedges in other comprehensive income (loss). The resulting unrealized loss on the effective portions of the cash flow hedges was the only activity in other comprehensive income (loss) during the periods presented in our consolidated financial statements. We assess the effectiveness of our cash flow hedges both at inception and on an ongoing basis. The cash flow hedges were effective for 2016 and 2015 and hedge ineffectiveness did not impact earnings in 2016 and 2015 . The fair values of the interest rate swaps as of December 31, 2016 and 2015 , are as follows (in thousands): Aggregate Notional Amount Effective Date Fair Value Asset Derivatives Liability Derivatives December 31, December 31, Derivative Instrument Maturity Date 2016 2015 2016 2015 Interest rate swaps $ 150,000 October 15, 2015 March 15, 2021 $ 417 $ — $ — $ 550 Interest rate swaps 150,000 March 31, 2017 July 21, 2023 7,194 N/A — N/A $ 300,000 $ 7,611 $ — $ — $ 550 We record interest rate swaps on our consolidated balance sheets with prepaid expenses and other assets when in a net asset position, and with accounts payable and other liabilities when in a net liability position. The interest rate swaps have been effective since inception. The gains or losses on the effective swaps are recognized in other comprehensive income (loss), as follows (in thousands): Year Ending December 31, 2016 2015 2014 Unrealized gain (loss) on interest rate hedges $ 8,161 $ (550 ) $ — Amounts reported in accumulated other comprehensive income (loss) related to derivatives will be reclassified to interest expense as interest payments are made on our variable-rate debt. During the next twelve months, we estimate that $1.2 million will be reclassified as a decrease to interest expense. We have agreements with each of our derivative counterparties that contain a provision whereby we could be declared in default on our derivative obligations if repayment of the underlying indebtedness is accelerated by the lender due to our default on the indebtedness. As of December 31, 2016 , the fair values of derivatives were in a net asset position of $7.6 million , including accrued interest but excluding any adjustment for nonperformance risk. As of December 31, 2016 , we have not posted any collateral related to these agreements. Derivative instruments expose us to credit risk in the event of non-performance by the counterparty under the terms of the interest rate hedge agreement. We believe that we minimize our credit risk on these transactions by dealing with major, creditworthy financial institutions. We monitor the credit ratings of counterparties and our exposure to any single entity, thus minimizing our credit risk concentration.

Fair Value Disclosures

Fair Value Disclosures	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Fair Value Disclosures	FAIR VALUE DISCLOSURES Assets and Liabilities Measured at Fair Value For assets and liabilities measured at fair value on a recurring basis, quantitative disclosures about the fair value measurements are required to be disclosed separately for each major category of assets and liabilities, as follows: Level 1: Quoted prices in active markets for identical assets Level 2: Significant other observable inputs Level 3: Significant unobservable inputs The only assets or liabilities we had at December 31, 2016 and 2015 that are recorded at fair value on a recurring basis are the assets held in the Supplemental Executive Retirement Plan ("SERP"), which primarily consists of investments in mutual funds, and the interest rate swaps (see note 7 ). We base the valuations related to the SERP on assumptions derived from significant other observable inputs and accordingly these valuations fall into Level 2 in the fair value hierarchy. The valuation of the interest rate swaps is determined using widely accepted valuation techniques, including discounted cash flow analysis on the expected cash flows of each interest rate swap. This analysis reflects the contractual terms of the interest rate swaps, including the period to maturity, and uses observable market-based inputs, including interest rate curves and implied volatilities. The fair values of interest rate swaps are determined using the market standard methodology of netting the discounted future fixed cash payments (or receipts) and the discounted expected variable cash receipts (or payments). The variable cash payments (or receipts) are based on an expectation of future interest rates (forward curves) derived from observable market interest rate curves. To comply with the provisions of ASC 820, we incorporate credit valuation adjustments in the fair value measurements to appropriately reflect both our own nonperformance risk and the respective counterparty’s nonperformance risk. These credit valuation adjustments were concluded to not be significant inputs for the fair value calculations for the periods presented. In adjusting the fair value of our derivative contracts for the effect of nonperformance risk, we have considered the impact of netting and any applicable credit enhancements, such as the posting of collateral, thresholds, mutual puts and guarantees. The valuation of interest rate swaps fall into Level 2 in the fair value hierarchy. The fair values of these assets and liabilities at December 31, 2016 and 2015 were as follows (in thousands): December 31, 2016 December 31, 2015 Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets: SERP $ 1,407 $ — $ 1,407 $ — $ 1,408 $ — $ 1,408 $ — Derivatives 7,611 — 7,611 — — — — — Liabilities: Derivatives — — — — 550 — 550 — Financial Assets and Liabilities Not Measured at Fair Value The following disclosures of estimated fair value were determined by management using available market information and established valuation methodologies, including discounted cash flow. Many of these estimates involve significant judgment. The estimated fair value disclosed may not necessarily be indicative of the amounts we could realize on disposition of the financial instruments. The use of different market assumptions or estimation methodologies could have an effect on the estimated fair value amounts. In addition, fair value estimates are made at a point in time and thus, estimates of fair value subsequent to December 31, 2016 may differ significantly from the amounts presented. Below is a summary of significant methodologies used in estimating fair values and a schedule of fair values at December 31, 2016 . Cash and Cash Equivalents and Restricted Cash Cash and cash equivalents and restricted cash include cash and commercial paper with original maturities of less than 90 days , which are valued at the carrying value, which approximates fair value due to the short maturity of these instruments (Level 1 inputs). Notes Receivable We acquired a note receivable ("2445 M Street note") in 2008 with the purchase of 2445 M Street. We estimate the fair value of the 2445 M Street note based on a discounted cash flow methodology using market discount rates (Level 3 inputs). Debt Mortgage notes payable consist of instruments in which certain of our real estate assets are used for collateral. We estimate the fair value of the mortgage notes payable by discounting the contractual cash flows at a rate equal to the relevant treasury rates (with respect to the timing of each cash flow) plus credit spreads estimated through independent comparisons to real estate assets or loans with similar characteristics. Lines of credit payable consist of bank facilities which we use for various purposes including working capital, acquisition funding and capital improvements. The lines of credit advances and term loans with floating interest rates are priced at a specified rate plus a spread. We estimate the market value based on a comparison of the spreads of the advances to market given the adjustable base rate. We estimate the fair value of the notes payable by discounting the contractual cash flows at a rate equal to the relevant treasury rates (with respect to the timing of each cash flow) plus credit spreads derived using the relevant securities’ market prices. We classify these fair value measurements as Level 3 as we use significant unobservable inputs and management judgment due to the absence of quoted market prices. As of December 31, 2016 and 2015 , the carrying values and estimated fair values of our financial instruments were as follows (in thousands): December 31, 2016 2015 Carrying Value Fair Value Carrying Value Fair Value Cash and cash equivalents $ 11,305 $ 11,305 $ 23,825 $ 23,825 Restricted cash 6,317 6,317 13,383 13,383 2445 M Street note receivable 2,089 2,173 3,849 4,275 Mortgage notes payable 148,540 149,997 418,052 426,693 Lines of credit payable 120,000 120,000 105,000 105,000 Notes payable 843,084 873,516 743,181 753,816

Stock Based Compensation

Stock Based Compensation	12 Months Ended
	Dec. 31, 2016
Share-based Compensation [Abstract]
Stock Based Compensation	STOCK BASED COMPENSATION Washington REIT maintains short-term and long-term incentive plans that allow for stock-based awards to officers and non-officer employees. Stock based awards are provided to officers and non-officer employees, as well as trustees, under the Washington Real Estate Investment Trust 2016 Omnibus Incentive Plan which allows for awards in the form of restricted shares, restricted share units, options, and other awards up to an aggregate of 2,400,000 shares over the ten year period in which the plan will be in effect. Restricted share units are converted into shares of our stock upon full vesting through the issuance of new shares. There were no options issued or outstanding as of December 31, 2016 and 2015 . Prior to the adoption of the 2016 Omnibus Incentive Plan, stock based awards to officers, non-officer employees and trustees were issued under the Washington Real Estate Investment Trust 2007 Omnibus Long-Term Incentive Plan which allowed for awards in the form of restricted shares, restricted share units, options and other awards up to an aggregate of 2,000,000 shares while the plan was in effect. Short-Term Incentive Plan ("STIP") Under the STIP, executive officers earn awards, payable 50% in cash and 50% in restricted shares, based on a percentage of salary and an achievement rating subject to the discretion of the Compensation Committee of the board of trustees in consideration of various performance conditions and other subjective factors during a one -year performance period. With respect to the 50% of the STIP award payable in restricted shares, the restricted shares will vest over a three -year period commencing on the January 1 following the end of the one -year performance period. The grant date for the 50% of the STIP award payable in restricted shares is the date on which the Compensation Committee approves the STIP awards. We recognize compensation expense on this 50% when the grant date occurs at the end of the one -year period through the three -year vesting period. Bonuses payable under the short-term incentive plans for non-executive officers and non-officers are payable 100% in cash. Long-Term Incentive Plan ("LTIP") Under the LTIP, executive officers earn awards payable, 75% in unrestricted shares and 25% in restricted shares, based on a percentage of salary and the achievement of certain market conditions. LTIP performance is evaluated based 50% on absolute total shareholder return (“TSR”) and 50% on relative TSR over a three -year evaluation period with a new three -year period initiating under the existing plan each year. The officers' total award opportunities under the LTIP stated as a percentage of base salary ranges from 80% to 150% at target level. The unrestricted shares vest immediately at the end of the three -year performance period, and the restricted shares vest over a one -year period commencing on the January 1 following the end of the three -year performance period. In addition, during the transition period from the prior LTIP in 2014, the board of trustees awarded similar transition awards with defined performance periods of one and two years and modified vesting to account for the transition. We recognize compensation expense ratably (over three years for the 75% unrestricted shares and over four years for the 25% restricted shares) based on the grant date fair value, as determined using a Monte Carlo simulation, and regardless of whether the market conditions are achieved and the awards ultimately vest. We use a binomial model which employs the Monte Carlo method as of the grant date to determine the fair value of the officer LTIP awards. The market condition performance measurement is based on total shareholder return on both an absolute basis ( 50% weighting) and relative to a defined population of 15 peer companies ( 50% weighting). The model evaluates the awards for changing total shareholder return over the term of the vesting, on an absolute basis and relative to the peer companies, and uses random simulations that are based on past stock characteristics as well as dividend growth and other factors for Washington REIT and each of the peer companies. The assumptions used to value the officer LTIP awards were as follows: 2016 Awards 2015 Awards 2014 Awards Expected volatility (1) 18.2 % 17.2 - 17.5% 23.2 % Risk-free interest rate (2) 1.32 % 1.0 - 1.1% 0.8 % Expected term (3) 3 and 4 years 3 and 4 years 3 and 4 years Share price at grant date $27.06 $27.66 - $27.76 $24.08 (1) Expected volatility based upon historical volatility of our daily closing share price. (2) Risk-free interest rate based on U.S. treasury constant maturity bonds on the measurement date with a maturity equal to the market condition performance period. (3) Expected term based on the market condition performance period. The calculated grant date fair value as a percentage of base salary for the officers for the three-year performance period that commenced in 2016 ranged from approximately 38% to 66% for the 50% of the LTIP based on relative TSR and from 17% to 30% for the 50% of the LTIP based on absolute TSR. The calculated grant date fair value as a percentage of base salary for the officers for the three-year performance period that commenced in 2015 ranged from approximately 40% to 69% for the 50% of the LTIP based on relative TSR and from 13% to 29% for the 50% of the LTIP based on absolute TSR. The calculated grant date fair value as a percentage of base salary for the officers for the three-year performance period that commenced in 2014 ranged from approximately 42% to 67% for the 50% of the LTIP based on relative TSR and from 24% to 38% for the 50% of the LTIP based on absolute TSR. For the one -year transition awards, the calculated grant date fair value as a percentage of base salary for the officers for the one -year performance period that commenced in 2014 ranged from approximately 11% to 20% for the 50% of the LTIP based on relative TSR and from 10% to 20% for the 50% of the LTIP based on absolute TSR. For the two -year transition awards, the calculated grant date fair value as a percentage of base salary for the officers for the two -year performance period that commenced in 2014 ranged from approximately 23% to 43% for the 50% of the LTIP based on relative TSR and from 16% to 30% for the 50% of the LTIP based on absolute TSR. Our non-executive officers and other employees earn restricted share unit awards under a new long-term incentive plan for non-executive officers and staff, which became effective on January 1, 2016, based upon various percentages of their salaries and annual performance calculations. The restricted share unit awards vest ratably over three years from December 15 preceding the grant date based upon continued employment. For awards made through 2016, the service inception date precedes the grant date. For these awards, we initially measured compensation expense for awards with performance conditions at fair value at the service inception date based on probability of payout, and we remeasured compensation expense at subsequent reporting dates until all of the award's key terms and conditions are known and the grant date is established. We recognized compensation expense for these awards according to a graded vesting schedule over the four -year requisite service period. During 2016, we amended the LTIP for other officers and other employees. Among the changes to the LTIP was the inclusion of strategic goals with subjective performance criteria. As a result of these changes, the service inception date is the same as the grant date for awards made under the amended LTIP. We recognize compensation expense for these awards according to a graded vesting schedule over the three-year requisite service period. Restricted share awards made to retirement-eligible employees fully vest on the grant date. Employees are considered retirement-eligible when they are both over the age of 55 and have been employed by Washington REIT for at least 20 years, or over the age of 65. We fully recognize compensation expense for such awards as of the grant date. Trustee Awards We award share based compensation to our trustees in the form of restricted shares which vest immediately and are restricted from sale for the period of the trustees' service. The value of share-based compensation for each trustee was $100,000 , $100,000 and $55,000 for the each of three years ended December 31, 2016 , respectively. Total Compensation Expense Total compensation expense recognized in the consolidated financial statements for each of the three years ended December 31, 2016 for all share based awards was $3.5 million , $5.1 million and $5.0 million , respectively. The stock-based compensation expense for 2016 and 2015 is net of $0.1 million and $0.6 million , respectively, of capitalized stock-based compensation expense. Capitalized stock-based compensation expense in 2014 was not material. Restricted Share Awards with Performance and Service Conditions The activity for the three years ended December 31, 2016 related to our restricted share awards, excluding those subject to market conditions, was as follows: Shares Wtd Avg Grant Fair Value Unvested at December 31, 2013 129,815 $ 27.06 Granted 210,817 23.93 Vested during year (236,498 ) 25.06 Forfeited (10,467 ) 25.80 Unvested at December 31, 2014 93,667 25.22 Granted 251,642 27.80 Vested during year (212,856 ) 27.18 Forfeited (26,309 ) 26.77 Unvested at December 31, 2015 106,144 27.71 Granted 251,694 26.01 Vested during year (211,771 ) 29.21 Forfeited (38,368 ) 26.14 Unvested at December 31, 2016 107,699 26.47 The total fair value of share grants vested for each of the three years ended December 31, 2016 was $6.2 million , $5.8 million and $6.1 million , respectively. As of December 31, 2016 , the total compensation cost related to non-vested share awards not yet recognized was $1.9 million , which we expect to recognize over a weighted average period of 20 months . Restricted and Unrestricted Shares with Market Conditions Stock based awards with market conditions under the LTIP were granted in 2016, 2015 and 2014 with fair market values, as determined using a Monte Carlo simulation, as follows (in thousands): Grant Date Fair Value 2016 Awards 2015 Awards 2014 Awards Restricted Unrestricted Restricted Unrestricted Restricted Unrestricted Relative TSR $ 182 $ 546 $ 191 $ 634 $ 458 $ 1,376 Absolute TSR 82 246 76 254 327 921 The unamortized value of these awards with market conditions as of December 31, 2016 was as follows (in thousands): 2016 Awards 2015 Awards 2014 Awards Restricted Unrestricted Restricted Unrestricted Restricted Unrestricted Relative TSR $ 117 $ 314 $ 83 $ 165 $ 33 $ — Absolute TSR 53 142 33 66 19 —

Other Benefit Plans

Other Benefit Plans	12 Months Ended
	Dec. 31, 2016
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]
Other Benefit Plans	OTHER BENEFIT PLANS We have a Retirement Savings Plan (the “401(k) Plan”), which permits all eligible employees to defer a portion of their compensation in accordance with the Internal Revenue Code. Under the 401(k) Plan, we may make discretionary contributions on behalf of eligible employees. For each of the three years ended December 31, 2016 , we made contributions to the 401(k) plan of $0.4 million , $0.5 million and $0.4 million , respectively. We have adopted non-qualified deferred compensation plans for the officers and members of the board of trustees. The plans allow for a deferral of a percentage of annual cash compensation and trustee fees. The plans are unfunded and payments are to be made out of the general assets of Washington REIT. The deferred compensation liability was $0.9 million and $1.7 million at December 31, 2016 and 2015 , respectively. In November 2005, the board of trustees approved the establishment of a Supplemental Executive Retirement Plan (“SERP”) for the benefit of officers. This is a defined contribution plan under which, upon a participant's termination of employment from Washington REIT for any reason other than discharge for cause, the participant will be entitled to receive a benefit equal to the participant's accrued benefit times the participant's vested interest. We account for this plan in accordance with ASC 710-10 and ASC 320-10, whereby the investments are reported at fair value, and unrealized holding gains and losses are included in earnings. At December 31, 2016 and 2015 , the accrued benefit liability was $1.3 million and $1.4 million , respectively. For each of the three years ended December 31, 2016 , we recognized current service cost of $0.2 million , $0.3 million and $0.3 million , respectively.

Earnings Per Common Share

Earnings Per Common Share	12 Months Ended
	Dec. 31, 2016
Earnings Per Share [Abstract]
Earnings per Common Share	EARNINGS PER COMMON SHARE We determine “Basic earnings per share” using the two-class method as our unvested restricted share awards and units have non-forfeitable rights to dividends, and are therefore considered participating securities. We compute basic earnings per share by dividing net income attributable to the controlling interest less the allocation of undistributed earnings to unvested restricted share awards and units by the weighted-average number of common shares outstanding for the period. We also determine “Diluted earnings per share” as the more dilutive of the two-class method or the treasury stock method with respect to the unvested restricted share awards. We further evaluate any other potentially dilutive securities at the end of the period and adjust the basic earnings per share calculation for the impact of those securities that are dilutive. Our dilutive earnings per share calculation includes the dilutive impact of employee stock options (prior to their expiration at December 31, 2014) based on the treasury stock method and our share based awards with performance conditions prior to the grant date and all market condition awards under the contingently issuable method. The computation of basic and diluted earnings per share for the three years ended December 31, 2016 was as follows (in thousands; except per share data): Year Ended December 31, 2016 2015 2014 Numerator: Income from continuing operations $ 119,288 $ 89,187 $ 5,070 Net loss attributable to noncontrolling interests 51 553 — Allocation of undistributed earnings to unvested restricted share awards and units to continuing operations (310 ) (269 ) 5 Adjusted income from continuing operations attributable to the controlling interests 119,029 89,471 5,075 Income from discontinued operations, including gain on sale of real estate, net of taxes — — 106,531 Net loss attributable to noncontrolling interests — — 38 Allocation of undistributed earnings to unvested restricted share awards and units to discontinued operations — — (322 ) Adjusted income from discontinued operations attributable to the controlling interests — — 106,247 Adjusted net income attributable to the controlling interests $ 119,029 $ 89,471 $ 111,322 Denominator: Weighted average shares outstanding – basic 72,163 68,177 66,795 Effect of dilutive securities: Employee stock options and restricted share awards 176 133 42 Weighted average shares outstanding – diluted 72,339 68,310 66,837 Earnings per common share, basic: Continuing operations $ 1.65 $ 1.31 $ 0.08 Discontinued operations — — 1.59 $ 1.65 $ 1.31 $ 1.67 Earnings per common share, diluted: Continuing operations $ 1.65 $ 1.31 $ 0.08 Discontinued operations — — 1.59 $ 1.65 $ 1.31 $ 1.67 Dividends declared per common share $ 1.20 $ 1.20 $ 1.20

Rentals Under Operating Leases

Rentals Under Operating Leases	12 Months Ended
	Dec. 31, 2016
Rentals Under Operating Leases [Abstract]
Rentals Under Operating Leases	RENTALS UNDER OPERATING LEASES As of December 31, 2016 , non-cancelable commercial operating leases provide for minimum rental income were as follows (in thousands): 2017 $ 172,783 2018 153,100 2019 141,158 2020 126,193 2021 100,887 Thereafter 327,421 $ 1,021,542 Apartment leases are not included as the terms are generally for one year. Most of these commercial leases increase in future years based on agreed-upon percentages or in some instances, changes in the Consumer Price Index. Real estate tax, operating expense and common area maintenance reimbursement income from continuing operations for the three years ended December 31, 2016 was $35.2 million , $34.6 million and $31.6 million , respectively.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES Development Commitments At December 31, 2016 , we had no committed contracts outstanding with third parties in connection with our development and redevelopment projects. Litigation We are involved from time to time in various legal proceedings, lawsuits, examinations by various tax authorities and claims that have arisen in the ordinary course of business. Management believes that the resolution of any such current matters will not have a material adverse effect on our financial condition or results of operations.

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2016
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Segment Information	SEGMENT INFORMATION We evaluate real estate performance and allocate resources by property type and have three reportable segments: office, multifamily, and retail. Office properties provide office space for various types of businesses and professions. Multifamily properties provide rental housing for individuals and families throughout the Washington metro region. Retail properties are typically grocery store anchored neighborhood centers that include other small shop tenants or regional power centers with several junior box tenants. Real estate rental revenue as a percentage of the total for each of the reportable operating segments in continuing operations for the three years ended December 31, 2016 was as follows: Year Ended December 31, 2016 2015 2014 Office 53 % 57 % 57 % Multifamily 27 % 22 % 22 % Retail 20 % 21 % 21 % The percentage of total income producing real estate assets, at cost, for each of the reportable operating segments in continuing operations as of December 31, 2016 and 2015 was as follows: December 31, 2016 2015 Office 50 % 59 % Multifamily 33 % 24 % Retail 17 % 17 % The accounting policies of each of the segments are the same as those described in note 2. We evaluate performance based upon net operating income from the combined properties in each segment. Our reportable operating segments are consolidations of similar properties. GAAP requires that segment disclosures present the measure(s) used by the chief operating decision maker for purposes of assessing segments’ performance. Net operating income is a key measurement of our segment profit and loss. Net operating income is defined as segment real estate rental revenue less segment real estate expenses. The following tables present revenues, net operating income, capital expenditures and total assets for the three years ended December 31, 2016 from these segments, and reconciles net operating income of reportable segments to net income attributable to the controlling interests as reported (in thousands): Year Ended December 31, 2016 Office Retail Multifamily Corporate Consolidated Real estate rental revenue $ 165,934 $ 61,566 $ 85,764 $ — $ 313,264 Real estate expenses 64,405 15,860 34,748 — 115,013 Net operating income $ 101,529 $ 45,706 $ 51,016 $ — $ 198,251 Depreciation and amortization (108,406 ) General and administrative (19,545 ) Casualty gain and real estate impairment (loss), net 676 Acquisition costs (1,178 ) Interest expense (53,126 ) Other income 297 Gain on sale of real estate 101,704 Income tax benefit 615 Net income 119,288 Less: Net loss attributable to noncontrolling interests 51 Net income attributable to the controlling interests $ 119,339 Capital expenditures $ 30,337 $ 8,821 $ 17,936 $ 920 $ 58,014 Total assets $ 1,104,589 $ 352,056 $ 762,695 $ 34,279 $ 2,253,619 Year Ended December 31, 2015 Office Retail Multifamily Corporate and Other Consolidated Real estate rental revenue $ 174,378 $ 63,507 $ 68,542 $ — $ 306,427 Real estate expenses 67,228 15,606 29,400 — 112,234 Net operating income $ 107,150 $ 47,901 $ 39,142 $ — $ 194,193 Depreciation and amortization (108,935 ) General and administrative (20,123 ) Real estate impairment (5,909 ) Acquisition costs (2,056 ) Interest expense (59,546 ) Other income 709 Gain on sale of real estate 91,107 Income tax expense (134 ) Loss on extinguishment of debt (119 ) Net income 89,187 Less: Net income attributable to noncontrolling interests 553 Net income attributable to the controlling interests $ 89,740 Capital expenditures $ 29,745 $ 3,897 $ 7,865 $ 2,129 $ 43,636 Total assets $ 1,265,570 $ 354,123 $ 529,773 $ 41,702 $ 2,191,168 Year Ended December 31, 2014 Office Retail Multifamily Corporate Consolidated Real estate rental revenue $ 166,116 $ 60,263 $ 62,258 $ — $ 288,637 Real estate expenses 63,903 14,022 25,770 — 103,695 Net operating income $ 102,213 $ 46,241 $ 36,488 $ — $ 184,942 Depreciation and amortization (96,011 ) General and administrative (19,644 ) Acquisition costs (5,710 ) Interest expense (59,785 ) Other income 825 Gain on sale of real estate 570 Income tax expense (117 ) Discontinued operations: Income from properties sold or held for sale 546 Gain on sale of real estate 105,985 Net income 111,601 Less: Net income attributable to noncontrolling interests 38 Net income attributable to the controlling interests $ 111,639 Capital expenditures $ 43,128 $ 5,496 $ 9,186 $ 1,719 $ 59,529 Total assets $ 1,283,950 $ 385,074 $ 408,114 $ 31,179 $ 2,108,317

Selected Quarterly Financial Da

Selected Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Selected Quarterly Financial Data (Unaudited)	SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED) Unaudited financial data by quarter in each of the years ended December 31, 2016 and 2015 were as follows (in thousands, except for per share data): Quarter (1), (2), (3) First Second Third Fourth 2016 Real estate rental revenue $ 77,137 $ 79,405 $ 79,770 $ 76,952 Net income $ 2,379 $ 31,821 $ 79,662 $ 5,426 Net income attributable to the controlling interests $ 2,384 $ 31,836 $ 79,674 $ 5,445 Net income per share Basic $ 0.03 $ 0.44 $ 1.07 $ 0.07 Diluted $ 0.03 $ 0.44 $ 1.07 $ 0.07 2015 Real estate rental revenue $ 74,856 $ 74,226 $ 78,243 $ 79,102 Net income (loss) $ 29,398 $ (2,886 ) $ 580 $ 62,095 Net income (loss) attributable to the controlling interests $ 29,506 $ (2,546 ) $ 647 $ 62,133 Net income (loss) per share Basic $ 0.43 $ (0.04 ) $ 0.01 $ 0.91 Diluted $ 0.43 $ (0.04 ) $ 0.01 $ 0.91 (1) With regard to per share calculations, the sum of the quarterly results may not equal full year results due to rounding. (2) The second and third quarters of 2016 include gains on sale of real estate classified as continued operations of $24.1 million and $77.6 million , respectively. The first, second and fourth quarters of 2015 include gains on sale of real estate classified as continuing operations of $30.3 million , $1.5 million and $59.4 million , respectively. (3) The second quarter of 2015 includes a real estate impairment of $5.9 million .

Shareholders' Equity

Shareholders' Equity	12 Months Ended
	Dec. 31, 2016
Stockholders' Equity Note [Abstract]
Shareholders' Equity	SHAREHOLDERS' EQUITY During the second quarter of 2016, we issued approximately 5.3 million common shares, including 0.7 million shares issued pursuant to the underwriters' over-allotment option, at a price to the public of $28.20 per share. We received net proceeds of approximately $143.4 million . During the second quarter of 2015, we entered into four separate equity distribution agreements (collectively, the “Equity Distribution Agreements”) with each of Wells Fargo Securities, LLC, BNY Mellon Capital Markets, LLC, Citigroup Global Markets Inc. and RBC Capital Markets, LLC relating to the issuance and sale of up to $200.0 million of our common shares from time to time. Sales of our common shares are made at market prices prevailing at the time of sale. We use net proceeds from the sale of common shares under this program for general corporate purposes, including, without limitation, working capital, the acquisition, renovation, expansion, improvement, development or redevelopment of income producing properties or the repayment of debt. During the 2016, we issued 0.9 million common shares under the Equity Distribution Agreements at a weighted average price of $33.32 per share, raising $29.6 million in net proceeds. We did not issue any shares under the Equity Distribution Agreements during 2015. The Equity Distribution Agreements replace Washington REIT’s prior sales agency financing agreement ("Prior ATM") with BNY Mellon Capital Markets, LLC, which expired by its terms in June 2015. During 2015 and 2014, Washington REIT issued 0.2 million and 1.1 million common shares, respectively, at a weighted average price of $28.34 and $27.86 , respectively, for net proceeds of $5.2 million and $30.7 million , respectively. We have a dividend reinvestment program, whereby shareholders may use their dividends and optional cash payments to purchase common shares. The common shares sold under this program may either be common shares issued by us or common shares purchased in the open market. Net proceeds under this program are used for general corporate purposes. During the 2016, we issued approximately 23,000 common shares under this program at a weighted average price of $30.98 per share, raising $0.7 million in net proceeds.

Deferred Costs

Deferred Costs	12 Months Ended
	Dec. 31, 2016
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Deferred Costs	DEFERRED COSTS As of December 31, 2016 and 2015 , deferred leasing costs and deferred leasing incentives were included in prepaid expenses and other assets as follows (in thousands): December 31, 2016 2015 Gross Carrying Value Accumulated Amortization Net Gross Carrying Value Accumulated Amortization Net Deferred leasing costs $ 58,391 $ 22,748 $ 35,643 $ 59,382 $ 22,897 $ 36,485 Deferred leasing incentives 21,157 8,061 13,096 18,701 6,066 12,635 Amortization, including write-offs, of deferred leasing costs and deferred leasing incentives from continuing operations for the three years ended December 31, 2016 were as follows (in thousands): Year Ended December 31, 2016 2015 2014 Deferred leasing costs amortization $ 6,076 $ 5,983 $ 4,699 Deferred leasing incentives amortization 2,994 2,848 1,704

Schedule II

Schedule II	12 Months Ended
	Dec. 31, 2016
Valuation and Qualifying Accounts [Abstract]
Schedule II	SCHEDULE II VALUATION AND QUALIFYING ACCOUNTS FOR THE YEARS ENDED DECEMBER 31, 2016 , 2015 AND 2014 (IN THOUSANDS) Balance at Beginning of Year Additions Charged to Expenses Net Deductions (Recoveries) Balance at End of Year Allowance for doubtful accounts 2016 $ 2,297 $ 1,706 $ (1,626 ) $ 2,377 2015 $ 3,392 $ 1,368 $ (2,463 ) $ 2,297 2014 $ 6,783 $ 1,402 $ (4,793 ) $ 3,392 Valuation allowance for deferred tax assets 2016 $ 5,705 $ — $ (2,823 ) $ 2,882 2015 $ 5,714 $ — $ (9 ) $ 5,705 2014 $ 5,741 $ — $ (27 ) $ 5,714

Schedule III

Schedule III	12 Months Ended
	Dec. 31, 2016
SEC Schedule III, Real Estate and Accumulated Depreciation Disclosure [Abstract]
Schedule III	SCHEDULE III Initial Cost (b) Net Improvements (Retirement) since Acquisition Gross Amounts at Which Carried at December 31, 2016 Accumulated Depreciation at December 31, 2016 Properties Location Land Buildings and Improvements Land Buildings and Improvements Total (c) Year of Construction Date of Acquisition Net Rentable Square Feet (e) Units Depreciation Life (d) Multifamily Properties 3801 Connecticut Avenue Washington, DC $ 420,000 $ 2,678,000 $ 14,548,000 $ 420,000 $ 17,226,000 $ 17,646,000 $ 10,671,000 1951 Jan 1963 178,000 307 30 years Roosevelt Towers Virginia 336,000 1,996,000 12,261,000 336,000 14,257,000 14,593,000 9,491,000 1964 May 1965 170,000 191 40 years Park Adams Virginia 287,000 1,654,000 11,904,000 287,000 13,558,000 13,845,000 9,444,000 1959 Jan 1969 173,000 200 35 years The Ashby at McLean Virginia 4,356,000 17,102,000 22,576,000 4,356,000 39,678,000 44,034,000 23,631,000 1982 Aug 1996 274,000 256 30 years Walker House Apartments Maryland 2,851,000 7,946,000 7,157,000 2,851,000 15,103,000 17,954,000 10,751,000 1971 Mar 1996 157,000 212 30 years Bethesda Hill Apartments Maryland 3,900,000 13,412,000 13,280,000 3,900,000 26,692,000 30,592,000 17,788,000 1986 Nov 1997 225,000 195 30 years Bennett Park Virginia 2,861,000 917,000 80,226,000 4,774,000 79,230,000 84,004,000 31,960,000 2007 Feb 2001 214,000 224 28 years The Clayborne Virginia 269,000 — 30,858,000 699,000 30,428,000 31,127,000 13,831,000 2008 Jun 2003 60,000 74 26 years The Kenmore (a) Washington, DC 28,222,000 33,955,000 11,422,000 28,222,000 45,377,000 73,599,000 12,152,000 1948 Sep 2008 268,000 374 30 years The Maxwell Virginia 12,787,000 — 38,013,000 12,851,000 37,949,000 50,800,000 4,571,000 2014 Jun 2011 139,000 163 30 years The Paramount Virginia 8,568,000 38,716,000 2,073,000 8,568,000 40,789,000 49,357,000 5,774,000 1984 Oct 2013 141,000 135 30 years Yale West (a) Washington, DC 14,684,000 62,069,000 549,000 14,684,000 62,618,000 77,302,000 6,480,000 2011 Feb 2014 238,000 216 30 years The Wellington Virginia 30,548,000 116,563,000 4,137,000 30,548,000 120,700,000 151,248,000 6,325,000 1960 Jul 2015 842,000 711 30 years Wellington Land Parcel (Trove) (f) Virginia 15,000,000 — 3,952,000 — 18,952,000 18,952,000 — n/a Jul 2015 — n/a n/a Riverside Apartments Virginia 38,924,000 184,854,000 5,857,000 38,924,000 190,711,000 229,635,000 4,288,000 1971 May 2016 1,266,000 1,222 30 years Riverside Apartments Land Parcel (f) Virginia 15,968,000 — 441,000 — 16,409,000 16,409,000 — n/a May 2016 — n/a n/a $ 179,981,000 $ 481,862,000 $ 259,254,000 $ 151,420,000 $ 769,677,000 $ 921,097,000 $ 167,157,000 4,345,000 4,480 Office Buildings 1901 Pennsylvania Avenue Washington, DC $ 892,000 $ 3,481,000 $ 18,275,000 $ 892,000 $ 21,756,000 $ 22,648,000 $ 16,292,000 1960 May 1977 102,000 28 years 515 King Street Virginia 4,102,000 3,931,000 7,795,000 4,102,000 11,726,000 15,828,000 5,775,000 1966 Jul 1992 75,000 50 years 1220 19th Street Washington, DC 7,803,000 11,366,000 15,973,000 7,802,000 27,340,000 35,142,000 15,403,000 1976 Nov 1995 103,000 30 years 1600 Wilson Boulevard Virginia 6,661,000 16,742,000 27,930,000 6,661,000 44,672,000 51,333,000 22,661,000 1973 Oct 1997 169,000 30 years Silverline Center Virginia 12,049,000 71,825,000 98,303,000 12,049,000 170,128,000 182,177,000 77,829,000 1972 Nov 1997 546,000 30 years Courthouse Square Virginia — 17,096,000 9,369,000 — 26,465,000 26,465,000 14,252,000 1979 Oct 2000 118,000 30 years 1776 G Street Washington, DC 31,500,000 54,327,000 7,448,000 31,500,000 61,775,000 93,275,000 29,983,000 1979 Aug 2003 265,000 30 years Monument II Virginia 10,244,000 65,205,000 9,115,000 10,244,000 74,320,000 84,564,000 25,520,000 2000 Mar 2007 208,000 30 years 2000 M Street Washington, DC — 61,101,000 21,696,000 — 82,797,000 82,797,000 27,776,000 1971 Dec 2007 231,000 30 years 2445 M Street Washington, DC 46,887,000 106,743,000 6,210,000 46,887,000 112,953,000 159,840,000 36,583,000 1986 Dec 2008 290,000 30 years 925 Corporate Drive Virginia 4,518,000 24,801,000 1,080,000 4,518,000 25,881,000 30,399,000 8,538,000 2007 Jun 2010 134,000 30 years 1000 Corporate Drive Virginia 4,897,000 25,376,000 (249,000 ) 4,898,000 25,126,000 30,024,000 7,867,000 2009 Jun 2010 136,000 30 years 1140 Connecticut Avenue Washington, DC 25,226,000 50,495,000 13,123,000 25,226,000 63,618,000 88,844,000 16,015,000 1966 Jan 2011 183,000 30 years 1227 25th Street Washington, DC 17,505,000 21,319,000 4,507,000 17,505,000 25,826,000 43,331,000 6,998,000 1988 Mar 2011 136,000 30 years Braddock Metro Center Virginia 18,817,000 71,250,000 10,978,000 18,818,000 82,227,000 101,045,000 20,104,000 1985 Sep 2011 348,000 30 years John Marshall II Virginia 13,490,000 53,024,000 2,841,000 13,490,000 55,865,000 69,355,000 11,536,000 1996 Sep 2011 223,000 30 years Fairgate at Ballston Virginia 17,750,000 29,885,000 5,327,000 17,750,000 35,212,000 52,962,000 7,288,000 1988 Jun 2012 143,000 30 years Army Navy Building (a), (g) Washington, DC 30,796,000 39,315,000 4,885,000 30,796,000 44,200,000 74,996,000 5,633,000 1912 Mar 2014 108,000 30 years 1775 Eye Street, NW Washington, DC 48,086,000 51,074,000 7,833,000 48,086,000 58,907,000 106,993,000 7,593,000 1964 May 2014 186,000 30 years $ 301,223,000 $ 778,356,000 $ 272,439,000 $ 301,224,000 $ 1,050,794,000 $ 1,352,018,000 $ 363,646,000 3,704,000 Initial Cost (b) Net Improvements (Retirement) since Acquisition Gross Amounts at Which Carried at December 31, 2016 Accumulated Depreciation at December 31, 2016 Properties Location Land Buildings and Improvements Land Buildings and Improvements Total (c) Year of Construction Date of Acquisition Net Rentable Square Feet (e) Units Depreciation Life (d) Retail Centers Takoma Park Maryland $ 415,000 $ 1,084,000 $ 332,000 $ 415,000 $ 1,416,000 $ 1,831,000 $ 1,194,000 1962 Jul 1963 51,000 50 years Westminster Maryland 519,000 1,775,000 9,839,000 519,000 11,614,000 12,133,000 7,614,000 1969 Sep 1972 150,000 37 years Concord Centre Virginia 413,000 850,000 5,845,000 413,000 6,695,000 7,108,000 3,414,000 1960 Dec 1973 76,000 33 years Wheaton Park Maryland 796,000 857,000 4,740,000 796,000 5,597,000 6,393,000 3,931,000 1967 Sep 1977 74,000 50 years Bradlee Shopping Center Virginia 4,152,000 5,383,000 14,205,000 4,152,000 19,588,000 23,740,000 11,579,000 1955 Dec 1984 172,000 40 years Chevy Chase Metro Plaza Washington, DC 1,549,000 4,304,000 8,245,000 1,549,000 12,549,000 14,098,000 6,908,000 1975 Sep 1985 50,000 50 years Shoppes of Foxchase Virginia 5,838,000 2,979,000 14,868,000 5,838,000 17,847,000 23,685,000 7,298,000 1960 Jun 1994 134,000 50 years Frederick County Square Maryland 6,561,000 6,830,000 5,295,000 6,561,000 12,125,000 18,686,000 7,828,000 1973 Aug 1995 227,000 30 years 800 S. Washington Street Virginia 2,904,000 5,489,000 5,954,000 2,904,000 11,443,000 14,347,000 5,123,000 1951 Jun 1998 46,000 30 years Centre at Hagerstown Maryland 13,029,000 25,415,000 2,610,000 13,029,000 28,025,000 41,054,000 13,856,000 2000 Jun 2002 331,000 30 years Frederick Crossing Maryland 12,759,000 35,477,000 2,265,000 12,759,000 37,742,000 50,501,000 15,769,000 1999 Mar 2005 295,000 30 years Randolph Shopping Center Maryland 4,928,000 13,025,000 1,154,000 4,928,000 14,179,000 19,107,000 5,288,000 1972 May 2006 82,000 30 years Montrose Shopping Center Maryland 11,612,000 22,410,000 2,196,000 11,020,000 25,198,000 36,218,000 9,289,000 1970 May 2006 145,000 30 years Gateway Overlook Maryland 28,816,000 52,249,000 622,000 29,110,000 52,577,000 81,687,000 16,408,000 2007 Dec 2010 220,000 30 years Olney Village Center (a) Maryland 15,842,000 39,133,000 1,970,000 15,842,000 41,103,000 56,945,000 8,252,000 1979 Aug 2011 199,000 30 years Spring Valley Village (g) Washington, DC 10,836,000 32,238,000 1,913,000 10,836,000 34,151,000 44,987,000 2,871,000 1941 Oct 2014 78,000 30 years $ 120,969,000 $ 249,498,000 $ 82,053,000 $ 120,671,000 $ 331,849,000 $ 452,520,000 $ 126,622,000 2,330,000 Total $ 602,173,000 $ 1,509,716,000 $ 613,746,000 $ 573,315,000 $ 2,152,320,000 $ 2,725,635,000 $ 657,425,000 10,379,000 4,480 a) At December 31, 2016 , our properties were encumbered by non-recourse mortgage amounts as follows: $32.9 million on The Kenmore, $14.9 million on Olney Village Center, $47.1 million on Yale West, and $49.6 million on The Amy Navy Building (prepaid at par in February 2017). Mortgage amounts exclude premiums and debt loan costs. b) The purchase cost of real estate investments has been divided between land and buildings and improvements on the basis of management’s determination of the fair values. c) At December 31, 2016 , total land, buildings and improvements are carried at $2,151.4 million for federal income tax purposes. d) The useful life shown is for the main structure. Buildings and improvements are depreciated over various useful lives ranging from 3 to 50 years. e) Residential properties are presented in gross square feet. f) As of December 31, 2016 , Washington REIT had under development multifamily properties, the Wellington land parcel (Trove) and Riverside Apartments land parcel. The value not yet placed into service at December 31, 2016 was $19.0 million and $16.4 million , respectively. g) As of December 31, 2016 , Washington REIT had investments in various development and redevelopment projects, including Army Navy Building and Spring Valley Village. The total value of these various projects not yet placed in service is $4.8 million at December 31, 2016 . The following is a reconciliation of real estate assets and accumulated depreciation for the three years ended December 31, 2016 (in thousands): Year Ended December 31, 2016 2015 2014 Real estate assets Balance, beginning of period $ 2,673,891 $ 2,547,188 $ 2,289,509 Additions: Property acquisitions (1) 240,499 162,702 289,140 Improvements (1) 66,840 50,954 98,250 Deductions: Impairment write-down — (5,909 ) — Write-off of disposed assets (1,272 ) (3,291 ) (2,857 ) Property sales (254,323 ) (77,753 ) (126,854 ) Balance, end of period $ 2,725,635 $ 2,673,891 $ 2,547,188 Accumulated depreciation Balance, beginning of period $ 692,608 $ 640,434 $ 611,408 Additions: Depreciation 88,347 86,536 77,741 Deductions: Write-off of disposed assets (486 ) (2,408 ) (2,549 ) Property sales (123,044 ) (31,954 ) (46,166 ) Balance, end of period $ 657,425 $ 692,608 $ 640,434 (1) Includes non-cash accruals for capital items and assumed mortgages.

Accounting Policies (Policy)

Accounting Policies (Policy)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Principles of Consolidation and Basis of Presentation	Principles of Consolidation and Basis of Presentation The accompanying audited consolidated financial statements include the consolidated accounts of Washington REIT, our majority-owned subsidiaries and entities in which Washington REIT has a controlling interest, including where Washington REIT has been determined to be a primary beneficiary of a variable interest entity (“VIE”). See note 3 for additional information on the properties for which there is a noncontrolling interest. All intercompany balances and transactions have been eliminated in consolidation. We have prepared the accompanying audited consolidated financial statements pursuant to the rules and regulations of the Securities and Exchange Commission.
Use of Estimates in the Financial Statements	Use of Estimates in the Financial Statements The preparation of financial statements in conformity with Generally Accepted Accounting Principles ("GAAP") requires management to make certain estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In January 2017, the Financial Accounting Standards Board (the "FASB") issued Accounting Standards Update No. 2017-01, Business Combinations (Topic 805) - Clarifying the Definition of a Business , which adds guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions of assets or businesses. Under the new guidance, a set of transferred assets and activities is not a business when substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or group of similar identifiable assets. If a set of transferred assets and activities does not meet this threshold, then an entity must evaluate whether the set meets the requirement that a business include, at a minimum, an input and a substantive process that together significantly contribute to the ability to create outputs. The new standard is effective for public entities for fiscal years beginning after December 15, 2017 and for interim periods therein. Early adoption of the standard is allowed for transactions that have not been reported in financial statements issued prior to the new standards issuance date. Prior to the new guidance, we accounted for acquisitions of operating properties as business combinations, but generally expect that future acquisitions of operating properties will be accounted for as asset acquisitions under the new guidance. Acquisition costs are capitalized in asset acquisitions but expensed in business combinations. Identifiable assets, liabilities assumed and any noncontrolling interests are recognized and measured as of the acquisition date at fair value in a business combination, but are measured by allocating the cost of the acquisition on a relative fair value basis in an asset acquisition. In November 2016, the FASB issued Accounting Standards Update No. 2016-18, Statement of Cash Flows (Topic 230) - Restricted Cash , which requires that restricted cash and cash equivalents be included with cash and cash equivalents when reconciling beginning-of-period and end-of-period total amounts shown on the consolidated statements of cash flows. The new standard is effective for public entities for fiscal years beginning after December 15, 2017 and for interim periods therein, with early adoption permitted. We are currently evaluating the impact the new standard may have on Washington REIT’s consolidated financial statements. In August 2016, the FASB issued Accounting Standards Update No. 2016-15, Classification of Certain Cash Receipts and Cash Payments , which provides specific guidance on how cash receipts and payments should be presented and classified in the statement of cash flows for eight specific issues. The new standard is effective for public entities for fiscal years beginning after December 15, 2017 and for interim periods therein, with early adoption permitted. We are currently evaluating the impact the new standard may have on Washington REIT’s consolidated financial statements. In June 2016, the FASB issued Accounting Standards Update No. 2016-13, Measurement of Credit Losses on Financial Instruments , which requires financial assets measured at an amortized cost basis, including trade receivables, to be presented at the net amount expected to be collected. The new standard is effective for public entities for fiscal years beginning after December 15, 2019 and for interim periods therein with adoption one year earlier permitted. We are currently evaluating the impact the new standard may have on Washington REIT’s consolidated financial statements. In March 2016, the FASB issued Accounting Standards Update No. 2016-09, Improvements to Employee Share-Based Payment Accounting ("ASU 2016-09"), which amends existing accounting standards for employee share-based payments, including by allowing an employer to make a policy election to account for forfeitures as they occur or to continue to provide for an estimate as currently required. ASU 2016-09 also allows an employer to withhold shares in a net settlement in an amount that does not exceed the maximum statutory tax rate in the employees' tax jurisdiction without causing liability classification, and clarifies that all cash payments made to taxing authorities on the employees' behalf for withheld shares should be presented as financing activities on the consolidated statements of cash flows. ASU 2016-09 is effective for public entities for fiscal years beginning after December 15, 2016 and for interim periods therein with early adoption permitted. We adopted ASU 2016-09 as of December 31, 2016 and elected to account for forfeitures as they occur. In accordance with ASU 2016-09, we used the modified retrospective transition method for this election, resulting in a charge to retained earnings of less than $0.1 million . Regarding the cash payments made to taxing authorities on the employees' behalf for withheld shares, we had previously presented such payments as operating activities on our consolidated statements of cash flows, and have applied this change retrospectively. The impact of the implementation of ASU 2016-09 on our consolidated statements of cash flows is as follows (in thousands): Year Ended December 31, 2016 2015 2014 Net cash provided by operating activities (prior to adoption of ASU 2016-09) $ 114,971 $ 107,355 $ 80,701 Reclassification of cash payments for withheld shares 1,960 2,071 2,416 Net cash provided by operating activities (after adoption of ASU 2016-09) $ 116,931 $ 109,426 $ 83,117 Net cash used in financing activities (prior to adoption of ASU 2016-09) $ (68,859 ) $ (6,339 ) $ (87,335 ) Reclassification of cash payments for withheld shares (1,960 ) (2,071 ) (2,416 ) Net cash used in financing activities (after adoption of ASU 2016-09) $ (70,819 ) $ (8,410 ) $ (89,751 ) In February 2016, the FASB issued Accounting Standards Update No. 2016-05, Derivatives and Hedging (Topic 815) , which clarifies that a change in the counterparty to a derivative instrument that has been designated as the hedging instrument under Topic 815, in and of itself, does not require dedesignation of that hedging relationship provided that all other hedging criteria continue to be met. The new standard is effective for public entities for fiscal years beginning after December 15, 2016 and for interim periods therein with early adoption permitted. We do not expect the new standard to have a material impact on Washington REIT’s consolidated financial statements. In February 2016, the FASB issued Accounting Standards Update No. 2016-02, Leases (Topic 842) ("ASU 2016-02") , which amends existing accounting standards for lease accounting, including by requiring lessees to recognize most leases on the balance sheet and making certain changes to lessor accounting. The new standard is effective for public entities for fiscal years beginning after December 15, 2018 and for interim periods therein with early adoption permitted. Upon adoption, for leases in which we are the lessor, the lease contract will be separated into lease and non-lease components in accordance with the provisions outlined within ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) ("ASU 2014-09"). The lease component of the contract will be recognized on a straight-line basis in accordance with ASU 2016-02, while the non-lease component will be recognized under the provisions of ASU 2014-09. For lease contracts with a duration of more than one year in which we are the lessee, the present value of future lease payments will be recognized on our balance sheet as a right-of-use asset and a corresponding lease liability. Also, only direct leasing costs may be capitalized under the new standard, while current accounting standards allow for the capitalization of indirect leasing costs. We are currently evaluating the impact ASU 2016-02 may have on Washington REIT’s consolidated financial statements. In February 2015, the FASB issued Accounting Standards Update No. 2015-02, Consolidation (Topic 810) , which changes the analysis an entity must perform to determine whether it should consolidate certain types of legal entities. Specifically, the new standard i) modifies the evaluation of whether limited partnerships and similar legal entities are variable interest entities ("VIEs") or voting interest entities, ii) eliminates the presumption that a general partner should consolidate a limited partnership and iii) affects the consolidation analysis of reporting entities that are involved with VIEs, particularly those that have fee arrangements and related party relationships. The new standard is effective for public entities for fiscal years beginning after December 15, 2015 and for interim periods therein. We adopted the new standard on January 1, 2016, and the provisions of the new standard did not have any impact on the consolidation of our legal entities. In August 2014, the FASB issued ASU No. 2014-15, Presentation of Financial Statements - Going Concern (Subtopic 205-40) , which provides guidance on management's responsibility to evaluate whether there is substantial doubt about an entity's ability to continue as a going concern and to provide related footnote disclosures. Under the new standard, if conditions or events raise substantial doubt about an entity's ability to continue as a going concern, and substantial doubt is not alleviated after consideration of management's plans, an entity should include a statement in the footnotes indicating that there is substantial doubt about the entity's ability to continue as a going concern. The new standard is effective for fiscal years ending after December 15, 2016 and for annual and interim periods thereafter. We adopted the new standard during the fourth quarter of 2016 and the adoption did not require any disclosures about our ability to continue as a going concern. In June 2014, the FASB issued ASU 2014-09, which creates a single source of revenue guidance. The new standard provides accounting guidance for all revenue arising from contracts with customers and affects all entities that enter into contracts to provide goods or services to their customers (unless the contracts are in the scope of other GAAP requirements, such as the leasing literature). The guidance also provides a model for the measurement and recognition of gains and losses on the sale of certain nonfinancial assets, such as property and equipment, including real estate. The new standard is effective for public entities for fiscal years beginning after December 15, 2017 and for interim periods therein. Early adoption is permitted for public entities beginning after December 15, 2016. We intend to adopt the new standard using the modified retrospective method. Upon adoption of ASU 2016-02, Leases (Topic 842), the majority of our revenue will be subject to the allocation provisions outlined within the revenue standard. We are currently evaluating the specific implementation requirements for allocating the consideration within our contracts in accordance with ASU No. 2014-09. We do not expect the new standard to have a material impact on the measurement and recognition of gains and losses on the sale of properties.
Revenue Recognition	Revenue Recognition We lease multifamily properties under operating leases with terms of generally one year or less. We lease commercial properties (our office and retail segments) under operating leases with an average term of seven years. Substantially all commercial leases contain fixed escalations or, in some instances, changes based on the Consumer Price Index, which occur at specified times during the term of the lease. We recognize rental income and rental abatements from our multifamily and commercial leases when earned on a straight-line basis over the lease term. Recognition of rental income commences when control of the leased space has been given to the tenant. We recognize sales of real estate at closing only when sufficient down payments have been obtained, possession and other attributes of ownership have been transferred to the buyer and we have no significant continuing involvement. We recognize cost reimbursement income from pass-through expenses on an accrual basis over the periods in which the expenses were incurred. Pass-through expenses are comprised of real estate taxes, operating expenses and common area maintenance costs which are reimbursed by tenants in accordance with specific allowable costs per tenant lease agreements. Parking revenues are derived from leases, monthly parking agreements and transient parking. We recognize parking revenues from leases on a straight-line basis over the lease term and other parking revenues as earned.
Accounts Receivable and Allowance for Doubtful Accounts	Accounts Receivable and Allowance for Doubtful Accounts Accounts receivable primarily represents amounts accrued and unpaid from tenants in accordance with the terms of the respective leases, subject to our revenue recognition policy. We review receivables monthly and establish reserves when, in the opinion of management, collection of the receivable is doubtful. We establish reserves for tenants whose rent payment histories or financial conditions cast doubt upon the tenants’ abilities to perform under their lease obligations. When we determine the collection of a receivable to be doubtful in the same quarter that we established the receivable, we recognize the allowance for that receivable as an offset to real estate revenues. When we determine a receivable that was initially established in a prior quarter to be doubtful, we recognize the allowance as an operating expense in Real estate expenses in the consolidated statements of income. In addition to rents due currently, accounts receivable include amounts representing minimal rental income accrued on a straight-line basis to be paid by tenants over the remaining term of their respective leases.
Debt Issuance Costs	Debt Issuance Costs We amortize external debt issuance costs using the effective interest rate method or the straight-line method which approximates the effective interest rate method, over the estimated life of the related debt. We record debt issuance costs related to notes and mortgage notes, net of amortization, on our consolidated balance sheets as an offset to their related debt. We record debt issuance costs related to revolving lines of credit on our consolidated balance sheets with Prepaid expenses and other assets, regardless of whether a balance on the line of credit is outstanding. We record the amortization of all debt issuance costs as interest expense.
Deferred Leasing Costs	Deferred Leasing Costs We capitalize and amortize costs associated with the successful negotiation of leases, both external commissions and internal direct costs, on a straight-line basis over the terms of the respective leases. We record the amortization of deferred leasing costs in Depreciation and amortization on the consolidated statements of income. If an applicable lease terminates prior to the expiration of its initial lease term, we write off the carrying amount of the costs to amortization expense. We capitalize and amortize against revenue leasing incentives associated with the successful negotiation of leases on a straight-line basis over the terms of the respective leases. We record the amortization of deferred leasing incentives as a reduction of revenue. If an applicable lease terminates prior to the expiration of its initial lease term, we write off the carrying amount of the costs as a reduction of revenue.
Real Estate and Depreciation	Real Estate and Depreciation We depreciate buildings on a straight-line basis over estimated useful lives ranging from 28 to 50 years. We capitalize all capital improvements associated with replacements, improvements or major repairs to real property that extend its useful life and depreciate them using the straight-line method over their estimated useful lives ranging from 3 to 30 years. We also capitalize costs incurred in connection with our development projects, including capitalizing interest incurred on borrowing obligations and other internal costs during periods in which qualifying expenditures have been made and activities necessary to get the development projects ready for their intended use are in progress. Capitalization of these costs begin when the activities and related expenditures commence and cease when the project is substantially complete and ready for its intended use, at which time the project is placed in service and depreciation commences. In addition, we capitalize tenant leasehold improvements when certain criteria are met, including when we supervise construction and will own the improvements. We depreciate all tenant improvements over the shorter of the useful life of the improvements or the term of the related tenant lease. Real estate depreciation expense from continuing operations was $84.1 million , $80.7 million , $71.4 million during the years ended December 31, 2016 , 2015 and 2014 , respectively. We charge maintenance and repair costs that do not extend an asset’s useful life to expense as incurred. Interest expense and interest capitalized to real estate assets related to development and major renovation activities for the three years ended December 31, 2016 were as follows (in thousands): Year Ended December 31, 2016 2015 2014 Total interest incurred $ 53,794 $ 60,204 $ 61,927 Capitalized interest (668 ) (658 ) (2,142 ) Interest expense, net of capitalized interest $ 53,126 $ 59,546 $ 59,785 We recognize impairment losses on long-lived assets used in operations, development assets or land held for future development, if indicators of impairment are present and the net undiscounted cash flows estimated to be generated by those assets are less than the assets' carrying amount and estimated undiscounted cash flows associated with future development expenditures. If such carrying amount is in excess of the estimated undiscounted cash flows from the operation and disposal of the property, we would recognize an impairment loss equivalent to an amount required to adjust the carrying amount to its estimated fair value, calculated in accordance with current GAAP fair value provisions. Assets held for sale are recorded at the lower of cost or fair value less costs to sell. We record acquired or assumed assets, including physical assets and in-place leases, and liabilities, based on their fair values. We determine the fair values of acquired buildings on an “as-if-vacant” basis considering a variety of factors, including the replacement cost of the property, estimated rental and absorption rates, estimated future cash flows and valuation assumptions consistent with current market conditions. We determine the fair value of land acquired based on comparisons to similar properties that have been recently marketed for sale or sold. The fair value of in-place leases consists of the following components – (a) the estimated cost to us to replace the leases, including foregone rents during the period of finding a new tenant and foregone recovery of tenant pass-throughs (referred to as “absorption cost”); (b) the estimated cost of tenant improvements, and other direct costs associated with obtaining a new tenant (referred to as “tenant origination cost”); (c) estimated leasing commissions associated with obtaining a new tenant (referred to as “leasing commissions”); (d) the above/at/below market cash flow of the leases, determined by comparing the projected cash flows of the leases in place, including consideration of renewal options, to projected cash flows of comparable market-rate leases (referred to as “net lease intangible”); and (e) the value, if any, of customer relationships, determined based on our evaluation of the specific characteristics of each tenant’s lease and our overall relationship with the tenant (referred to as “customer relationship value”). We have attributed no value to customer relationships as of December 31, 2016 and 2015 . We discount the amounts used to calculate net lease intangibles using an interest rate which reflects the risks associated with the leases acquired. We classify tenant origination costs as Income producing property on our consolidated balance sheets and amortize the tenant origination costs as depreciation expense on a straight-line basis over the remaining life of the underlying leases. We classify leasing commissions and absorption costs as other assets and amortize leasing commissions and absorption costs as amortization expense on a straight-line basis over the remaining life of the underlying leases. We classify net lease intangible assets as other assets and amortize them on a straight-line basis as a decrease to real estate rental revenue over the remaining term of the underlying leases. We classify net lease intangible liabilities as other liabilities and amortize them on a straight-line basis as an increase to real estate rental revenue over the remaining term of the underlying leases. If any of the fair value of below market lease intangibles includes fair value associated with a renewal option, such amounts are not amortized until the renewal option is executed, else the related value is expensed at that time. Should a tenant terminate its lease, we accelerate the amortization of the unamortized portion of the tenant origination cost, leasing commissions, absorption costs and net lease intangible associated with that lease, over its new, shorter term.
Discontinued Operations	Discontinued Operations We classify properties as held for sale when they meet the necessary criteria, which include: (a) senior management commits to and actively embarks upon a plan to sell the assets, (b) the sale is expected to be completed within one year under terms usual and customary for such sales and (c) actions required to complete the plan indicate that it is unlikely that significant changes to the plan will be made or that the plan will be withdrawn. We generally consider that a property has met these criteria when a sale of the property has been approved by the board of trustees, or a committee with authorization from the board of trustees, there are no known significant contingencies related to the sale and management believes it is probable that the sale will be completed within one year. Depreciation on these properties is discontinued at the time they are classified as held for sale, but operating revenues, operating expenses and interest expense continue to be recognized until the date of sale. Under ASU No. 2014-08, Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity , which we adopted as of January 1, 2014, revenues and expenses of properties that are either sold or classified as held for sale are presented as discontinued operations for all periods presented in the consolidated statements of income if the dispositions represent a strategic shift that has (or will have) a major effect on our operations and financial results. Interest on debt that can be identified as specifically attributed to these properties is included in discontinued operations. If the dispositions do not represent a strategic shift that has (or will have) a major effect on our operations and financial results, then the revenues and expenses of the properties that are classified as sold or held for sale are presented as continuing operations in the consolidated statements of income for all periods presented. The provisions of ASU No. 2014-08 apply only to properties classified as held for sale or sold after our adoption date of January 1, 2014.
Segments	Segments We evaluate performance based upon net operating income from the combined properties in each segment. Our reportable operating segments are consolidations of similar properties. GAAP requires that segment disclosures present the measure(s) used by the chief operating decision maker for purposes of assessing segments’ performance. Net operating income is a key measurement of our segment profit and loss. Net operating income is defined as segment real estate rental revenue less segment real estate expenses.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents include cash and commercial paper with original maturities of 90 days or less. We maintain cash deposits with financial institutions that at times exceed applicable insurance limits. We reduce this risk by maintaining such deposits with high quality financial institutions that management believes are credit-worthy.
Restricted Cash	Restricted Cash Restricted cash includes funds escrowed for tenant security deposits, real estate tax, insurance and mortgage escrows and escrow deposits required by lenders on certain of our properties to be used for future building renovations or tenant improvements.
Earnings Per Common Share	Earnings Per Common Share We determine “Basic earnings per share” using the two-class method as our unvested restricted share awards and units have non-forfeitable rights to dividends, and are therefore considered participating securities. We compute basic earnings per share by dividing net income attributable to the controlling interest less the allocation of undistributed earnings to unvested restricted share awards and units by the weighted-average number of common shares outstanding for the period. We also determine “Diluted earnings per share” under the two-class method with respect to the unvested restricted share awards. We further evaluate any other potentially dilutive securities at the end of the period and adjust the basic earnings per share calculation for the impact of those securities that are dilutive. Our dilutive earnings per share calculation includes the dilutive impact of employee stock options based on the treasury stock method and our performance share units under the contingently issuable method.
Stock based Compensation	Stock Based Compensation We currently maintain equity based compensation plans for trustees, officers and employees. We recognize compensation expense for service-based share awards ratably over the period from the service inception date through the vesting period based on the fair market value of the shares on the date of grant. If an award's service inception date precedes the grant date, we initially measure compensation expense for awards with performance conditions at fair value at the service inception date based on probability of payout, and we remeasure compensation expense at subsequent reporting dates until all of the award’s key terms and conditions are known and the grant date is established. We amortize awards with performance conditions using the graded expense method. We measure compensation expense for awards with market conditions based on the grant date fair value, as determined using a Monte Carlo simulation, and we amortize the expense ratably over the requisite service period, regardless of whether the market conditions are achieved and the awards ultimately vest. Compensation expense for the trustee grants, which fully vest immediately, is fully recognized upon issuance based upon the fair market value of the shares on the date of grant.
Accounting for Uncertainty in Income Taxes	Accounting for Uncertainty in Income Taxes We can recognize a tax benefit only if it is “more likely than not” that a particular tax position will be sustained upon examination or audit. To the extent that the “more likely than not” standard has been satisfied, the benefit associated with a tax position is measured as the largest amount that is greater than 50% likely of being recognized upon settlement. As of December 31, 2016 and 2015, we did not have any unrecognized tax benefits. We do not believe that there will be any material changes to our uncertain tax positions over the next twelve months. We are subject to federal income tax as well as income tax of the states of Maryland and Virginia, and the District of Columbia. However, as a REIT, we generally are not subject to income tax on our taxable income to the extent it is distributed as dividends to our shareholders. Tax returns filed for 2012 through 2016 tax years are subject to examination by taxing authorities. We classify interest and penalties related to uncertain tax positions, if any, in our financial statements as a component of general and administrative expense.
Derivatives	Derivatives We borrow funds at a combination of fixed and variable rates. Borrowings under our revolving credit facility and term loans bear interest at variable rates. Our interest rate risk management objectives are to minimize interest rate fluctuation on long-term indebtedness and limit the impact of interest rate changes on earnings and cash flows. To achieve these objectives, from time to time, we may enter into interest rate hedge contracts such as collars, swaps, caps and treasury lock agreements in order to mitigate our interest rate risk with respect to various debt instruments. We generally do not hold or issue these derivative contracts for trading or speculative purposes. The interest rate swaps we enter into are recorded at fair value on a recurring basis. We assess effectiveness of our cash flow hedges both at inception and on an ongoing basis. The effective portion of changes in fair value of the interest rate swaps associated with our cash flow hedges is recorded in accumulated other comprehensive income (loss). Our cash flow hedges become ineffective if critical terms of the hedging instrument and the debt instrument such as notional amounts, settlement dates, reset dates, calculation period and LIBOR do not perfectly match. In addition, we evaluate the default risk of the counterparty by monitoring the creditworthiness of the counterparty. When ineffectiveness of a cash flow hedge exists, the ineffective portion of changes in fair value of the interest rate swaps associated with our cash flow hedges is recognized in earnings in the period affected.

Nature of Business (Tables)

Nature of Business (Tables)	12 Months Ended
	Dec. 31, 2016
Discontinued Operations and Disposal Groups [Abstract]
Schedule of Dispositions	During the three years ended December 31, 2016 , we sold our interests in the following properties (in thousands): Disposition Date Property Type Gain on Sale May 26, 2016 Dulles Station II (1) Office $ 527 June 27, 2016 Maryland Office Portfolio Transaction I (2) Office 23,585 September 22, 2016 Maryland Office Portfolio Transaction II (3) Office 77,592 Total 2016 $ 101,704 March 20, 2015 Country Club Towers Multifamily $ 30,277 September 9, 2015 1225 First Street (4) Multifamily — October 21, 2015 Munson Hill Towers Multifamily 51,395 December 14, 2015 Montgomery Village Center Retail 7,981 Total 2015 $ 89,653 January 21, 2014 Medical Office Portfolio Transactions III & IV (5) Medical Office $ 105,985 May 2, 2014 5740 Columbia Road Retail 570 Total 2014 $ 106,555 (1) Land held for future development and an interest in a parking garage. (2) Maryland Office Portfolio Transaction I consists of 6110 Executive Boulevard, 600 Jefferson Plaza, Wayne Plaza and West Gude Drive. (3) Maryland Office Portfolio Transaction II consists of 51 Monroe Street and One Central Plaza. (4) Interest in land held for future development. (5) Medical Office Portfolio Transactions III & IV consist of Woodburn Medical Park I and II and Prosperity Medical Center I, II and III.
Taxable Percentage of Dividends Paid	The following is a breakdown of the taxable percentage of our dividends for these years ended December 31, 2016, 2015 and 2014 (unaudited): 2016 2015 2014 Ordinary income 66 % 78 % 40 % Return of capital 33 % 22 % 52 % Qualified dividends — % — % — % Unrecaptured Section 1250 gain 1 % — % 8 % Capital gain — % — % — %

Accounting Policies (Tables)

Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Schedule of New Accounting Pronouncements and Changes in Accounting Principles	The impact of the implementation of ASU 2016-09 on our consolidated statements of cash flows is as follows (in thousands): Year Ended December 31, 2016 2015 2014 Net cash provided by operating activities (prior to adoption of ASU 2016-09) $ 114,971 $ 107,355 $ 80,701 Reclassification of cash payments for withheld shares 1,960 2,071 2,416 Net cash provided by operating activities (after adoption of ASU 2016-09) $ 116,931 $ 109,426 $ 83,117 Net cash used in financing activities (prior to adoption of ASU 2016-09) $ (68,859 ) $ (6,339 ) $ (87,335 ) Reclassification of cash payments for withheld shares (1,960 ) (2,071 ) (2,416 ) Net cash used in financing activities (after adoption of ASU 2016-09) $ (70,819 ) $ (8,410 ) $ (89,751 )
Capitalized Interest Expense	Interest expense and interest capitalized to real estate assets related to development and major renovation activities for the three years ended December 31, 2016 were as follows (in thousands): Year Ended December 31, 2016 2015 2014 Total interest incurred $ 53,794 $ 60,204 $ 61,927 Capitalized interest (668 ) (658 ) (2,142 ) Interest expense, net of capitalized interest $ 53,126 $ 59,546 $ 59,785
Components of Fair Value of In-Place Leases	Balances, net of accumulated depreciation or amortization, as appropriate, of the components of the fair value of in-place leases at December 31, 2016 and 2015 were as follows (in thousands): December 31, 2016 2015 Gross Carrying Value Accumulated Amortization Net Gross Carrying Value Accumulated Amortization Net Tenant origination costs $ 54,352 $ 44,823 $ 9,529 $ 55,664 $ 41,138 $ 14,526 Leasing commissions/absorption costs 101,311 86,210 15,101 97,678 75,014 22,664 Net lease intangible assets 18,903 14,193 4,710 19,655 12,434 7,221 Net lease intangible liabilities 33,687 25,359 8,328 34,027 23,444 10,583 Below-market ground lease intangible asset 12,080 1,714 10,366 12,080 1,524 10,556 Amortization of these combined components during the three years ended December 31, 2016 , 2015 and 2014 was as follows (in thousands): Year Ended December 31, 2016 2015 2014 Depreciation and amortization expense $ 17,655 $ 22,244 $ 19,854 Real estate rental revenue, net 410 538 456 $ 18,065 $ 22,782 $ 20,310
Components of Fair Value of In-Place Leases - Future Amortization	Amortization of these combined components over the next five years is projected to be as follows (in thousands): Depreciation and amortization expense Real estate rental revenue, net decrease (increase) Total 2017 $ 8,874 $ (148 ) $ 8,726 2018 6,096 (633 ) 5,463 2019 3,572 (525 ) 3,047 2020 2,357 (320 ) 2,037 2021 1,411 (313 ) 1,098
Reclassification Schedule	Prior year amounts have been reclassified to conform with current year presentation as follows (in thousands): Year Ended December 31, 2015 2014 Utilities $ 18,004 $ 18,056 Real estate taxes 37,152 33,436 Repairs and maintenance 14,095 13,375 Property administration and management 23,099 20,460 Operating services and common area maintenance 15,974 15,068 Other real estate expenses 3,910 3,300 Real estate expenses $ 112,234 $ 103,695

Real Estate Investments (Tables

Real Estate Investments (Tables)	12 Months Ended
	Dec. 31, 2016
Real Estate [Abstract]
Schedule of Real Estate Properties	As of December 31, 2016 and 2015 , our real estate investment portfolio, at cost, consists of properties as follows (in thousands): December 31, 2016 2015 Office $ 1,349,378 $ 1,554,334 Multifamily 885,084 641,424 Retail 450,941 442,039 $ 2,685,403 $ 2,637,797
Schedule of Development Costs	The cost of our real estate portfolio under development or held for future development as of December 31, 2016 and 2015 is as follows (in thousands): December 31, 2016 2015 Office $ 2,640 $ 18,711 Multifamily 36,013 16,307 Retail 1,579 1,076 $ 40,232 $ 36,094
Schedule Of Real Estate Property Acquired	Properties and land for development acquired during the three years ended December 31, 2016 were as follows: Acquisition Date Property Type # of units (unaudited) Rentable Square Feet (unaudited) Contract Purchase Price (in thousands) May 20, 2016 Riverside Apartments Multifamily 1,222 N/A $ 244,750 July 1, 2015 The Wellington Multifamily 711 N/A $ 167,000 February 21, 2014 Yale West Multifamily 216 N/A $ 73,000 March 26, 2014 The Army Navy Building Office N/A 108,000 79,000 May 1, 2014 1775 Eye Street, NW Office N/A 185,000 104,500 October 1, 2014 Spring Valley Retail Center Retail N/A 75,000 40,500 Total 2014 216 368,000 $ 297,000
Revenue and Earnings From Acquisition	The revenue and earnings of our acquisitions during their year of acquisition for the three years ended December 31, 2016 are as follows (in thousands): Year Ended December 31, 2016 2015 2014 Real estate rental revenue $ 13,112 $ 6,797 $ 16,260 Net loss (1,688 ) (2,748 ) (3,168 )
Total Purchase Price Of Acquisitions	We have recorded the total purchase price of the above acquisitions as follows (in thousands): 2016 2015 2014 Land $ 38,924 $ 30,548 $ 104,403 Land held for development 15,968 15,000 — Buildings 184,854 116,563 172,671 Tenant origination costs — — 9,377 Leasing commissions/absorption costs 4,992 4,889 16,474 Net lease intangible assets 22 — 7,331 Net lease intangible liabilities (10 ) — (8,323 ) Fair value of assumed mortgage — — (107,125 ) Furniture, fixtures & equipment — — 932 Total $ 244,750 $ 167,000 $ 195,740
Business Acquisition, Pro Forma Information	The following unaudited pro-forma combined condensed statements of operations set forth the consolidated results of operations for the years ended December 31, 2016 and 2015 as if the above described acquisition in 2016 had occurred on January 1, 2015. The pro forma adjustments exclude acquisition costs directly related to the above-described acquisition. The unaudited pro-forma information does not purport to be indicative of the results that actually would have occurred if the acquisition had been in effect for the years ended December 31, 2016 and 2015 . The unaudited data presented is in thousands, except per share data. Year Ended December 31, 2016 2015 Real estate revenues $ 321,386 $ 327,605 Net income $ 127,439 $ 90,040 Diluted earnings per share $ 1.76 $ 1.31
schedule of assets in joint venture	As of December 31, 2016 and 2015 , The Maxwell's assets were as follows (in thousands): December 31, 2016 2015 Land $ 12,851 $ 12,851 Income producing property 37,949 37,791 Accumulated depreciation and amortization (4,571 ) (2,347 ) Other assets 456 1,188 $ 46,685 $ 49,483
Schedule Of Accounts Payable And Accrued Liabilities Of Joint Ventures	As of December 31, 2016 and 2015 , The Maxwell's liabilities were as follows (in thousands): December 31, 2016 2015 Mortgage notes payable, net $ 31,869 (1) $ 32,214 Accounts payable and other liabilities 186 256 Tenant security deposits 99 82 $ 32,154 $ 32,552
Schedule of Dispositions	We sold our interests in the following properties during the three years ended December 31, 2016 : Disposition Date Property Segment # of units (unaudited) Rentable Contract Gain on Sale May 26, 2016 Dulles Station, Phase II (1) Office N/A N/A $ 12,100 $ 527 June 27, 2016 Maryland Office Portfolio Transaction I (2) Office N/A 692,000 111,500 23,585 September 22, 2016 Maryland Office Portfolio Transaction II (3) Office N/A 491,000 128,500 77,592 Total 2016 1,183,000 $ 252,100 $ 101,704 March 20, 2015 Country Club Towers Multifamily 227 N/A $ 37,800 $ 30,277 September 9, 2015 1225 First Street (4) Multifamily N/A N/A 14,500 — October 21, 2015 Munson Hill Towers Multifamily 279 N/A 57,050 51,395 December 14, 2015 Montgomery Village Center Retail N/A 197,000 27,750 7,981 Total 2015 506 197,000 $ 137,100 $ 89,653 January 21, 2014 Medical Office Portfolio Transactions III & IV (5) Medical Office N/A 427,000 $ 193,561 $ 105,985 May 2, 2014 5740 Columbia Road Retail N/A 3,000 1,600 570 Total 2014 N/A 430,000 $ 195,161 $ 106,555 (1) Land held for future development and an interest in a parking garage. (2) Maryland Office Portfolio Transaction I consists of 6110 Executive Boulevard, 600 Jefferson Plaza, Wayne Plaza and West Gude Drive. (3) Maryland Office Portfolio Transaction II consists of 51 Monroe Street and One Central Plaza. (4) Interest in land held for future development. (5) These properties are classified as discontinued operations. All other sold properties are classified as continuing operations.
Schedule of significant disposition	Real estate rental revenue and net income for the Maryland Office Portfolio for the three years ended December 31, 2016 are as follows: Year Ending December 31, 2016 2015 2014 Real estate rental revenue $ 20,266 $ 32,423 $ 31,811 Net income 9,376 9,848 9,352
Schedule of income statement results for medical office segment sold	The impact of the sale of our medical office segment on revenues and net income is summarized as follows (in thousands, except per share data): Year Ending December 31, 2016 2015 2014 Real estate revenues $ — $ — $ 892 Net income — — 546 Basic and diluted net income per share — — 0.01
Disposal Groups, Including Discontinued Operations	Income from properties classified as discontinued operations for the three years ended December 31, 2016 was as follows (in thousands): Year Ending December 31, 2016 2015 2014 Revenues $ — $ — $ 892 Property expenses — — (346 ) $ — $ — $ 546

Mortgage Notes Payable (Tables)

Mortgage Notes Payable (Tables)	12 Months Ended
	Dec. 31, 2016
Notes Payable, Noncurrent [Abstract]
Schedule of Debt	As of December 31, 2016 and 2015 , we had outstanding mortgage notes payable, each collateralized by one or more buildings and related land from our portfolio, as follows (in thousands): December 31, Properties Assumption/Issuance Date (1) Effective Interest Rate (2) 2016 2015 Payoff Date/Maturity Date Army Navy Building (3) 3/26/2014 3.18 % $ 49,618 $ 50,750 2/1/2017 Yale West (4) 2/21/2014 3.75 % 47,078 47,502 1/31/2022 The Maxwell (5) 2/21/2013 2.27 % — 32,248 1/27/2016 John Marshall II (6) 9/15/2011 5.79 % — 51,011 2/8/2016 Olney Village Center 8/30/2011 4.94 % 14,851 16,503 10/1/2023 Kenmore Apartments 2/2/2009 5.37 % 32,938 33,637 3/1/2019 2445 M Street (7) 12/2/2008 7.25 % — 101,866 10/6/2016 3801 Connecticut Avenue, Walker House and Bethesda Hill (8) 5/29/2008 5.71 % — 81,029 6/1/2016 144,485 414,546 Premiums and discounts, net 4,354 4,175 Debt issuance costs, net (299 ) (669 ) $ 148,540 $ 418,052 (1) Each of these mortgages was assumed with the acquisition of the collateralized properties, except for the mortgage notes secured by 3801 Connecticut Avenue, Walker House, Bethesda Hill, Kenmore Apartments, and the construction loan secured by the development project at The Maxwell, which were originally executed by Washington REIT. We record mortgages assumed in an acquisition at fair value. (2) Yield on the assumption/issuance date, including the effects of any premiums, discounts or fair value adjustments on the notes. (3) The note was prepaid without penalty in February 2017. (4) The maturity date of the mortgage note is January 1, 2052, but can be prepaid, without penalty, beginning on January 31, 2022. (5) Interest rate on The Maxwell construction loan was variable, based on LIBOR plus 2.0% . Interest and principal was payable monthly starting March 2016 until the extended maturity date of February 20, 2017, upon which all unpaid principal and interest were payable in full. In January 2016, Washington REIT exercised its right to purchase the construction loan without penalty from the lender (see note 3, under "Variable Interest Entities"). (6) The note was prepaid without penalty in February 2016. (7) Interest only was payable monthly until the note was prepaid without penalty in October 2016. (8) Interest only was payable monthly until the note was repaid without penalty in June 2016.
Schedule of Maturities of Long-term Debt	Scheduled principal payments subsequent to December 31, 2016 are as follows (in thousands): 2017 $ 52,571 2018 3,135 2019 33,909 2020 2,659 2021 2,829 Thereafter 49,382 $ 144,485 The required principal payments as of December 31, 2016 are as follows (in thousands): 2017 $ — 2018 — 2019 — 2020 250,000 2021 150,000 Thereafter 450,000 $ 850,000

Unsecured Lines Of Credit Pay32

Unsecured Lines Of Credit Payable (Tables)	12 Months Ended
	Dec. 31, 2016
Unsecured Debt [Abstract]
Schedule of Revolving Credit Facilities Covenant Compliance	For the three years ended December 31, 2016 , we recognized interest expense (excluding facility fees) and facility fees as follows (in thousands): Year Ended December 31, 2016 2015 2014 Interest expense (excluding facility fees) $ 3,272 $ 2,266 $ 196 Facility fees 1,220 1,241 1,267 The amount of the Revolving Credit Facility unused and available at December 31, 2016 was as follows (in thousands): Committed capacity $ 600,000 Borrowings outstanding (120,000 ) Unused and available $ 480,000 We executed borrowings and repayments on the Revolving Credit Facility during 2016 as follows (in thousands): Balance at December 31, 2015 $ 105,000 Borrowings 651,000 Repayments (636,000 ) Balance at December 31, 2016 $ 120,000 Information related to revolving credit facilities for the three years ended December 31, 2016 as follows (in thousands, except percentage amounts): Year Ended December 31, 2016 2015 2014 Total revolving credit facilities at December 31 $ 600,000 $ 600,000 $ 500,000 Borrowings outstanding at December 31 120,000 105,000 50,000 Weighted average daily borrowings during the year 214,962 167,573 12,849 Maximum daily borrowings during the year 358,000 350,000 55,000 Weighted average interest rate during the year 1.52 % 1.35 % 1.53 % Weighted average interest rate on borrowings outstanding at December 31 1.64 % 1.36 % 1.37 %

Notes Payable (Tables)

Notes Payable (Tables)	12 Months Ended
	Dec. 31, 2016
Notes Payable [Abstract]
Schedule of Long-term Debt Instruments	Our unsecured notes outstanding as of December 31, 2016 were as follows (in thousands): Coupon/Stated Rate Effective Rate (1) Principal Amount Maturity Date (2) 10 Year Unsecured Notes 4.95 % 5.05 % $ 250,000 10/1/2020 2015 Term Loan 1 Month LIBOR + 110 basis points 2.72 % 150,000 3/15/2021 10 Year Unsecured Notes 3.95 % 4.02 % 300,000 10/15/2022 2016 Term Loan 1 Month LIBOR + 165 basis points 2.86 % 100,000 7/21/2023 30 Year Unsecured Notes 7.25 % 7.36 % 50,000 2/25/2028 Total principal 850,000 Premiums and discounts, net (1,971 ) Deferred issuance costs, net (4,945 ) Total $ 843,084 (1) For fixed rate notes, the effective rate represents the yield on issuance date, including the effects of discounts on the notes. For variable rate notes, the effective rate represents the rate as fixed by interest rate derivatives (see note 7 ). (2) No principal amounts are due prior to maturity.
Schedule of Maturities of Long-term Debt	Scheduled principal payments subsequent to December 31, 2016 are as follows (in thousands): 2017 $ 52,571 2018 3,135 2019 33,909 2020 2,659 2021 2,829 Thereafter 49,382 $ 144,485 The required principal payments as of December 31, 2016 are as follows (in thousands): 2017 $ — 2018 — 2019 — 2020 250,000 2021 150,000 Thereafter 450,000 $ 850,000

Derivative Instruments (Tables)

Derivative Instruments (Tables)	12 Months Ended
	Dec. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments	The fair values of the interest rate swaps as of December 31, 2016 and 2015 , are as follows (in thousands): Aggregate Notional Amount Effective Date Fair Value Asset Derivatives Liability Derivatives December 31, December 31, Derivative Instrument Maturity Date 2016 2015 2016 2015 Interest rate swaps $ 150,000 October 15, 2015 March 15, 2021 $ 417 $ — $ — $ 550 Interest rate swaps 150,000 March 31, 2017 July 21, 2023 7,194 N/A — N/A $ 300,000 $ 7,611 $ — $ — $ 550 We record interest rate swaps on our consolidated balance sheets with prepaid expenses and other assets when in a net asset position, and with accounts payable and other liabilities when in a net liability position. The interest rate swaps have been effective since inception. The gains or losses on the effective swaps are recognized in other comprehensive income (loss), as follows (in thousands): Year Ending December 31, 2016 2015 2014 Unrealized gain (loss) on interest rate hedges $ 8,161 $ (550 ) $ —

Fair Value Disclosures (Tables)

Fair Value Disclosures (Tables)	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Financial Assets And Liabilities Measured At Fair Value	The fair values of these assets and liabilities at December 31, 2016 and 2015 were as follows (in thousands): December 31, 2016 December 31, 2015 Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets: SERP $ 1,407 $ — $ 1,407 $ — $ 1,408 $ — $ 1,408 $ — Derivatives 7,611 — 7,611 — — — — — Liabilities: Derivatives — — — — 550 — 550 —
Financial Assets And Liabilities Not Measured At Fair Value	As of December 31, 2016 and 2015 , the carrying values and estimated fair values of our financial instruments were as follows (in thousands): December 31, 2016 2015 Carrying Value Fair Value Carrying Value Fair Value Cash and cash equivalents $ 11,305 $ 11,305 $ 23,825 $ 23,825 Restricted cash 6,317 6,317 13,383 13,383 2445 M Street note receivable 2,089 2,173 3,849 4,275 Mortgage notes payable 148,540 149,997 418,052 426,693 Lines of credit payable 120,000 120,000 105,000 105,000 Notes payable 843,084 873,516 743,181 753,816

Stock Based Compensation (Table

Stock Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2016
Share-based Compensation [Abstract]
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions	The assumptions used to value the officer LTIP awards were as follows: 2016 Awards 2015 Awards 2014 Awards Expected volatility (1) 18.2 % 17.2 - 17.5% 23.2 % Risk-free interest rate (2) 1.32 % 1.0 - 1.1% 0.8 % Expected term (3) 3 and 4 years 3 and 4 years 3 and 4 years Share price at grant date $27.06 $27.66 - $27.76 $24.08 (1) Expected volatility based upon historical volatility of our daily closing share price. (2) Risk-free interest rate based on U.S. treasury constant maturity bonds on the measurement date with a maturity equal to the market condition performance period. (3) Expected term based on the market condition performance period.
Schedule of Restricted Share Awards	The activity for the three years ended December 31, 2016 related to our restricted share awards, excluding those subject to market conditions, was as follows: Shares Wtd Avg Grant Fair Value Unvested at December 31, 2013 129,815 $ 27.06 Granted 210,817 23.93 Vested during year (236,498 ) 25.06 Forfeited (10,467 ) 25.80 Unvested at December 31, 2014 93,667 25.22 Granted 251,642 27.80 Vested during year (212,856 ) 27.18 Forfeited (26,309 ) 26.77 Unvested at December 31, 2015 106,144 27.71 Granted 251,694 26.01 Vested during year (211,771 ) 29.21 Forfeited (38,368 ) 26.14 Unvested at December 31, 2016 107,699 26.47
Performance Share Units with Market Conditions	Stock based awards with market conditions under the LTIP were granted in 2016, 2015 and 2014 with fair market values, as determined using a Monte Carlo simulation, as follows (in thousands): Grant Date Fair Value 2016 Awards 2015 Awards 2014 Awards Restricted Unrestricted Restricted Unrestricted Restricted Unrestricted Relative TSR $ 182 $ 546 $ 191 $ 634 $ 458 $ 1,376 Absolute TSR 82 246 76 254 327 921
Schedule Of Unamortized Value Of Awards With Market Conditions	The unamortized value of these awards with market conditions as of December 31, 2016 was as follows (in thousands): 2016 Awards 2015 Awards 2014 Awards Restricted Unrestricted Restricted Unrestricted Restricted Unrestricted Relative TSR $ 117 $ 314 $ 83 $ 165 $ 33 $ — Absolute TSR 53 142 33 66 19 —

Earnings Per Common Share (Tabl

Earnings Per Common Share (Tables)	12 Months Ended
	Dec. 31, 2016
Earnings Per Share [Abstract]
Computation Of Basic And Diluted Earnings Per Share	The computation of basic and diluted earnings per share for the three years ended December 31, 2016 was as follows (in thousands; except per share data): Year Ended December 31, 2016 2015 2014 Numerator: Income from continuing operations $ 119,288 $ 89,187 $ 5,070 Net loss attributable to noncontrolling interests 51 553 — Allocation of undistributed earnings to unvested restricted share awards and units to continuing operations (310 ) (269 ) 5 Adjusted income from continuing operations attributable to the controlling interests 119,029 89,471 5,075 Income from discontinued operations, including gain on sale of real estate, net of taxes — — 106,531 Net loss attributable to noncontrolling interests — — 38 Allocation of undistributed earnings to unvested restricted share awards and units to discontinued operations — — (322 ) Adjusted income from discontinued operations attributable to the controlling interests — — 106,247 Adjusted net income attributable to the controlling interests $ 119,029 $ 89,471 $ 111,322 Denominator: Weighted average shares outstanding – basic 72,163 68,177 66,795 Effect of dilutive securities: Employee stock options and restricted share awards 176 133 42 Weighted average shares outstanding – diluted 72,339 68,310 66,837 Earnings per common share, basic: Continuing operations $ 1.65 $ 1.31 $ 0.08 Discontinued operations — — 1.59 $ 1.65 $ 1.31 $ 1.67 Earnings per common share, diluted: Continuing operations $ 1.65 $ 1.31 $ 0.08 Discontinued operations — — 1.59 $ 1.65 $ 1.31 $ 1.67 Dividends declared per common share $ 1.20 $ 1.20 $ 1.20

Rentals Under Operating Leases

Rentals Under Operating Leases (Tables)	12 Months Ended
	Dec. 31, 2016
Rentals Under Operating Leases [Abstract]
Schedule of Future Minimum Rental Payments for Operating Leases	As of December 31, 2016 , non-cancelable commercial operating leases provide for minimum rental income were as follows (in thousands): 2017 $ 172,783 2018 153,100 2019 141,158 2020 126,193 2021 100,887 Thereafter 327,421 $ 1,021,542

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2016
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Real Estate Rental Revenue, Percent	Real estate rental revenue as a percentage of the total for each of the reportable operating segments in continuing operations for the three years ended December 31, 2016 was as follows: Year Ended December 31, 2016 2015 2014 Office 53 % 57 % 57 % Multifamily 27 % 22 % 22 % Retail 20 % 21 % 21 %
Percentage of Real Estate Assets by Segment	The percentage of total income producing real estate assets, at cost, for each of the reportable operating segments in continuing operations as of December 31, 2016 and 2015 was as follows: December 31, 2016 2015 Office 50 % 59 % Multifamily 33 % 24 % Retail 17 % 17 %
Reconciliation Of Net Operating Income Of Reportable Segments	The following tables present revenues, net operating income, capital expenditures and total assets for the three years ended December 31, 2016 from these segments, and reconciles net operating income of reportable segments to net income attributable to the controlling interests as reported (in thousands): Year Ended December 31, 2016 Office Retail Multifamily Corporate Consolidated Real estate rental revenue $ 165,934 $ 61,566 $ 85,764 $ — $ 313,264 Real estate expenses 64,405 15,860 34,748 — 115,013 Net operating income $ 101,529 $ 45,706 $ 51,016 $ — $ 198,251 Depreciation and amortization (108,406 ) General and administrative (19,545 ) Casualty gain and real estate impairment (loss), net 676 Acquisition costs (1,178 ) Interest expense (53,126 ) Other income 297 Gain on sale of real estate 101,704 Income tax benefit 615 Net income 119,288 Less: Net loss attributable to noncontrolling interests 51 Net income attributable to the controlling interests $ 119,339 Capital expenditures $ 30,337 $ 8,821 $ 17,936 $ 920 $ 58,014 Total assets $ 1,104,589 $ 352,056 $ 762,695 $ 34,279 $ 2,253,619 Year Ended December 31, 2015 Office Retail Multifamily Corporate and Other Consolidated Real estate rental revenue $ 174,378 $ 63,507 $ 68,542 $ — $ 306,427 Real estate expenses 67,228 15,606 29,400 — 112,234 Net operating income $ 107,150 $ 47,901 $ 39,142 $ — $ 194,193 Depreciation and amortization (108,935 ) General and administrative (20,123 ) Real estate impairment (5,909 ) Acquisition costs (2,056 ) Interest expense (59,546 ) Other income 709 Gain on sale of real estate 91,107 Income tax expense (134 ) Loss on extinguishment of debt (119 ) Net income 89,187 Less: Net income attributable to noncontrolling interests 553 Net income attributable to the controlling interests $ 89,740 Capital expenditures $ 29,745 $ 3,897 $ 7,865 $ 2,129 $ 43,636 Total assets $ 1,265,570 $ 354,123 $ 529,773 $ 41,702 $ 2,191,168 Year Ended December 31, 2014 Office Retail Multifamily Corporate Consolidated Real estate rental revenue $ 166,116 $ 60,263 $ 62,258 $ — $ 288,637 Real estate expenses 63,903 14,022 25,770 — 103,695 Net operating income $ 102,213 $ 46,241 $ 36,488 $ — $ 184,942 Depreciation and amortization (96,011 ) General and administrative (19,644 ) Acquisition costs (5,710 ) Interest expense (59,785 ) Other income 825 Gain on sale of real estate 570 Income tax expense (117 ) Discontinued operations: Income from properties sold or held for sale 546 Gain on sale of real estate 105,985 Net income 111,601 Less: Net income attributable to noncontrolling interests 38 Net income attributable to the controlling interests $ 111,639 Capital expenditures $ 43,128 $ 5,496 $ 9,186 $ 1,719 $ 59,529 Total assets $ 1,283,950 $ 385,074 $ 408,114 $ 31,179 $ 2,108,317

Selected Quarterly Financial 40

Selected Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information	Unaudited financial data by quarter in each of the years ended December 31, 2016 and 2015 were as follows (in thousands, except for per share data): Quarter (1), (2), (3) First Second Third Fourth 2016 Real estate rental revenue $ 77,137 $ 79,405 $ 79,770 $ 76,952 Net income $ 2,379 $ 31,821 $ 79,662 $ 5,426 Net income attributable to the controlling interests $ 2,384 $ 31,836 $ 79,674 $ 5,445 Net income per share Basic $ 0.03 $ 0.44 $ 1.07 $ 0.07 Diluted $ 0.03 $ 0.44 $ 1.07 $ 0.07 2015 Real estate rental revenue $ 74,856 $ 74,226 $ 78,243 $ 79,102 Net income (loss) $ 29,398 $ (2,886 ) $ 580 $ 62,095 Net income (loss) attributable to the controlling interests $ 29,506 $ (2,546 ) $ 647 $ 62,133 Net income (loss) per share Basic $ 0.43 $ (0.04 ) $ 0.01 $ 0.91 Diluted $ 0.43 $ (0.04 ) $ 0.01 $ 0.91 (1) With regard to per share calculations, the sum of the quarterly results may not equal full year results due to rounding. (2) The second and third quarters of 2016 include gains on sale of real estate classified as continued operations of $24.1 million and $77.6 million , respectively. The first, second and fourth quarters of 2015 include gains on sale of real estate classified as continuing operations of $30.3 million , $1.5 million and $59.4 million , respectively. (3) The second quarter of 2015 includes a real estate impairment of $5.9 million .

Deferred Costs (Tables)

Deferred Costs (Tables)	12 Months Ended
	Dec. 31, 2016
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Schedule of Deferred Cost	As of December 31, 2016 and 2015 , deferred leasing costs and deferred leasing incentives were included in prepaid expenses and other assets as follows (in thousands): December 31, 2016 2015 Gross Carrying Value Accumulated Amortization Net Gross Carrying Value Accumulated Amortization Net Deferred leasing costs $ 58,391 $ 22,748 $ 35,643 $ 59,382 $ 22,897 $ 36,485 Deferred leasing incentives 21,157 8,061 13,096 18,701 6,066 12,635
Schedule of Amortization and Write-Offs of Deferred Financing, Leasing, and Leasing Incentive Costs	Amortization, including write-offs, of deferred leasing costs and deferred leasing incentives from continuing operations for the three years ended December 31, 2016 were as follows (in thousands): Year Ended December 31, 2016 2015 2014 Deferred leasing costs amortization $ 6,076 $ 5,983 $ 4,699 Deferred leasing incentives amortization 2,994 2,848 1,704

Nature Of Business (Details)

Nature Of Business (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percentage of Distribution of Ordinary Taxable Income		90.00%
Income tax benefit (expense)		$ 615	$ (134)	$ (117)
Ordinary income		66.00%	78.00%	40.00%
Return of capital		33.00%	22.00%	52.00%
Qualified dividends		0.00%	0.00%	0.00%
Unrecaptured Section 1250 gain		1.00%	0.00%	8.00%
Capital gain		0.00%	0.00%	0.00%
Taxable Reit Subsidiary [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income tax benefit (expense)	$ (700)		$ (100)	$ (100)
Deferred Tax Assets, Net		$ 500	0
Deferred Tax Liabilities		400	700
Valuation Allowance of Deferred Tax Assets [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Valuation Allowances and Reserves, Balance			5,705	5,714	$ 5,741
Valuation Allowances and Reserves, Deductions (Recoveries) Net		2,823	$ 9	$ 27
Valuation Allowance of Deferred Tax Assets [Member] | Taxable Reit Subsidiary [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Valuation Allowances and Reserves, Balance		$ 2,882

Nature Of Business Properties S

Nature Of Business Properties Sold (Details) - USD ($) $ in Thousands		3 Months Ended					12 Months Ended
		Sep. 30, 2016	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of real estate, discontinued operations							$ 0	$ 0	$ 105,985
Gain on sale of real estate, continuing operations		$ 77,600	$ 24,100	$ 59,400	$ 1,500	$ 30,300	101,704	91,107	570
Disposal Group, Including Discontinued Operation, Gain (Loss) on Disposal								89,653	106,555
Country Club Towers [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of real estate, continuing operations								30,277
1225 First Street [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of real estate, continuing operations	[1]							0
Munson Hill Towers [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of real estate, continuing operations								51,395
Montgomery Village Center [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of real estate, continuing operations								$ 7,981
Medical Office Portfolio Transactions III & IV [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of real estate, discontinued operations	[2]								105,985
5740 Columbia Road [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of real estate, continuing operations									$ 570
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | Dulles Station II [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of real estate, continuing operations	[3]						527
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | Maryland Office Portfolio Transaction I [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of real estate, continuing operations	[4]						23,585
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | Maryland Office Portfolio Transaction II [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of real estate, continuing operations	[5]						$ 77,592
[1]	Interest in land held for future development.
[2]	Medical Office Portfolio Transactions III & IV consist of Woodburn Medical Park I and II and Prosperity Medical Center I, II and III.
[3]	Land held for future development and an interest in a parking garage.
[4]	Maryland Office Portfolio Transaction I consists of 6110 Executive Boulevard, 600 Jefferson Plaza, Wayne Plaza and West Gude Drive.
[5]	Maryland Office Portfolio Transaction II consists of 51 Monroe Street and One Central Plaza.

Accounting Policies - Employee

Accounting Policies - Employee share-based payment accounting (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption		$ (35)
Net Cash Provided by (Used in) Operating Activities	$ 116,931	109,426	$ 83,117
Net Cash Provided by (Used in) Financing Activities	(70,819)	(8,410)	(89,751)
Retained Earnings [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption		(35)
Accounting Standards Update 2016-09, Forfeiture Rate Component [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net Cash Provided by (Used in) Operating Activities	116,931	109,426	83,117
Net Cash Provided by (Used in) Financing Activities	(70,819)	(8,410)	(89,751)
Accounting Standards Update 2016-09, Forfeiture Rate Component [Member] | Retained Earnings [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption	100
Scenario, Previously Reported | Accounting Standards Update 2016-09, Forfeiture Rate Component [Member] | Adjustments for New Accounting Principle, Early Adoption [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net Cash Provided by (Used in) Operating Activities	114,971	107,355	80,701
Net Cash Provided by (Used in) Financing Activities	(68,859)	(6,339)	(87,335)
Restatement Adjustment | Accounting Standards Update 2016-09, Forfeiture Rate Component [Member] | Adjustments for New Accounting Principle, Early Adoption [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net Cash Provided by (Used in) Operating Activities	1,960	2,071	2,416
Net Cash Provided by (Used in) Financing Activities	$ (1,960)	$ (2,071)	$ (2,416)

Accounting Policies - Revenue R

Accounting Policies - Revenue Recognition and Accounts Receivable and Allowance (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Property Subject to or Available for Operating Lease [Line Items]
Notes receivable, net	$ 2.4	$ 3.9
Office and Retail
Property Subject to or Available for Operating Lease [Line Items]
Lessor Leasing Arrangements, Operating Leases, Term of Contract	7 years

Accounting Policies - Real Esta

Accounting Policies - Real Estate and Depreciation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Real estate depreciation	$ 84,100	$ 80,700	$ 71,400
Total interest incurred	53,794	60,204	61,927
Capitalized interest	(668)	(658)	(2,142)
Interest expense, net of capitalized interest	$ 53,126	$ 59,546	$ 59,785
Minimum [Member]
Property, Plant and Equipment [Line Items]
Useful Life	3 years
Minimum [Member] | Building [Member]
Property, Plant and Equipment [Line Items]
Useful Life	28 years
Minimum [Member] | Building and Building Improvements [Member]
Property, Plant and Equipment [Line Items]
Useful Life	3 years
Maximum [Member]
Property, Plant and Equipment [Line Items]
Useful Life	50 years
Maximum [Member] | Building [Member]
Property, Plant and Equipment [Line Items]
Useful Life	50 years
Maximum [Member] | Building and Building Improvements [Member]
Property, Plant and Equipment [Line Items]
Useful Life	30 years

Accounting Policies - Fair valu

Accounting Policies - Fair value of in place leases (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Tenant Origination Costs Member
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 54,352	$ 55,664
Finite-Lived Intangible Assets, Accumulated Amortization	44,823	41,138
Finite-Lived Intangible Assets, Net	9,529	14,526
Leasing Commissions Absorption Costs Member
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	101,311	97,678
Finite-Lived Intangible Assets, Accumulated Amortization	86,210	75,014
Finite-Lived Intangible Assets, Net	15,101	22,664
Net Lease Intangible Assets Member
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	18,903	19,655
Finite-Lived Intangible Assets, Accumulated Amortization	14,193	12,434
Finite-Lived Intangible Assets, Net	4,710	7,221
Net Lease Intangible Liabilities Member
Acquired Finite-Lived Intangible Assets [Line Items]
Below Market Lease, Gross	33,687	34,027
Below Market Lease, Accumulated Amortization	25,359	23,444
Below Market Lease, Net	8,328	10,583
Leases, Acquired-in-Place, Below-Market Ground Lease [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	12,080	12,080
Finite-Lived Intangible Assets, Accumulated Amortization	1,714	1,524
Finite-Lived Intangible Assets, Net	$ 10,366	$ 10,556

Accounting Policies - Amortizat

Accounting Policies - Amortization of leased assets acquired (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Deferred leasing costs amortization	$ 6,076	$ 5,983	$ 4,699
Leases, Acquired-in-Place [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Assets	17,655	22,244	19,854
Amortization of above and below Market Leases	410	538	456
Finite-Lived Intangible Assets, Amortization Expense, Net of Revenue	$ 18,065	$ 22,782	$ 20,310

Accounting Policies - Acquired

Accounting Policies - Acquired finite-lived intangible assets (Details) $ in Thousands	Dec. 31, 2016USD ($)
Operating Leases, Future Minimum Payments Receivable [Abstract]
2,016	$ (172,783)
2,017	(153,100)
2,018	(141,158)
2,019	(126,193)
2,020	(100,887)
Leases, Acquired-in-Place [Member]
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	8,874
Finite-Lived Intangible Assets, Amortization Expense, Year Two	6,096
Finite-Lived Intangible Assets, Amortization Expense, Year Three	3,572
Finite-Lived Intangible Assets, Amortization Expense, Year Four	2,357
Finite-Lived Intangible Assets, Amortization Expense, Year Five	1,411
Operating Leases, Future Minimum Payments Receivable [Abstract]
2,016	(148)
2,017	(633)
2,018	(525)
2,019	(320)
2,020	(313)
Finite-Lived Intangible Assets Net of Revenue [Abstract]
Finite-Lived Intangible Assets, Amortization Expense, Net of Revenue, Next Twelve Months	8,726
Finite-Lived Intangible Assets, Amortization Expense, Net of Revenue, Year Two	5,463
Finite-Lived Intangible Assets, Amortization Expense, Net of Revenue, Year Three	3,047
Finite-Lived Intangible Assets, Amortization Expense, Net of Revenue, Year Four	2,037
Finite-Lived Intangible Assets, Amortization Expense, Net of Revenue, Year Five	$ 1,098

Accounting Policies - Reclassif

Accounting Policies - Reclassification Of Real Estate Expenses (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accounting Policies [Abstract]
Utilities			$ 18,004	$ 18,056
Real estate taxes			37,152	33,436
Repairs and maintenance			14,095	13,375
Property administration and management			23,099	20,460
Operating services and common area maintenance			15,974	15,068
Other real estate expenses			3,910	3,300
Real estate expenses		$ 115,013	112,234	103,695
New Accounting Pronouncement, Early Adoption [Line Items]
Income Tax Expense (Benefit)		$ (615)	134	117
Taxable Reit Subsidiary [Member]
New Accounting Pronouncement, Early Adoption [Line Items]
Income Tax Expense (Benefit)	$ 700		$ 100	$ 100

Real Estate Investments - (Narr

Real Estate Investments - (Narrative) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Real Estate [Line Items]
Real estate investment property, at cost	$ 2,685,403	$ 2,637,797
Properties under development or held for future development	40,232	36,094
7900 Westpark Drive [Member]
Real Estate [Line Items]
Real estate investment property, at cost	25,900
The Army Navy Club Building [Member]
Real Estate [Line Items]
Properties under development or held for future development	2,200
The Wellington land parcel [Member]
Real Estate [Line Items]
Properties under development or held for future development	19,000	19,000
Riverside Developments [Member]
Real Estate [Line Items]
Properties under development or held for future development	16,400	16,400
Spring Vally Retail Center [Member]
Real Estate [Line Items]
Properties under development or held for future development	1,100
Office [Member]
Real Estate [Line Items]
Real estate investment property, at cost	1,349,378	1,554,334
Properties under development or held for future development	2,640	18,711
Multifamily [Member]
Real Estate [Line Items]
Real estate investment property, at cost	885,084	641,424
Properties under development or held for future development	36,013	16,307
Retail [Member]
Real Estate [Line Items]
Real estate investment property, at cost	450,941	442,039
Properties under development or held for future development	$ 1,579	$ 1,076

Real Estate Investments - Sched

Real Estate Investments - Schedule of Acquisitions (Details) $ in Thousands	Oct. 02, 2014USD ($)ft²	May 02, 2014USD ($)ft²	Mar. 26, 2014USD ($)ft²	Dec. 31, 2014USD ($)ft²unit	Dec. 31, 2016USD ($)unit	May 20, 2016USD ($)unit	Dec. 31, 2015USD ($)apartment	Jul. 01, 2015USD ($)unit	Feb. 21, 2014USD ($)unit
Real Estate [Line Items]
Units					4,480		506
Real estate investment property, at cost					$ 2,685,403		$ 2,637,797
Riverside Apartments [Member]
Real Estate [Line Items]
Units | unit					1,222	1,222
Wellington [Member]
Real Estate [Line Items]
Units | unit								711
Yale West [Member]
Real Estate [Line Items]
Units | unit					216				216
Property Acquired [Member]
Real Estate [Line Items]
Units | unit				216
Rentable Square Feet | ft²				368,000
Real estate investment property, at cost				$ 297,000
Property Acquired [Member] | Riverside Apartments [Member]
Real Estate [Line Items]
Real estate investment property, at cost						$ 244,750
Property Acquired [Member] | Wellington [Member]
Real Estate [Line Items]
Real estate investment property, at cost								$ 167,000
Property Acquired [Member] | Yale West [Member]
Real Estate [Line Items]
Real estate investment property, at cost									$ 73,000
Property Acquired [Member] | The Army Navy Club Building [Member]
Real Estate [Line Items]
Rentable Square Feet | ft²			108,000
Real estate investment property, at cost			$ 79,000
Property Acquired [Member] | 1775 Eye Street [Member]
Real Estate [Line Items]
Rentable Square Feet | ft²		185,000
Real estate investment property, at cost		$ 104,500
Property Acquired [Member] | Spring Vally Retail Center [Member]
Real Estate [Line Items]
Rentable Square Feet | ft²	75,000
Real estate investment property, at cost	$ 40,500

Real Estate Investments - Reven

Real Estate Investments - Revenue and Earnings of Acquisitions (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Real Estate [Line Items]
Real estate rental revenue	$ 76,952	$ 79,770	$ 79,405	$ 77,137	$ 79,102	$ 78,243	$ 74,226	$ 74,856	$ 313,264	$ 306,427	$ 288,637
Net income	$ 5,426	$ 79,662	$ 31,821	$ 2,379	$ 62,095	$ 580	$ (2,886)	$ 29,398	119,288	89,187	111,601
Property Acquired [Member]
Real Estate [Line Items]
Real estate rental revenue									13,112	6,797	16,260
Net income									$ (1,688)	$ (2,748)	$ (3,168)

Real Estate Investments - Sch54

Real Estate Investments - Schedule of Physical Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Real Estate [Line Items]
Land	$ 38,924	$ 30,548	$ 104,403
Land held for development	15,968	15,000	0
Buildings	184,854	116,563	172,671
Tenant origination costs	0	0	9,377
Leasing commissions/absorption costs	4,992	4,889	16,474
Net lease intangible assets	22	0	7,331
Net lease intangible liabilities	10	0	8,323
Fair value of assumed mortgage	0	0	107,125
Furniture, fixtures & equipment	0	0	932
Property Acquired [Member]
Real Estate [Line Items]
Total	$ 244,750	$ 167,000	$ 195,740

Real Estate Investments - Acqui

Real Estate Investments - Acquisition (Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)note	Dec. 31, 2014USD ($)
Real Estate [Line Items]
Payments to Acquire Real Estate	$ 227,413	$ 151,682	$ 194,536
Number of Mortgage Notes Assumed | note		2
Notes Assumed		$ 100,900
Net Lease Intangible Assets Member | Riverside Apartments [Member]
Real Estate [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	87 months
net lease intangible liability [Member] | Riverside Apartments [Member]
Real Estate [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	43 months
Property Acquired [Member]
Real Estate [Line Items]
Total	$ 244,750	167,000	195,740
Payments to Acquire Real Estate			194,500
Real Estate Investment Property, at Cost, Including Note Payable Assumed		297,000
Property Acquired [Member] | Riverside Apartments [Member]
Real Estate [Line Items]
Other Payments to Acquire Businesses		300
Property Acquired [Member] | Riverside Apartments land parcel [Member]
Real Estate [Line Items]
Payments to Acquire Land		15,000
Property Acquired [Member] | Wellington [Member]
Real Estate [Line Items]
Payments to Acquire Real Estate	227,400
Other Payments to Acquire Businesses	1,400
Property Acquired [Member] | The Wellington land parcel [Member]
Real Estate [Line Items]
Payments to Acquire Land	$ 16,000
Property Acquired [Member] | Yale West [Member]
Real Estate [Line Items]
Other Payments to Acquire Businesses			$ 3,600
Property Acquired [Member] | 1775 Eye Street [Member]
Real Estate [Line Items]
Other Payments to Acquire Businesses		$ 1,900

Real Estate Investments - Pro F

Real Estate Investments - Pro Forma Schedule (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Real Estate [Abstract]
Real estate revenues	$ 321,386	$ 327,605
Net income	$ 127,439	$ 90,040
Diluted earnings per share (in dollars per share)	$ 1.76	$ 1.31

Real Estate Investments - Varia

Real Estate Investments - Variable Interest (Narrative) (Details) $ in Thousands		3 Months Ended	6 Months Ended	12 Months Ended
		Jun. 30, 2015USD ($)	Jun. 30, 2011	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Nov. 30, 2011	Jun. 15, 2011	Aug. 31, 2007a
Real Estate [Line Items]
Casualty (gain) and real estate impairment loss, net		$ (5,900)		$ (676)	$ 5,909	$ 0
Disposal Group, Including Discontinued Operation, Consideration				252,100	137,100	$ 195,161
Loans Payable				$ 144,485	414,546
Maximum [Member]
Real Estate [Line Items]
Ownership percentage				95.00%
4661 Kenmore Avenue [Member]
Real Estate [Line Items]
Land, Acres Held | a									0.8
1225 First Street [Member]
Real Estate [Line Items]
Ownership percentage by noncontrolling owners							5.00%
Six Fifty North Glebe Road [Member]
Real Estate [Line Items]
Ownership percentage			90.00%
Ownership percentage by noncontrolling owners								10.00%
Loans Payable	[1]			$ 0	32,248
Multifamily [Member] | 1225 First Street [Member]
Real Estate [Line Items]
Disposal Group, Including Discontinued Operation, Consideration	[2]				$ 14,500
[1]	Interest rate on The Maxwell construction loan was variable, based on LIBOR plus 2.0%. Interest and principal was payable monthly starting March 2016 until the extended maturity date of February 20, 2017, upon which all unpaid principal and interest were payable in full. In January 2016, Washington REIT exercised its right to purchase the construction loan without penalty from the lender (see note 3, under "Variable Interest Entities").
[2]	Interest in land held for future development.

Real Estate Investments - Joint

Real Estate Investments - Joint Venture on the Balance Sheet and Income Statement (Details) - USD ($) $ in Thousands	Dec. 31, 2016		Dec. 31, 2015
Real Estate [Line Items]
Land	$ 573,315		$ 561,256
Accumulated depreciation and amortization	657,425		692,608
Other assets	40,232		36,094
Mortgage notes payable, net	148,540		418,052
Accounts payable and other liabilities	46,967		45,367
Tenant security deposits	8,802		9,378
Six Fifty North Glebe Road [Member]
Real Estate [Line Items]
Land	12,851		12,851
Income producing property	37,949		37,791
Accumulated depreciation and amortization	4,571		2,347
Other assets	456		1,188
Real Estate Investments, Joint Ventures	46,685		49,483
Mortgage notes payable, net	31,869	[1]	32,214
Accounts payable and other liabilities	186		256
Tenant security deposits	99		82
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	$ 32,154		$ 32,552
[1]	The mortgage notes payable balance as of December 31, 2016 is eliminated in consolidation due to the purchase of the loan by Washington REIT in January 2016.

Real Estate Investments - Prope

Real Estate Investments - Properties Sold (Narrative) (Details) $ in Thousands		3 Months Ended					12 Months Ended
		Sep. 30, 2016USD ($)	Jun. 30, 2016USD ($)ft²	Dec. 31, 2015USD ($)ft²	Jun. 30, 2015USD ($)	Mar. 31, 2015USD ($)	Dec. 31, 2016USD ($)ft²buildingsContracts	Dec. 31, 2015USD ($)ft²	Dec. 31, 2014USD ($)ft²
Real Estate [Line Items]
Disposal Group, Including Discontinued Operation, Consideration				$ 137,100			$ 252,100	$ 137,100	$ 195,161
Area of Real Estate Property | ft²				197,000			1,183,000	197,000	430,000
Gain on sale of real estate, continuing operations		$ 77,600	$ 24,100	$ 59,400	$ 1,500	$ 30,300	$ 101,704	$ 91,107	$ 570
Montrose Shopping Center [Member]
Real Estate [Line Items]
Area of Real Estate Property | ft²			15,000
Disposal Group, Including Discontinued Operation, Sale Price			$ 2,000
Gain on sale of real estate, continuing operations			$ 1,400
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | Dulles Station II [Member]
Real Estate [Line Items]
Gain on sale of real estate, continuing operations	[1]						$ 527
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | Maryland Portfolio [Member]
Real Estate [Line Items]
Number of Buildings Sold | buildings							6
Disposal Group, Held-for-sale or Disposed of by Sale, Not Discontinued Operations [Member] | Maryland Portfolio [Member]
Real Estate [Line Items]
Number of Purchase and Sale Agreements | Contracts							2
Office [Member] | Maryland Portfolio [Member]
Real Estate [Line Items]
Disposal Group, Including Discontinued Operation, Consideration							$ 240,000
Office [Member] | Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | Dulles Station II [Member]
Real Estate [Line Items]
Disposal Group, Including Discontinued Operation, Consideration	[2]						$ 12,100
[1]	Land held for future development and an interest in a parking garage.
[2]	Land held for future development and an interest in a parking garage.

Real Estate Investments - Sch60

Real Estate Investments - Schedule of Properties Sold (Details) $ in Thousands		3 Months Ended					12 Months Ended
		Sep. 30, 2016USD ($)	Jun. 30, 2016USD ($)	Dec. 31, 2015USD ($)ft²apartment	Jun. 30, 2015USD ($)	Mar. 31, 2015USD ($)	Dec. 31, 2016USD ($)ft²unit	Dec. 31, 2015USD ($)ft²apartment	Dec. 31, 2014USD ($)ft²
Real Estate [Line Items]
Units				506			4,480	506
Area of Real Estate Property | ft²				197,000			1,183,000	197,000	430,000
Disposal Group, Including Discontinued Operation, Consideration				$ 137,100			$ 252,100	$ 137,100	$ 195,161
Gain on sale of real estate, continuing operations		$ 77,600	$ 24,100	$ 59,400	$ 1,500	$ 30,300	101,704	91,107	570
Gain on sale of real estate, discontinued operations							0	0	105,985
Disposal Group, Including Discontinued Operation, Gain (Loss) on Disposal								89,653	106,555
Dulles Station II [Member] | Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member]
Real Estate [Line Items]
Gain on sale of real estate, continuing operations	[1]						527
Dulles Station II [Member] | Office [Member] | Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member]
Real Estate [Line Items]
Disposal Group, Including Discontinued Operation, Consideration	[2]						12,100
Maryland Office Portfolio Transaction I [Member] | Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member]
Real Estate [Line Items]
Gain on sale of real estate, continuing operations	[3]						$ 23,585
Maryland Office Portfolio Transaction I [Member] | Office [Member] | Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member]
Real Estate [Line Items]
Area of Real Estate Property | ft²							692,000
Disposal Group, Including Discontinued Operation, Consideration	[4]						$ 111,500
Maryland Office Portfolio Transaction II [Member] | Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member]
Real Estate [Line Items]
Gain on sale of real estate, continuing operations	[5]						$ 77,592
Maryland Office Portfolio Transaction II [Member] | Office [Member] | Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member]
Real Estate [Line Items]
Area of Real Estate Property | ft²							491,000
Disposal Group, Including Discontinued Operation, Consideration							$ 128,500
Country Club Towers [Member]
Real Estate [Line Items]
Gain on sale of real estate, continuing operations								$ 30,277
Country Club Towers [Member] | Multifamily [Member]
Real Estate [Line Items]
Units | apartment				227				227
Disposal Group, Including Discontinued Operation, Consideration				$ 37,800				$ 37,800
1225 First Street [Member]
Real Estate [Line Items]
Gain on sale of real estate, continuing operations	[6]							0
1225 First Street [Member] | Multifamily [Member]
Real Estate [Line Items]
Disposal Group, Including Discontinued Operation, Consideration	[7]			$ 14,500				14,500
Munson Hill Towers [Member]
Real Estate [Line Items]
Gain on sale of real estate, continuing operations								$ 51,395
Munson Hill Towers [Member] | Multifamily [Member]
Real Estate [Line Items]
Units | apartment				279				279
Disposal Group, Including Discontinued Operation, Consideration				$ 57,050				$ 57,050
Montgomery Village Center [Member]
Real Estate [Line Items]
Gain on sale of real estate, continuing operations								$ 7,981
Montgomery Village Center [Member] | Retail [Member]
Real Estate [Line Items]
Area of Real Estate Property | ft²				197,000				197,000
Disposal Group, Including Discontinued Operation, Consideration				$ 27,750				$ 27,750
Medical Office Portfolio Transactions III & IV [Member]
Real Estate [Line Items]
Gain on sale of real estate, discontinued operations	[8]								$ 105,985
Medical Office Portfolio Transactions III & IV [Member] | Medical Office Building [Member]
Real Estate [Line Items]
Area of Real Estate Property | ft²									427,000
Disposal Group, Including Discontinued Operation, Consideration	[9]								$ 193,561
5740 Columbia Road [Member]
Real Estate [Line Items]
Gain on sale of real estate, continuing operations									$ 570
5740 Columbia Road [Member] | Retail [Member]
Real Estate [Line Items]
Area of Real Estate Property | ft²									3,000
Disposal Group, Including Discontinued Operation, Consideration									$ 1,600
[1]	Land held for future development and an interest in a parking garage.
[2]	Land held for future development and an interest in a parking garage.
[3]	Maryland Office Portfolio Transaction I consists of 6110 Executive Boulevard, 600 Jefferson Plaza, Wayne Plaza and West Gude Drive.
[4]	Maryland Office Portfolio Transaction I consists of 6110 Executive Boulevard, 600 Jefferson Plaza, Wayne Plaza and West Gude Drive.
[5]	Maryland Office Portfolio Transaction II consists of 51 Monroe Street and One Central Plaza.
[6]	Interest in land held for future development.
[7]	Interest in land held for future development.
[8]	Medical Office Portfolio Transactions III & IV consist of Woodburn Medical Park I and II and Prosperity Medical Center I, II and III.
[9]	These properties are classified as discontinued operations. All other sold properties are classified as continuing operations.

Real Estate Investments - Real

Real Estate Investments - Real Estate Revenue (Details) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Sep. 30, 2013USD ($)buildingsagreements	Dec. 31, 2016USD ($)$ / shares	Dec. 31, 2015USD ($)$ / shares	Dec. 31, 2014USD ($)$ / shares
Real Estate [Line Items]
Disposal Group, Including Discontinued Operation, Rental Income		$ 20,266	$ 32,423	$ 31,811
Income (Loss) from Individually Significant Component Disposed of or Held-for-sale, Excluding Discontinued Operations, before Income Tax		9,376	9,848	9,352
Net income		0	0	106,531
Income from properties sold or held for sale		0	0	546
Discontinued Properties Member
Real Estate [Line Items]
Real estate revenues		0	0	892
Disposal Group, Including Discontinued Operation, Operating Expense		0	0	346
Medical Office Porfolio [Member]
Real Estate [Line Items]
Number of Purchase and Sale Agreements | agreements	4
Disposal Group, Including Discontinued Operation, Sale Price	$ 500,800
Real estate revenues		0	0	892
Net income		$ 0	$ 0	$ 546
Discontinued operations (in dollars per share) | $ / shares		$ 0	$ 0	$ 0.01
Office [Member] | Medical Office Porfolio [Member]
Real Estate [Line Items]
Number of Buildings Sold | buildings	2

Real Estate Investments - Casua

Real Estate Investments - Casualty Gains (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Real Estate [Line Items]
Casualty (gain) and real estate impairment (loss), net	$ (5,900)	$ (676)	$ 5,909	$ 0
Insurance proceeds		883	0	$ 0
Rents and other receivables, net of allowance for doubtful accounts of $2,377 and $2,297, respectively		64,319	$ 62,890
Bethesda Hill Apartments [Member]
Real Estate [Line Items]
Casualty (gain) and real estate impairment (loss), net		700
Insurance proceeds		900
Rents and other receivables, net of allowance for doubtful accounts of $2,377 and $2,297, respectively		$ 200

Mortgage Notes Payable (Details

Mortgage Notes Payable (Details) $ in Thousands		1 Months Ended	12 Months Ended
		Feb. 28, 2017USD ($)	Dec. 31, 2016USD ($)buildings		Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Mortgage Loans on Real Estate [Line Items]
Collateral for mortgage notes payable | buildings			1
Loans Payable			$ 144,485		$ 414,546
Mortgage notes payable, net			148,540		418,052
Carrying Amount, Mortgaged Properties			280,400		619,400
Repayments of Secured Debt			$ 270,061		4,512	$ 3,954
The Army Navy Club Building [Member]
Mortgage Loans on Real Estate [Line Items]
Debt Instrument, Issuance Date	[1],[2]		Mar. 26, 2014
Effective interest rate percentage	[2],[3]		3.18%
Loans Payable	[2]		$ 49,618		50,750
Debt Instrument, Maturity Date	[2]		Feb. 1, 2017
Yale West [Member]
Mortgage Loans on Real Estate [Line Items]
Debt Instrument, Issuance Date	[1],[4]		Feb. 21, 2014
Effective interest rate percentage	[3],[4]		3.75%
Loans Payable	[4]		$ 47,078		47,502
Debt Instrument, Maturity Date	[4]		Jan. 31, 2022
Six Fifty North Glebe Road [Member]
Mortgage Loans on Real Estate [Line Items]
Debt Instrument, Issuance Date	[1],[5]		Feb. 21, 2013
Effective interest rate percentage	[3],[5]		2.27%
Loans Payable	[5]		$ 0		32,248
Debt Instrument, Maturity Date	[5]		Jan. 27, 2016
Mortgage notes payable, net			$ 31,869	[6]	32,214
John Marshall II Member
Mortgage Loans on Real Estate [Line Items]
Debt Instrument, Issuance Date	[1],[7]		Sep. 15, 2011
Effective interest rate percentage	[3],[7]		5.79%
Loans Payable	[7]		$ 0		51,011
Debt Instrument, Maturity Date	[7]		Feb. 8, 2016
Olney Village Center Member
Mortgage Loans on Real Estate [Line Items]
Debt Instrument, Issuance Date	[1]		Aug. 30, 2011
Effective interest rate percentage	[3]		4.94%
Loans Payable			$ 14,851		16,503
Debt Instrument, Maturity Date			Oct. 1, 2023
Kenmore Apartments [Member]
Mortgage Loans on Real Estate [Line Items]
Debt Instrument, Issuance Date	[1]		Feb. 2, 2009
Effective interest rate percentage	[3]		5.37%
Loans Payable			$ 32,938		33,637
Debt Instrument, Maturity Date			Mar. 1, 2019
2445 M Street [Member]
Mortgage Loans on Real Estate [Line Items]
Debt Instrument, Issuance Date	[1],[8]		Dec. 2, 2008
Effective interest rate percentage	[3],[8]		7.25%
Loans Payable	[8]		$ 0		101,866
Debt Instrument, Maturity Date	[8]		Oct. 6, 2016
3801 Connecticut, Walker House, Bethesda Hill [Member]
Mortgage Loans on Real Estate [Line Items]
Debt Instrument, Issuance Date	[1],[9]		May 29, 2008
Effective interest rate percentage	[3],[9]		5.71%
Loans Payable	[9]		$ 0		81,029
Debt Instrument, Maturity Date	[9]		Jun. 1, 2016
London Interbank Offered Rate (LIBOR) [Member] | Six Fifty North Glebe Road [Member]
Mortgage Loans on Real Estate [Line Items]
Spread on variable rate			2.00%
Mortgage payable
Mortgage Loans on Real Estate [Line Items]
Debt Instrument, Unamortized Discount (Premium), Net			$ 4,354		4,175
Deferred Finance Costs, Net			$ 299		$ 669
Subsequent Event [Member] | The Army Navy Club Building [Member]
Mortgage Loans on Real Estate [Line Items]
Repayments of Secured Debt		$ 49,600
[1]	Each of these mortgages was assumed with the acquisition of the collateralized properties, except for the mortgage notes secured by 3801 Connecticut Avenue, Walker House, Bethesda Hill, Kenmore Apartments, and the construction loan secured by the development project at The Maxwell, which were originally executed by Washington REIT. We record mortgages assumed in an acquisition at fair value.
[2]	The note was prepaid without penalty in February 2017.
[3]	Yield on the assumption/issuance date, including the effects of any premiums, discounts or fair value adjustments on the notes.
[4]	The maturity date of the mortgage note is January 1, 2052, but can be prepaid, without penalty, beginning on January 31, 2022.
[5]	Interest rate on The Maxwell construction loan was variable, based on LIBOR plus 2.0%. Interest and principal was payable monthly starting March 2016 until the extended maturity date of February 20, 2017, upon which all unpaid principal and interest were payable in full. In January 2016, Washington REIT exercised its right to purchase the construction loan without penalty from the lender (see note 3, under "Variable Interest Entities").
[6]	The mortgage notes payable balance as of December 31, 2016 is eliminated in consolidation due to the purchase of the loan by Washington REIT in January 2016.
[7]	The note was prepaid without penalty in February 2016.
[8]	Interest only was payable monthly until the note was prepaid without penalty in October 2016.
[9]	Interest only was payable monthly until the note was repaid without penalty in June 2016.

Mortgage Notes Payable - Schedu

Mortgage Notes Payable - Scheduled Principal Payments (Details) $ in Thousands	Dec. 31, 2016USD ($)
Notes Payable, Noncurrent [Abstract]
2,017	$ 52,571
2,018	3,135
2,019	33,909
2,020	2,659
2,021	2,829
Thereafter	49,382
Total principal	$ 144,485

Unsecured Lines Of Credit Pay65

Unsecured Lines Of Credit Payable - Narrative (Details)	Jun. 23, 2015	Sep. 30, 2016	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Jul. 21, 2016	Sep. 15, 2015
Line of Credit Facility [Line Items]
Total revolving credit facilities at December 31			$ 600,000,000	$ 600,000,000	$ 500,000,000
Weighted average interest rate during the year			1.52%	1.35%	1.53%
U.S. Covered Terrorism Losses, Percent			0.85
Insurance Provider, Covered Terrorism Losses, Percent			0.10
Aggregate Insurance Limit For Terrorism Losses			$ 100,000,000,000
Line of Credit [Member]
Line of Credit Facility [Line Items]
Weighted average interest rate during the year		1.00%
Line of Credit Facility, Commitment Fee Percentage		0.20%
Credit Facility No 1 [Member]
Line of Credit Facility [Line Items]
Total revolving credit facilities at December 31			100,000,000
Credit Facility No 2 [Member]
Line of Credit Facility [Line Items]
Total revolving credit facilities at December 31			400,000,000
credit facility 2015 [Member]
Line of Credit Facility [Line Items]
Total revolving credit facilities at December 31			1,000,000,000
credit facility 2015 [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Total revolving credit facilities at December 31			$ 600,000,000
line of credit facility, number of extensions allowed			2
Line of Credit Facility, extension period			6 months
credit facility 2015 [Member] | 2015 Term Loan [Member]
Line of Credit Facility [Line Items]
Long-term Line of Credit, Noncurrent			$ 150,000,000
Debt Instrument, Term			5 years 6 months
London Interbank Offered Rate (LIBOR) [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Variable Rate			0.77%
London Interbank Offered Rate (LIBOR) [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Spread on variable rate	1.00%
London Interbank Offered Rate (LIBOR) [Member] | 2015 Term Loan [Member]
Line of Credit Facility [Line Items]
Spread on variable rate			1.10%
Federal Funds Effective Swap Rate [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Spread on variable rate	0.50%
Interest Rate Swap [Member]
Line of Credit Facility [Line Items]
Derivative, Number of Instruments Held			2			2	2
Effective interest rate percentage			2.70%
Minimum [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Commitment Fee Percentage	0.125%
Minimum [Member] | London Interbank Offered Rate (LIBOR) [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Spread on variable rate	0.875%
Minimum [Member] | Base Rate [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Spread on variable rate	0.00%
Maximum [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Commitment Fee Percentage	0.30%
Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Spread on variable rate	1.55%
Maximum [Member] | Base Rate [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Spread on variable rate	0.55%

Unsecured Lines Of Credit Pay66

Unsecured Lines Of Credit Payable - Revolving Line of Credit (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Line of Credit Facility [Line Items]
Committed capacity	$ 600,000,000	$ 600,000,000	$ 500,000,000
Borrowings outstanding	120,000,000	105,000,000	$ 50,000,000
credit facility 2015 [Member]
Line of Credit Facility [Line Items]
Committed capacity	1,000,000,000
credit facility 2015 [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Committed capacity	600,000,000
Borrowings outstanding	120,000,000	$ 105,000,000
Unused and available	$ 480,000,000

Unsecured Lines Of Credit Pay67

Unsecured Lines Of Credit Payable - Repayment of Revolving Credit Facility (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)
Line of Credit Facility, Amount Outstanding [Roll Forward]
Long-term Line of Credit	$ 105,000
Long-term Line of Credit	120,000
credit facility 2015 [Member] | Line of Credit [Member]
Line of Credit Facility, Amount Outstanding [Roll Forward]
Long-term Line of Credit	105,000
Proceeds from Lines of Credit	651,000
Repayments of Lines of Credit	636,000
Long-term Line of Credit	$ 120,000

Unsecured Lines Of Credit Pay68

Unsecured Lines Of Credit Payable - Recognized Interest Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Unsecured Debt [Abstract]
Line of Credit Facility, Periodic Payment, Interest	$ 3,272	$ 2,266	$ 196
Line of Credit Facility, Commitment Fee Amount	$ 1,220	$ 1,241	$ 1,267

Unsecured Lines Of Credit Pay69

Unsecured Lines Of Credit Payable - Revolving Credit Facility (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Unsecured Debt [Abstract]
Total revolving credit facilities at December 31	$ 600,000	$ 600,000	$ 500,000
Borrowings outstanding	120,000	105,000	50,000
Weighted average daily borrowings during the year	214,962	167,573	12,849
Maximum daily borrowings during the year	$ 358,000	$ 350,000	$ 55,000
Weighted average interest rate during the year	1.52%	1.35%	1.53%
Weighted average interest rate on borrowings outstanding at December 31	1.64%	1.362%	1.369%

Notes Payable (Details)

Notes Payable (Details) - USD ($)		3 Months Ended	12 Months Ended
		Mar. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Notes Payable			$ 843,084,000	$ 743,181,000
Total principal			144,485,000
Debt Instrument, Periodic Payment, Principal			0
Proceeds from term loan			100,000,000	$ 150,000,000	$ 0
Notes payable
Debt Instrument [Line Items]
Notes Payable			843,084,000
Total principal			850,000,000
Net unamortized discount			(1,971,000)
Debt Issuance Cost			$ (4,945,000)
Notes payable | 10 Year Unsecured Notes 5.053% [Member]
Debt Instrument [Line Items]
Coupon stated rate			4.95%
Effective interest rate percentage	[1]		5.05%
Notes Payable			$ 250,000,000
Debt Instrument, Maturity Date	[2]		Oct. 1, 2020
Notes payable | 2015 Term Loan [Member]
Debt Instrument [Line Items]
Effective interest rate percentage	[1]		2.72%
Long-term Line of Credit, Noncurrent			$ 150,000,000
Debt Instrument, Maturity Date			Mar. 15, 2021
Notes payable | 10 Year Unsecured Notes 3.950 % [Member]
Debt Instrument [Line Items]
Coupon stated rate			3.95%
Effective interest rate percentage	[1]		4.02%
Notes Payable			$ 300,000,000
Debt Instrument, Maturity Date	[2]		Oct. 15, 2022
Notes payable | 2016 Term Loan [Member]
Debt Instrument [Line Items]
Effective interest rate percentage	[1]		2.86%
Long-term Line of Credit, Noncurrent			$ 100,000,000
Debt Instrument, Maturity Date	[2]		Jul. 21, 2023
Debt Instrument, Term			7 years
Debt Instrument, Face Amount			$ 150,000,000
Debt Instrument, Deferred Draw Period			6 months
Proceeds from term loan			$ 100,000,000
Notes payable | 30 Year Unsecured Notes [Member]
Debt Instrument [Line Items]
Coupon stated rate			7.25%
Effective interest rate percentage	[1]		7.36%
Notes Payable			$ 50,000,000
Debt Instrument, Maturity Date	[2]		Feb. 25, 2028
London Interbank Offered Rate (LIBOR) [Member] | 2016 Term Loan [Member]
Debt Instrument [Line Items]
Spread on variable rate			1.00%
London Interbank Offered Rate (LIBOR) [Member] | Notes payable | 2016 Term Loan [Member]
Debt Instrument [Line Items]
Spread on variable rate			1.65%
London Interbank Offered Rate (LIBOR) [Member] | 2015 Term Loan [Member]
Debt Instrument [Line Items]
Spread on variable rate			1.10%
Federal Funds Effective Swap Rate [Member] | 2016 Term Loan [Member]
Debt Instrument [Line Items]
Spread on variable rate			0.50%
Minimum [Member] | London Interbank Offered Rate (LIBOR) [Member] | 2016 Term Loan [Member]
Debt Instrument [Line Items]
Spread on variable rate			1.50%
Minimum [Member] | Base Rate [Member] | 2016 Term Loan [Member]
Debt Instrument [Line Items]
Spread on variable rate			0.50%
Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member] | 2016 Term Loan [Member]
Debt Instrument [Line Items]
Spread on variable rate			2.45%
Maximum [Member] | Base Rate [Member] | 2016 Term Loan [Member]
Debt Instrument [Line Items]
Spread on variable rate			1.45%
Subsequent Event [Member] | Notes payable | 2016 Term Loan [Member]
Debt Instrument [Line Items]
Proceeds from term loan		$ 50,000,000
[1]	For fixed rate notes, the effective rate represents the yield on issuance date, including the effects of discounts on the notes. For variable rate notes, the effective rate represents the rate as fixed by interest rate derivatives (see note 7).
[2]	No principal amounts are due prior to maturity.

Notes Payable - Maturities of N

Notes Payable - Maturities of Notes Payable (Details) $ in Thousands	Dec. 31, 2016USD ($)
Long-term Debt of Registrant, Maturities, Repayments of Principal, Fiscal Year Maturity [Abstract]
2,017	$ 52,571
2,018	3,135
2,019	33,909
2,020	2,659
2,021	2,829
Thereafter	49,382
Total principal	144,485
Notes payable
Long-term Debt of Registrant, Maturities, Repayments of Principal, Fiscal Year Maturity [Abstract]
2,017	0
2,018	0
2,019	0
2,020	250,000
2,021	150,000
Thereafter	450,000
Total principal	$ 850,000

Derivative Instruments - Narrat

Derivative Instruments - Narrative (Details)		12 Months Ended
		Dec. 31, 2016USD ($)Rate	Jul. 21, 2016	Sep. 15, 2015
Derivative [Line Items]
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net		$ 1,200,000
Interest Rate Swap [Member]
Derivative [Line Items]
Derivative, Number of Instruments Held		2	2	2
Derivative, Notional Amount		$ 300,000,000
Effective interest rate percentage		2.70%
Swap [Member]
Derivative [Line Items]
Fair Value Hedge Assets		$ 7,600,000
2015 Term Loan [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Derivative, Notional Amount		$ 150,000,000
Effective interest rate percentage | Rate		2.70%
2016 Term Loan [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Derivative, Notional Amount		$ 150,000,000
Effective interest rate percentage	[1]	2.86%
Debt Instrument, Maturity Date		Jul. 21, 2023
Unsecured Debt [Member] | 2015 Term Loan [Member]
Derivative [Line Items]
Effective interest rate percentage	[1]	2.72%
Debt Instrument, Maturity Date		Mar. 15, 2021
Unsecured Debt [Member] | 2016 Term Loan [Member]
Derivative [Line Items]
Effective interest rate percentage	[1]	2.86%
Debt Instrument, Maturity Date	[2]	Jul. 21, 2023
[1]	For fixed rate notes, the effective rate represents the yield on issuance date, including the effects of discounts on the notes. For variable rate notes, the effective rate represents the rate as fixed by interest rate derivatives (see note 7).
[2]	No principal amounts are due prior to maturity.

Derivative Instruments - Schedu

Derivative Instruments - Schedule of Derivatives (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Derivative [Line Items]
Derivative Liability	$ 0	$ 550,000
Interest Rate Swap [Member]
Derivative [Line Items]
Derivative, Notional Amount	300,000,000
Derivative Asset	7,611,000
Derivative Liability	0	550,000
Swap [Member]
Derivative [Line Items]
Unrealized Gain (Loss) on Derivatives	7,611,000	(550,000)	$ 0
2015 Term Loan [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Derivative, Notional Amount	150,000,000
2016 Term Loan [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Derivative, Notional Amount	150,000,000
Accounts Payable and Other Liabilities [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Derivative Asset	7,611,000	0
Accounts Payable and Other Liabilities [Member] | 2015 Term Loan [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Derivative Asset	417,000	0
Derivative Liability	0	$ 550,000
Accounts Payable and Other Liabilities [Member] | 2016 Term Loan [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Derivative Asset	$ 7,194,000

Fair Value Disclosures (Financi

Fair Value Disclosures (Financial Assets And Liabilities Measured At Fair Value) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
SERP	$ 1,407	$ 1,408
Derivative Liability	$ 0	550
Cash and Cash Equivalents and Restricted Cash Maturity Period	90 days
Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
SERP	$ 0	0
Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
SERP	1,407	1,408
Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
SERP	0	0
Interest Rate Swap [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Asset	7,611
Derivative Liability	0	550
Interest Rate Swap [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Asset	0
Derivative Liability	0	0
Interest Rate Swap [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Asset	7,611
Derivative Liability	0	550
Interest Rate Swap [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Asset	0
Derivative Liability	$ 0	$ 0

Fair Value Disclosures (Finan75

Fair Value Disclosures (Financial Assets And Liabilities Not Measured At Fair Value) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	$ 11,305	$ 23,825	$ 15,827	$ 130,343
Restricted cash	6,317	13,383
Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents		23,825
Restricted cash		13,383
Mortgage notes payable	148,540	418,052
Lines of credit payable	120,000	105,000
Notes payable	843,084	743,181
Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	11,305	23,825
Restricted cash	6,317	13,383
Mortgage notes payable	149,997	426,693
Lines of credit payable	120,000	105,000
Notes payable	873,516	753,816
2445 M Street [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
2445 M Street note receivable	2,089	3,849
2445 M Street [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
2445 M Street note receivable	$ 2,173	$ 4,275

Stock Based Compensation - (Nar

Stock Based Compensation - (Narrative) (Details)	12 Months Ended
	Dec. 31, 2016shares
Washington Real Estate Investment Trust 2016 Omnibus Long Term Incentive Plan [Domain]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized	2,400,000
Washington Real Estate Investment Trust 2007 Omnibus Long Term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized	2,000,000
Plan in effect, period	10 years
Options outstanding	0

Stock Based Compensation - Shor

Stock Based Compensation - Short Term and Long-Term Incentive Plan (Narrative) (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
New STIP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period	1 year
Percentage of Potential Award Based Upon Service Requirement	50.00%
Share-based Compensation Arrangements by Share-based Payment Awards, Options, Vested after Performance Period, Percentage	50.00%
New STIP [Member] | Performance-Based Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
New LTIP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage payable In unrestricted shares	75.00%
Percentage payable in restricted shares	25.00%
Performance period	3 years
Award vesting period	3 years
Grant Date Fair Value as a Percentage of Base Salary on absolute TSR	50.00%	50.00%	50.00%
Grant Date Fair Value as a Percentage of Base Salary on relative TSR	50.00%	50.00%	50.00%
Grant date fair value as a percentage of base salary	150.00%
Total compensation cost not yet recognized, period for recognition	4 years
Weighting for performance measurement based on cumulative 3-Year total shareholder return	50.00%
Weighting for performance measurement based on 20 peer comapnies	50.00%
New LTIP [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant Date Fair Value as a Percentage of Base Salary on absolute TSR	17.00%	13.00%	24.00%
Grant Date Fair Value as a Percentage of Base Salary on relative TSR	38.00%	40.00%	42.00%
Grant date fair value as a percentage of base salary	80.00%
New LTIP [Member] | Minimum [Member] | Share-based Compensation Award, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant Date Fair Value as a Percentage of Base Salary on absolute TSR			10.00%
Grant Date Fair Value as a Percentage of Base Salary on relative TSR			11.00%
New LTIP [Member] | Minimum [Member] | Share-based Compensation Award, Tranche Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant Date Fair Value as a Percentage of Base Salary on absolute TSR			16.00%
Grant Date Fair Value as a Percentage of Base Salary on relative TSR			23.00%
New LTIP [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant Date Fair Value as a Percentage of Base Salary on absolute TSR	30.00%	29.00%	38.00%
Grant Date Fair Value as a Percentage of Base Salary on relative TSR	66.00%	69.00%	67.00%
New LTIP [Member] | Maximum [Member] | Share-based Compensation Award, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant Date Fair Value as a Percentage of Base Salary on absolute TSR			20.00%
Grant Date Fair Value as a Percentage of Base Salary on relative TSR			20.00%
New LTIP [Member] | Maximum [Member] | Share-based Compensation Award, Tranche Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant Date Fair Value as a Percentage of Base Salary on absolute TSR			30.00%
Grant Date Fair Value as a Percentage of Base Salary on relative TSR			43.00%
Cash [Member] | New STIP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage payable In unrestricted shares	100.00%
Cash [Member] | New STIP [Member] | Performance-Based Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage payable In unrestricted shares	50.00%
Restricted Share Units [Member] | New STIP [Member] | Performance-Based Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage payable in restricted shares	50.00%
Restricted Share Units [Member] | New LTIP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period	1 year
Restricted Share Units [Member] | New LTIP [Member] | Performance-Based Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation cost not yet recognized, period for recognition	4 years
Unrestricted Share Awards [Member] | New LTIP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation cost not yet recognized, period for recognition	3 years

Stock Based Compensation - Assu

Stock Based Compensation - Assumptions for LTIP Awards (Details) - New LTIP [Member] - $ / shares		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Apr. 23, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected Volatility Rate				23.20%
Risk Free Interest Rate				0.80%
Share price at grant date					$ 24.08
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected Volatility Rate	[1]	17.20%	17.20%
Risk Free Interest Rate	[2]	1.00%	1.00%
Expected Term	[3]	3 years	3 years	3 years
Share price at grant date		$ 27.66	$ 27.66
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected Volatility Rate	[1]	17.50%	17.50%
Risk Free Interest Rate	[2]	1.10%	1.10%
Expected Term	[3]	4 years	4 years	4 years
Share price at grant date		$ 27.76	$ 27.76
[1]	Expected volatility based upon historical volatility of our daily closing share price.
[2]	Risk-free interest rate based on U.S. treasury constant maturity bonds on the measurement date with a maturity equal to the market condition performance period.
[3]	Expected term based on the market condition performance period.

Stock Based Compensation - Trus

Stock Based Compensation - Trustee Awards and Total Compensation Expense (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation [Abstract]
Trustee share-based compensation	$ 100,000	$ 100,000	$ 55,000
Share-based Compensation Arrangement by Share-based Payment Award Accelerated Compensation Cost	3,500,000	5,100,000	$ 5,000,000
Capitalized Share-based Compensation During Period	$ 100,000	$ 600,000

Stock Based Compensation - Rest

Stock Based Compensation - Restricted Share Awards with Performance and Service Conditions (Details) - Restricted Share Awards [Member] - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Other Than Options, Nonvested, Number, Beginning	106,144	93,667	129,815
Other Than Options, Granted	251,694	251,642	210,817
Other Than Options, Vested During Year	(211,771)	(212,856)	(236,498)
Other Than Options, Forfeited	(38,368)	(26,309)	(10,467)
Other Than Options, Nonvested, Number, Beginning	107,699	106,144	93,667
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Other Than Options, Nonvested, Weighted Average Grant Date Fair Value	$ 27.71	$ 25.22	$ 27.06
Other Than Options, Granted, Weighted Average Grant Date Fair Value	26.01	27.80	23.93
Other Than Options, Vested During Year, Weighted Average Grant Date Fair Value	29.21	27.18	25.06
Other Than Options, Forfeited, Weighted Average Grant Date Fair Value	26.14	26.77	25.80
Other Than Options, Nonvested, Weighted Average Grant Date Fair Value	$ 26.47	$ 27.71	$ 25.22

Stock Based Compensation - Re81

Stock Based Compensation - Restricted Share Awards with Performance and Service Conditions (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of restricted share units vested	$ 6.2	$ 5.8	$ 6.1
Restricted Share Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized	$ 1.9
Total compensation cost not yet recognized, period for recognition	20 months

Stock Based Compensation - Re82

Stock Based Compensation - Restricted and Unrestricted Shares with Market Conditions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Relative TSR [Member] | Restricted Share Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted and Unrestricted Share Awards, Grant Date Fair Value	$ 182	$ 191	$ 458
Unamortized Value Of Restricted and Unrestricted Shares	117	83	33
Relative TSR [Member] | Unrestricted Share Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted and Unrestricted Share Awards, Grant Date Fair Value	546	634	1,376
Unamortized Value Of Restricted and Unrestricted Shares	314	165	0
Absolute TSR [Member] | Restricted Share Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted and Unrestricted Share Awards, Grant Date Fair Value	82	76	327
Unamortized Value Of Restricted and Unrestricted Shares	53	33	19
Absolute TSR [Member] | Unrestricted Share Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted and Unrestricted Share Awards, Grant Date Fair Value	246	254	921
Unamortized Value Of Restricted and Unrestricted Shares	$ 142	$ 66	$ 0

Other Benefit Plans (Details)

Other Benefit Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
401I(k) plan contributions by employer	$ 0.4	$ 0.5	$ 0.4
Other Postretirement Defined Benefit Plan, Liabilities, Noncurrent	0.9	1.7
Pension and Other Postretirement Benefit Expense	0.2	0.3	$ 0.3
Officer [Member]
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Accrued benefit liability	$ 1.3	$ 1.4

Earnings Per Common Share - Com

Earnings Per Common Share - Computation Of Basic And Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2016	[1]	Sep. 30, 2016	[1],[2]	Jun. 30, 2016	[1],[2]	Mar. 31, 2016	[1]	Dec. 31, 2015	[1],[2]	Sep. 30, 2015	[1]	Jun. 30, 2015	[1],[2],[3]	Mar. 31, 2015	[1],[2]	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Income from continuing operations																	$ 119,288	$ 89,187	$ 5,070
Less: Net loss attributable to noncontrolling interests in subsidiaries																	(51)	(553)	(38)
Allocation of undistributed earnings to unvested restricted share awards and units to continuing operations																	310	269	(5)
Adjusted income from continuing operations attributable to the controlling interests																	119,029	89,471	5,075
Income from discontinued operations, including gain on sale of real estate, net of taxes																	0	0	106,531
Allocation of undistributed earnings to unvested restricted share awards and units to discontinued operations																	0	0	(322)
Adjusted income from discontinued operations attributable to the controlling interests																	0	0	106,247
Adjusted net income attributable to the controlling interests																	$ 119,029	$ 89,471	$ 111,322
Weighted average shares outstanding – basic																	72,163	68,177	66,795
Employee stock options and restricted share awards																	176	133	42
Weighted average shares outstanding - diluted																	72,339	68,310	66,837
Continuing operations																	$ 1.65	$ 1.31	$ 0.08
Discontinued operations (in dollars per share)																	0	0	1.59
Basic earnings: Adjusted net income attributable to the controlling interests (in dollars per share)	$ 0.07		$ 1.07		$ 0.44		$ 0.03		$ 0.91		$ 0.01		$ (0.04)		$ 0.43		1.65	1.31	1.67
Continuing operations																	1.65	1.31	0.08
Discontinued operations (in dollars per share)																	0	0	1.59
Net income per share, diluted (in dollars per share)	$ 0.07		$ 1.07		$ 0.44		$ 0.03		$ 0.91		$ 0.01		$ (0.04)		$ 0.43		1.65	1.31	1.67
Common Stock, Dividends, Per Share, Declared																	$ 1.20	$ 1.20	$ 1.20
Continuing Operations [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Less: Net loss attributable to noncontrolling interests in subsidiaries																	$ 51	$ 553	$ 0
Discontinued Operations [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Less: Net loss attributable to noncontrolling interests in subsidiaries																	$ 0	$ 0	$ 38
[1]	With regard to per share calculations, the sum of the quarterly results may not equal full year results due to rounding.
[2]	The second and third quarters of 2016 include gains on sale of real estate classified as continued operations of $24.1 million and $77.6 million, respectively. The first, second and fourth quarters of 2015 include gains on sale of real estate classified as continuing operations of $30.3 million, $1.5 million and $59.4 million, respectively.
[3]	The second quarter of 2015 includes a real estate impairment of $5.9 million.

Rentals Under Operating Lease85

Rentals Under Operating Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating Leased Assets [Line Items]
Tenant Reimbursements	$ 35,200	$ 34,600	$ 31,600
2,016	172,783
2,017	153,100
2,018	141,158
2,019	126,193
2,020	100,887
Thereafter	327,421
Operating Leases, Future Minimum Payments Receivable	$ 1,021,542
Multifamily Properties [Member]
Operating Leased Assets [Line Items]
Lessee Leasing Arrangements, Operating Leases, Term of Contract	1 year

Commitments and Contingencies (

Commitments and Contingencies (Details)	12 Months Ended
	Dec. 31, 2016Contracts
Commitments and Contingencies Disclosure [Abstract]
Development Contracts with Third Parties, Number	0

Segment Information (Details)

Segment Information (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016USD ($)	Sep. 30, 2016USD ($)	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Sep. 30, 2015USD ($)	Jun. 30, 2015USD ($)	Mar. 31, 2015USD ($)	Dec. 31, 2016USD ($)segment	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Segment Reporting Information [Line Items]
Number of Reportable Segments | segment									3
Real estate rental revenue	$ 76,952	$ 79,770	$ 79,405	$ 77,137	$ 79,102	$ 78,243	$ 74,226	$ 74,856	$ 313,264	$ 306,427	$ 288,637
Real estate expenses									115,013	112,234	103,695
Net operating income									198,251	194,193	184,942
Depreciation and amortization									(108,406)	(108,935)	(96,011)
General and administrative									(19,545)	(20,123)	(19,644)
Casualty (gain) and real estate impairment (loss), net							5,900		676	(5,909)	0
Acquisition costs									(1,178)	(2,056)	(5,710)
Interest expense									(53,126)	(59,546)	(59,785)
Other income									297	709	825
Gain on sale of real estate, continuing operations		77,600	24,100		59,400		1,500	30,300	101,704	91,107	570
Income tax benefit (expense)									615	(134)	(117)
Loss on extinguishment of debt									0	(119)	0
Income from properties sold or held for sale									0	0	546
Gain on sale of real estate, discontinued operations									0	0	105,985
Net income	5,426	79,662	31,821	2,379	62,095	580	(2,886)	29,398	119,288	89,187	111,601
Less: Net loss attributable to noncontrolling interests in subsidiaries									(51)	(553)	(38)
Net income attributable to the controlling interests	5,445	$ 79,674	$ 31,836	$ 2,384	62,133	$ 647	$ (2,546)	$ 29,506	119,339	89,740	111,639
Capital expenditures									58,014	43,636	59,529
Total assets	2,253,619				2,191,168				$ 2,253,619	$ 2,191,168	$ 2,108,317
Office [Member]
Segment Reporting Information [Line Items]
Real estate rental revenue as a percentage of total									0.53	0.57	0.57
Percentage of total income producing real estate assets									0.50	0.59
Real estate rental revenue									$ 165,934	$ 174,378	$ 166,116
Real estate expenses									64,405	67,228	63,903
Net operating income									101,529	107,150	102,213
Capital expenditures									30,337	29,745	43,128
Total assets	1,104,589				1,265,570				$ 1,104,589	$ 1,265,570	$ 1,283,950
Retail [Member]
Segment Reporting Information [Line Items]
Real estate rental revenue as a percentage of total									0.20	0.21	0.21
Percentage of total income producing real estate assets									0.17	0.17
Real estate rental revenue									$ 61,566	$ 63,507	$ 60,263
Real estate expenses									15,860	15,606	14,022
Net operating income									45,706	47,901	46,241
Capital expenditures									8,821	3,897	5,496
Total assets	352,056				354,123				$ 352,056	$ 354,123	$ 385,074
Multifamily [Member]
Segment Reporting Information [Line Items]
Real estate rental revenue as a percentage of total									0.27	0.22	0.22
Percentage of total income producing real estate assets									0.33	0.24
Real estate rental revenue									$ 85,764	$ 68,542	$ 62,258
Real estate expenses									34,748	29,400	25,770
Net operating income									51,016	39,142	36,488
Capital expenditures									17,936	7,865	9,186
Total assets	762,695				529,773				762,695	529,773	408,114
Corporate And Other [Member]
Segment Reporting Information [Line Items]
Real estate rental revenue									0	0	0
Real estate expenses									0	0	0
Net operating income									0	0	0
Capital expenditures									920	2,129	1,719
Total assets	$ 34,279				$ 41,702				$ 34,279	$ 41,702	$ 31,179

Selected Quarterly Financial 88

Selected Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2016		Sep. 30, 2016		Jun. 30, 2016		Mar. 31, 2016		Dec. 31, 2015		Sep. 30, 2015		Jun. 30, 2015		Mar. 31, 2015		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Real estate rental revenue	$ 76,952		$ 79,770		$ 79,405		$ 77,137		$ 79,102		$ 78,243		$ 74,226		$ 74,856		$ 313,264	$ 306,427	$ 288,637
Net income	5,426		79,662		31,821		2,379		62,095		580		(2,886)		29,398		119,288	89,187	111,601
Net income attributable to the controlling interests	$ 5,445		$ 79,674		$ 31,836		$ 2,384		$ 62,133		$ 647		$ (2,546)		$ 29,506		$ 119,339	$ 89,740	$ 111,639
Net income per share, Basic (in dollars per share)	$ 0.07	[1]	$ 1.07	[1],[2]	$ 0.44	[1],[2]	$ 0.03	[1]	$ 0.91	[1],[2]	$ 0.01	[1]	$ (0.04)	[1],[2],[3]	$ 0.43	[1],[2]	$ 1.65	$ 1.31	$ 1.67
Net income per share, diluted (in dollars per share)	$ 0.07	[1]	$ 1.07	[1],[2]	$ 0.44	[1],[2]	$ 0.03	[1]	$ 0.91	[1],[2]	$ 0.01	[1]	$ (0.04)	[1],[2],[3]	$ 0.43	[1],[2]	$ 1.65	$ 1.31	$ 1.67
Gain on sale of real estate, continuing operations			$ 77,600		$ 24,100				$ 59,400				$ 1,500		$ 30,300		$ 101,704	$ 91,107	$ 570
Casualty (gain) and real estate impairment loss, net													$ (5,900)				$ (676)	$ 5,909	$ 0
[1]	With regard to per share calculations, the sum of the quarterly results may not equal full year results due to rounding.
[2]	The second and third quarters of 2016 include gains on sale of real estate classified as continued operations of $24.1 million and $77.6 million, respectively. The first, second and fourth quarters of 2015 include gains on sale of real estate classified as continuing operations of $30.3 million, $1.5 million and $59.4 million, respectively.
[3]	The second quarter of 2015 includes a real estate impairment of $5.9 million.

Shareholders' Equity (Details)

Shareholders' Equity (Details) - USD ($)	3 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Jun. 30, 2015
Financing Agreements [Line Items]
Net proceeds from equity offerings		$ 172,936,000	$ 5,215,000	$ 30,690,000
Common stock reserved for future issuance					$ 200,000,000
Shares issued under Dividend Reinvestment Program		$ 700,000
Common Stock [Member]
Financing Agreements [Line Items]
Stock issued during period (in shares)	5,300,000	6,223,000	184,000	1,125,000
Pursuant of underwriter over-allotment (in shares)	693,750
Shares issued (in dollars per share)	$ 28.20
Net proceeds from equity offerings	$ 143,400,000		$ 5,200,000	$ 30,700,000
Common stock, weighted average issued price (in dollars per share)			$ 28.34	$ 27.86
Shares issued under Dividend Reinvestment Program (in shares)		23,000
Stock issued during period, weighted share price, dividend reinstated plan (in dollars per share)		$ 30.98
Shares issued under Dividend Reinvestment Program		$ 700,000
2016 Equity Distribution Agreements [Member] | Common Stock [Member]
Financing Agreements [Line Items]
Stock issued during period (in shares)		900,000
Net proceeds from equity offerings		$ 29,600,000
Stock issued during period, weighted average price (in dollars per share)		$ 33.32

Deferred Costs Schedule of Prep

Deferred Costs Schedule of Prepaid Expenses and Other Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Deferred Costs, Leasing, Gross	$ 58,391	$ 59,382
Deferred Costs, Leasing, Accumulated Amortization	22,748	22,897
Deferred Costs, Leasing, Net	35,643	36,485
Deferred Leasing Incentives, Gross	21,157	18,701
Accumulated Amortization, Deferred Leasing Incentives	8,061	6,066
Deferred Leasing Incentives, Net	$ 13,096	$ 12,635

Deferred Costs Schedule of Amor

Deferred Costs Schedule of Amortization and Write-Offs of Deferred Financing, Leasing, and Leasing Incentive Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Deferred leasing costs amortization	$ 6,076	$ 5,983	$ 4,699
Deferred leasing incentives amortization	$ 2,994	$ 2,848	$ 1,704

Schedule II (Details)

Schedule II (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Allowance for doubtful accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	$ 2,297	$ 3,392	$ 6,783
Additions Charged to Expenses	1,706	1,368	1,402
Net Deductions (Recoveries)	(1,626)	(2,463)	(4,793)
Balance at End of Year	2,377	2,297	3,392
Valuation allowance for deferred tax assets
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	5,705	5,714	5,741
Additions Charged to Expenses	0	0	0
Net Deductions (Recoveries)	$ (2,823)	(9)	(27)
Balance at End of Year		$ 5,705	$ 5,714

Schedule III (Details)

Schedule III (Details) ft² in Thousands		12 Months Ended
		Dec. 31, 2016USD ($)		Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2016USD ($)ft²unit		May 20, 2016unit	Dec. 31, 2015USD ($)apartment	Feb. 21, 2014unit
Real Estate and Accumulated Depreciation [Line Items]
Initial Cost, Land	[1]					$ 602,173,000
Initial Cost, Buildings and Improvements	[1]					1,509,716,000
Net Improvements (Retirement) since Acquisition						613,746,000
Gross Amounts at Which Carried at December 31, 2016, Land						573,315,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						2,152,320,000
Gross Amounts at Which Carried at December 31, 2016, Total		$ 2,673,891,000		$ 2,547,188,000	$ 2,289,509,000	2,725,635,000	[2]		$ 2,673,891,000
Accumulated Depreciation at December 31, 2016		692,608,000		640,434,000	611,408,000	$ 657,425,000			$ 692,608,000
Net Rentable Square Feet | ft²	[3]					10,379
Units						4,480			506
Loans Payable						$ 144,485,000			$ 414,546,000
Real estate, federal income tax basis						2,151,400,000
Properties under development or held for future development						40,232,000			36,094,000
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, beginning of period		2,673,891,000		2,547,188,000	2,289,509,000
Property acquisitions	[4]	240,499,000		162,702,000	289,140,000
Improvements	[4]	66,840,000		50,954,000	98,250,000
Impairment write-down		0		(5,909,000)	0
Write-off of disposed assets		(1,272,000)		(3,291,000)	(2,857,000)
Property sales		(254,323,000)		(77,753,000)	(126,854,000)
Balance, end of period		2,725,635,000	[2]	2,673,891,000	2,547,188,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, beginning of period		692,608,000		640,434,000	611,408,000
Depreciation		88,347,000		86,536,000	77,741,000
Write-off of disposed assets		(486,000)		(2,408,000)	(2,549,000)
Property sales		(123,044,000)		(31,954,000)	(46,166,000)
Balance, end of period		$ 657,425,000		$ 692,608,000	$ 640,434,000
Minimum [Member]
Real Estate and Accumulated Depreciation [Line Items]
Useful Life		3 years
Maximum [Member]
Real Estate and Accumulated Depreciation [Line Items]
Useful Life		50 years
Multifamily Properties [Member]
Real Estate and Accumulated Depreciation [Line Items]
Initial Cost, Land	[1]					179,981,000
Initial Cost, Buildings and Improvements	[1]					481,862,000
Net Improvements (Retirement) since Acquisition						259,254,000
Gross Amounts at Which Carried at December 31, 2016, Land						151,420,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						769,677,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 921,097,000				921,097,000
Accumulated Depreciation at December 31, 2016		167,157,000				$ 167,157,000
Net Rentable Square Feet | ft²	[3]					4,345
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	921,097,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 167,157,000
3801 Connecticut [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Washington, DC
Initial Cost, Land	[1]					$ 420,000
Initial Cost, Buildings and Improvements	[1]					2,678,000
Net Improvements (Retirement) since Acquisition						14,548,000
Gross Amounts at Which Carried at December 31, 2016, Land						420,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						17,226,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 17,646,000				17,646,000
Accumulated Depreciation at December 31, 2016		$ 10,671,000				$ 10,671,000
Year of Construction		Jan. 1, 1951
Date of Acquisition		Jan. 1, 1963
Net Rentable Square Feet | ft²	[3]					178
Units | unit						307
Depreciation Life	[5]	30 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 17,646,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 10,671,000
Roosevelt Towers [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Virginia
Initial Cost, Land	[1]					$ 336,000
Initial Cost, Buildings and Improvements	[1]					1,996,000
Net Improvements (Retirement) since Acquisition						12,261,000
Gross Amounts at Which Carried at December 31, 2016, Land						336,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						14,257,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 14,593,000				14,593,000
Accumulated Depreciation at December 31, 2016		$ 9,491,000				$ 9,491,000
Year of Construction		Jan. 1, 1964
Date of Acquisition		May 1, 1965
Net Rentable Square Feet | ft²	[3]					170
Units | unit						191
Depreciation Life	[5]	40 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 14,593,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 9,491,000
Park Adams [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Virginia
Initial Cost, Land	[1]					$ 287,000
Initial Cost, Buildings and Improvements	[1]					1,654,000
Net Improvements (Retirement) since Acquisition						11,904,000
Gross Amounts at Which Carried at December 31, 2016, Land						287,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						13,558,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 13,845,000				13,845,000
Accumulated Depreciation at December 31, 2016		$ 9,444,000				$ 9,444,000
Year of Construction		Jan. 1, 1959
Date of Acquisition		Jan. 1, 1969
Net Rentable Square Feet | ft²	[3]					173
Units | unit						200
Depreciation Life	[5]	35 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 13,845,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 9,444,000
The Ashby at McLean [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Virginia
Initial Cost, Land	[1]					$ 4,356,000
Initial Cost, Buildings and Improvements	[1]					17,102,000
Net Improvements (Retirement) since Acquisition						22,576,000
Gross Amounts at Which Carried at December 31, 2016, Land						4,356,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						39,678,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 44,034,000				44,034,000
Accumulated Depreciation at December 31, 2016		$ 23,631,000				$ 23,631,000
Year of Construction		Jan. 1, 1982
Date of Acquisition		Aug. 1, 1996
Net Rentable Square Feet | ft²	[3]					274
Units | unit						256
Depreciation Life	[5]	30 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 44,034,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 23,631,000
Walker House Apartments [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Maryland
Initial Cost, Land	[1]					$ 2,851,000
Initial Cost, Buildings and Improvements	[1]					7,946,000
Net Improvements (Retirement) since Acquisition						7,157,000
Gross Amounts at Which Carried at December 31, 2016, Land						2,851,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						15,103,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 17,954,000				17,954,000
Accumulated Depreciation at December 31, 2016		$ 10,751,000				$ 10,751,000
Year of Construction		Jan. 1, 1971
Date of Acquisition		Mar. 1, 1996
Net Rentable Square Feet | ft²	[3]					157
Units | unit						212
Depreciation Life	[5]	30 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 17,954,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 10,751,000
Bethesda Hill Apartments [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Maryland
Initial Cost, Land	[1]					$ 3,900,000
Initial Cost, Buildings and Improvements	[1]					13,412,000
Net Improvements (Retirement) since Acquisition						13,280,000
Gross Amounts at Which Carried at December 31, 2016, Land						3,900,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						26,692,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 30,592,000				30,592,000
Accumulated Depreciation at December 31, 2016		$ 17,788,000				$ 17,788,000
Year of Construction		Jan. 1, 1986
Date of Acquisition		Nov. 1, 1997
Net Rentable Square Feet | ft²	[3]					225
Units | unit						195
Depreciation Life	[5]	30 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 30,592,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 17,788,000
Bennett Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Virginia
Initial Cost, Land	[1]					$ 2,861,000
Initial Cost, Buildings and Improvements	[1]					917,000
Net Improvements (Retirement) since Acquisition						80,226,000
Gross Amounts at Which Carried at December 31, 2016, Land						4,774,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						79,230,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 84,004,000				84,004,000
Accumulated Depreciation at December 31, 2016		$ 31,960,000				$ 31,960,000
Year of Construction		Jan. 1, 2007
Date of Acquisition		Feb. 1, 2001
Net Rentable Square Feet | ft²	[3]					214
Units | unit						224
Depreciation Life	[5]	28 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 84,004,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 31,960,000
The Clayborne [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Virginia
Initial Cost, Land	[1]					$ 269,000
Initial Cost, Buildings and Improvements	[1]					0
Net Improvements (Retirement) since Acquisition						30,858,000
Gross Amounts at Which Carried at December 31, 2016, Land						699,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						30,428,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 31,127,000				31,127,000
Accumulated Depreciation at December 31, 2016		$ 13,831,000				$ 13,831,000
Year of Construction		Jan. 1, 2008
Date of Acquisition		Jun. 1, 2003
Net Rentable Square Feet | ft²	[3]					60
Units | unit						74
Depreciation Life	[5]	26 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 31,127,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 13,831,000
The Kenmore [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Washington, DC
Initial Cost, Land	[1],[6]					$ 28,222,000
Initial Cost, Buildings and Improvements	[1],[6]					33,955,000
Net Improvements (Retirement) since Acquisition	[6]					11,422,000
Gross Amounts at Which Carried at December 31, 2016, Land	[6]					28,222,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements	[6]					45,377,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2],[6]	$ 73,599,000				73,599,000
Accumulated Depreciation at December 31, 2016	[6]	$ 12,152,000				$ 12,152,000
Year of Construction		Jan. 1, 1948
Date of Acquisition	[6]	Sep. 1, 2008
Net Rentable Square Feet | ft²	[3]					268
Units | unit						374
Depreciation Life	[5]	30 years
Loans Payable						$ 32,900,000
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2],[6]	$ 73,599,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period	[6]	$ 12,152,000
The Maxwell [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Virginia
Initial Cost, Land	[1]					12,787,000
Initial Cost, Buildings and Improvements	[1]					0
Net Improvements (Retirement) since Acquisition	[7]					38,013,000
Gross Amounts at Which Carried at December 31, 2016, Land	[7]					12,851,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements	[7]					37,949,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2],[7]	$ 50,800,000				50,800,000
Accumulated Depreciation at December 31, 2016	[7]	$ 4,571,000				$ 4,571,000
Year of Construction		Jan. 1, 2014
Date of Acquisition	[7]	Jun. 1, 2011
Net Rentable Square Feet | ft²	[3]					139
Units | unit						163
Depreciation Life	[5]	30 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2],[7]	$ 50,800,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period	[7]	$ 4,571,000
The Paramount [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Virginia
Initial Cost, Land	[1]					$ 8,568,000
Initial Cost, Buildings and Improvements	[1]					38,716,000
Net Improvements (Retirement) since Acquisition						2,073,000
Gross Amounts at Which Carried at December 31, 2016, Land						8,568,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						40,789,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 49,357,000				49,357,000
Accumulated Depreciation at December 31, 2016		$ 5,774,000				$ 5,774,000
Year of Construction		Jan. 1, 1984
Date of Acquisition		Oct. 1, 2013
Net Rentable Square Feet | ft²	[3]					141
Units | unit						135
Depreciation Life	[5]	30 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 49,357,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 5,774,000
Yale West [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Washington, DC
Initial Cost, Land	[1],[6]					$ 14,684,000
Initial Cost, Buildings and Improvements	[1],[6]					62,069,000
Net Improvements (Retirement) since Acquisition	[6]					549,000
Gross Amounts at Which Carried at December 31, 2016, Land	[6]					14,684,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements	[6]					62,618,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2],[6]	$ 77,302,000				77,302,000
Accumulated Depreciation at December 31, 2016	[6]	$ 6,480,000				$ 6,480,000
Year of Construction		Jan. 1, 2011
Date of Acquisition	[6]	Feb. 1, 2014
Net Rentable Square Feet | ft²	[3]					238
Units | unit						216				216
Depreciation Life	[5]	30 years
Loans Payable	[8]					$ 47,078,000			47,502,000
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2],[6]	$ 77,302,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period	[6]	$ 6,480,000
The Wellington [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Virginia
Initial Cost, Land	[1]					30,548,000
Initial Cost, Buildings and Improvements	[1]					116,563,000
Net Improvements (Retirement) since Acquisition						4,137,000
Gross Amounts at Which Carried at December 31, 2016, Land						30,548,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						120,700,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 151,248,000				151,248,000
Accumulated Depreciation at December 31, 2016		$ 6,325,000				$ 6,325,000
Year of Construction		Jan. 1, 1960
Date of Acquisition		Jul. 1, 2015
Net Rentable Square Feet | ft²	[3]					842
Units | unit						711
Depreciation Life	[5]	30 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 151,248,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 6,325,000
The Wellington land parcel [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Virginia
Initial Cost, Land	[1],[9]					$ 15,000,000
Initial Cost, Buildings and Improvements	[1],[9]					0
Net Improvements (Retirement) since Acquisition	[9]					3,952,000
Gross Amounts at Which Carried at December 31, 2016, Land						0
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements	[9]					18,952,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2],[9]	$ 18,952,000				18,952,000
Accumulated Depreciation at December 31, 2016		$ 0				0
Date of Acquisition		Jul. 1, 2015
Properties under development or held for future development						19,000,000			19,000,000
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2],[9]	$ 18,952,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 0
Riverside Apartments [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Virginia
Initial Cost, Land	[1]					38,924,000
Initial Cost, Buildings and Improvements	[1]					184,854,000
Net Improvements (Retirement) since Acquisition						5,857,000
Gross Amounts at Which Carried at December 31, 2016, Land						38,924,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						190,711,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 229,635,000				229,635,000
Accumulated Depreciation at December 31, 2016		$ 4,288,000				$ 4,288,000
Year of Construction		Jan. 1, 1971
Date of Acquisition		May 20, 2016
Net Rentable Square Feet | ft²	[3]					1,266
Units | unit						1,222		1,222
Depreciation Life	[5]	30 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 229,635,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 4,288,000
Riverside Apartments land parcel [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Virginia
Initial Cost, Land	[1],[9]					$ 15,968,000
Initial Cost, Buildings and Improvements	[1]					0
Net Improvements (Retirement) since Acquisition	[9]					441,000
Gross Amounts at Which Carried at December 31, 2016, Land						0
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements	[9]					16,409,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2],[9]	$ 16,409,000				16,409,000
Accumulated Depreciation at December 31, 2016		$ 0				0
Date of Acquisition		May 20, 2016
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2],[9]	$ 16,409,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		0
Office Buildings [Member]
Real Estate and Accumulated Depreciation [Line Items]
Initial Cost, Land	[1]					301,223,000
Initial Cost, Buildings and Improvements	[1]					778,356,000
Net Improvements (Retirement) since Acquisition						272,439,000
Gross Amounts at Which Carried at December 31, 2016, Land						301,224,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						1,050,794,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	1,352,018,000				1,352,018,000
Accumulated Depreciation at December 31, 2016		363,646,000				$ 363,646,000
Net Rentable Square Feet | ft²	[3]					3,704
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	1,352,018,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 363,646,000
515 King Street [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Virginia
Initial Cost, Land	[1]					$ 4,102,000
Initial Cost, Buildings and Improvements	[1]					3,931,000
Net Improvements (Retirement) since Acquisition						7,795,000
Gross Amounts at Which Carried at December 31, 2016, Land						4,102,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						11,726,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 15,828,000				15,828,000
Accumulated Depreciation at December 31, 2016		$ 5,775,000				$ 5,775,000
Year of Construction		Jan. 1, 1966
Date of Acquisition		Jul. 1, 1992
Net Rentable Square Feet | ft²						75
Depreciation Life	[5]	50 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 15,828,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 5,775,000
1220 19th Street [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Washington, DC
Initial Cost, Land	[1]					$ 7,803,000
Initial Cost, Buildings and Improvements	[1]					11,366,000
Net Improvements (Retirement) since Acquisition						15,973,000
Gross Amounts at Which Carried at December 31, 2016, Land						7,802,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						27,340,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 35,142,000				35,142,000
Accumulated Depreciation at December 31, 2016		$ 15,403,000				$ 15,403,000
Year of Construction		Jan. 1, 1976
Date of Acquisition		Nov. 1, 1995
Net Rentable Square Feet | ft²						103
Depreciation Life	[5]	30 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 35,142,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 15,403,000
1600 Wilson Boulevard [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Virginia
Initial Cost, Land	[1]					$ 6,661,000
Initial Cost, Buildings and Improvements	[1]					16,742,000
Net Improvements (Retirement) since Acquisition						27,930,000
Gross Amounts at Which Carried at December 31, 2016, Land						6,661,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						44,672,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 51,333,000				51,333,000
Accumulated Depreciation at December 31, 2016		$ 22,661,000				$ 22,661,000
Year of Construction		Jan. 1, 1973
Date of Acquisition		Oct. 1, 1997
Net Rentable Square Feet | ft²						169
Depreciation Life	[5]	30 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 51,333,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 22,661,000
Silverline Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Virginia
Initial Cost, Land	[1]					$ 12,049,000
Initial Cost, Buildings and Improvements	[1]					71,825,000
Net Improvements (Retirement) since Acquisition						98,303,000
Gross Amounts at Which Carried at December 31, 2016, Land						12,049,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						170,128,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 182,177,000				182,177,000
Accumulated Depreciation at December 31, 2016		$ 77,829,000				$ 77,829,000
Year of Construction		Jan. 1, 1972
Date of Acquisition		Nov. 1, 1997
Net Rentable Square Feet | ft²						546
Depreciation Life	[5]	30 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 182,177,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 77,829,000
Courthouse Square [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Virginia
Initial Cost, Land	[1]					$ 0
Initial Cost, Buildings and Improvements	[1]					17,096,000
Net Improvements (Retirement) since Acquisition						9,369,000
Gross Amounts at Which Carried at December 31, 2016, Land						0
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						26,465,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 26,465,000				26,465,000
Accumulated Depreciation at December 31, 2016		$ 14,252,000				$ 14,252,000
Year of Construction		Jan. 1, 1979
Date of Acquisition		Oct. 1, 2000
Net Rentable Square Feet | ft²						118
Depreciation Life	[5]	30 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 26,465,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 14,252,000
1776 G Street [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Washington, DC
Initial Cost, Land	[1]					$ 31,500,000
Initial Cost, Buildings and Improvements	[1]					54,327,000
Net Improvements (Retirement) since Acquisition						7,448,000
Gross Amounts at Which Carried at December 31, 2016, Land						31,500,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						61,775,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 93,275,000				93,275,000
Accumulated Depreciation at December 31, 2016		$ 29,983,000				$ 29,983,000
Year of Construction		Jan. 1, 1979
Date of Acquisition		Aug. 1, 2003
Net Rentable Square Feet | ft²						265
Depreciation Life	[5]	30 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 93,275,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 29,983,000
Monument II [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Virginia
Initial Cost, Land	[1]					$ 10,244,000
Initial Cost, Buildings and Improvements	[1]					65,205,000
Net Improvements (Retirement) since Acquisition						9,115,000
Gross Amounts at Which Carried at December 31, 2016, Land						10,244,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						74,320,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 84,564,000				84,564,000
Accumulated Depreciation at December 31, 2016		$ 25,520,000				$ 25,520,000
Year of Construction		Jan. 1, 2000
Date of Acquisition		Mar. 1, 2007
Net Rentable Square Feet | ft²						208
Depreciation Life	[5]	30 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 84,564,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 25,520,000
2000 M Street [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Washington, DC
Initial Cost, Land	[1]					$ 0
Initial Cost, Buildings and Improvements	[1]					61,101,000
Net Improvements (Retirement) since Acquisition						21,696,000
Gross Amounts at Which Carried at December 31, 2016, Land						0
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						82,797,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 82,797,000				82,797,000
Accumulated Depreciation at December 31, 2016		$ 27,776,000				$ 27,776,000
Year of Construction		Jan. 1, 1971
Date of Acquisition		Dec. 1, 2007
Net Rentable Square Feet | ft²						231
Depreciation Life	[5]	30 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 82,797,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 27,776,000
M Street 2445 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Washington, DC
Initial Cost, Land	[1]					$ 46,887,000
Initial Cost, Buildings and Improvements	[1]					106,743,000
Net Improvements (Retirement) since Acquisition						6,210,000
Gross Amounts at Which Carried at December 31, 2016, Land						46,887,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						112,953,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 159,840,000				159,840,000
Accumulated Depreciation at December 31, 2016		$ 36,583,000				$ 36,583,000
Year of Construction		Jan. 1, 1986
Date of Acquisition		Dec. 1, 2008
Net Rentable Square Feet | ft²						290
Depreciation Life	[5]	30 years
Loans Payable	[10]					$ 0			101,866,000
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 159,840,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 36,583,000
925 Corporate Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Virginia
Initial Cost, Land	[1]					4,518,000
Initial Cost, Buildings and Improvements	[1]					24,801,000
Net Improvements (Retirement) since Acquisition						1,080,000
Gross Amounts at Which Carried at December 31, 2016, Land						4,518,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						25,881,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 30,399,000				30,399,000
Accumulated Depreciation at December 31, 2016		$ 8,538,000				$ 8,538,000
Year of Construction		Jan. 1, 2007
Date of Acquisition		Jun. 1, 2010
Net Rentable Square Feet | ft²						134
Depreciation Life	[5]	30 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 30,399,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 8,538,000
1000 Corporate Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Virginia
Initial Cost, Land	[1]					$ 4,897,000
Initial Cost, Buildings and Improvements	[1]					25,376,000
Net Improvements (Retirement) since Acquisition						(249,000)
Gross Amounts at Which Carried at December 31, 2016, Land						4,898,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						25,126,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 30,024,000				30,024,000
Accumulated Depreciation at December 31, 2016		$ 7,867,000				$ 7,867,000
Year of Construction		Jan. 1, 2009
Date of Acquisition		Jun. 1, 2010
Net Rentable Square Feet | ft²						136
Depreciation Life	[5]	30 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 30,024,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 7,867,000
1140 Connecticut Avenue [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Washington, DC
Initial Cost, Land	[1]					$ 25,226,000
Initial Cost, Buildings and Improvements	[1]					50,495,000
Net Improvements (Retirement) since Acquisition						13,123,000
Gross Amounts at Which Carried at December 31, 2016, Land						25,226,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						63,618,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 88,844,000				88,844,000
Accumulated Depreciation at December 31, 2016		$ 16,015,000				$ 16,015,000
Year of Construction		Jan. 1, 1966
Date of Acquisition		Jan. 1, 2011
Net Rentable Square Feet | ft²						183
Depreciation Life	[5]	30 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 88,844,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 16,015,000
1227 25th Street [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Washington, DC
Initial Cost, Land	[1]					$ 17,505,000
Initial Cost, Buildings and Improvements	[1]					21,319,000
Net Improvements (Retirement) since Acquisition						4,507,000
Gross Amounts at Which Carried at December 31, 2016, Land						17,505,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						25,826,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 43,331,000				43,331,000
Accumulated Depreciation at December 31, 2016		$ 6,998,000				$ 6,998,000
Year of Construction		Jan. 1, 1988
Date of Acquisition		Mar. 1, 2011
Net Rentable Square Feet | ft²						136
Depreciation Life	[5]	30 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 43,331,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 6,998,000
Braddock Place Member
Real Estate and Accumulated Depreciation [Line Items]
Location		Virginia
Initial Cost, Land	[1]					$ 18,817,000
Initial Cost, Buildings and Improvements	[1]					71,250,000
Net Improvements (Retirement) since Acquisition						10,978,000
Gross Amounts at Which Carried at December 31, 2016, Land						18,818,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						82,227,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 101,045,000				101,045,000
Accumulated Depreciation at December 31, 2016		$ 20,104,000				$ 20,104,000
Year of Construction		Jan. 1, 1985
Date of Acquisition		Sep. 1, 2011
Net Rentable Square Feet | ft²						348
Depreciation Life	[5]	30 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 101,045,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 20,104,000
John Marshall II Member
Real Estate and Accumulated Depreciation [Line Items]
Location		Virginia
Initial Cost, Land	[1]					$ 13,490,000
Initial Cost, Buildings and Improvements	[1]					53,024,000
Net Improvements (Retirement) since Acquisition						2,841,000
Gross Amounts at Which Carried at December 31, 2016, Land						13,490,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						55,865,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 69,355,000				69,355,000
Accumulated Depreciation at December 31, 2016		$ 11,536,000				$ 11,536,000
Year of Construction		Jan. 1, 1996
Date of Acquisition		Sep. 1, 2011
Net Rentable Square Feet | ft²						223
Depreciation Life	[5]	30 years
Loans Payable	[11]					$ 0			51,011,000
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 69,355,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 11,536,000
Fairgate at Ballston [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Virginia
Initial Cost, Land	[1]					17,750,000
Initial Cost, Buildings and Improvements	[1]					29,885,000
Net Improvements (Retirement) since Acquisition						5,327,000
Gross Amounts at Which Carried at December 31, 2016, Land						17,750,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						35,212,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 52,962,000				52,962,000
Accumulated Depreciation at December 31, 2016		$ 7,288,000				$ 7,288,000
Year of Construction		Jan. 1, 1988
Date of Acquisition		Jun. 1, 2012
Net Rentable Square Feet | ft²						143
Depreciation Life	[5]	30 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 52,962,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 7,288,000
The Army Navy Club Building [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Washington, DC
Initial Cost, Land	[1],[6]					$ 30,796,000
Initial Cost, Buildings and Improvements	[1],[6],[7]					39,315,000
Net Improvements (Retirement) since Acquisition	[6],[7]					4,885,000
Gross Amounts at Which Carried at December 31, 2016, Land	[6]					30,796,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements	[6],[7]					44,200,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2],[6],[7]	$ 74,996,000				74,996,000
Accumulated Depreciation at December 31, 2016	[6]	$ 5,633,000				$ 5,633,000
Year of Construction		Jan. 1, 1912
Date of Acquisition		Mar. 1, 2014
Net Rentable Square Feet | ft²						108
Depreciation Life	[5]	30 years
Loans Payable	[12]					$ 49,618,000			50,750,000
Properties under development or held for future development						2,200,000
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2],[6],[7]	$ 74,996,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period	[6]	$ 5,633,000
1775 Eye Street [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Washington, DC
Initial Cost, Land	[1]					48,086,000
Initial Cost, Buildings and Improvements	[1]					51,074,000
Net Improvements (Retirement) since Acquisition						7,833,000
Gross Amounts at Which Carried at December 31, 2016, Land						48,086,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						58,907,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 106,993,000				106,993,000
Accumulated Depreciation at December 31, 2016		$ 7,593,000				$ 7,593,000
Year of Construction		Jan. 1, 1964
Date of Acquisition		May 1, 2014
Net Rentable Square Feet | ft²						186
Depreciation Life	[5]	30 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 106,993,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 7,593,000
1901 Pennsylvania Avenue [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Washington, DC
Initial Cost, Land	[1]					$ 892,000
Initial Cost, Buildings and Improvements	[1]					3,481,000
Net Improvements (Retirement) since Acquisition						18,275,000
Gross Amounts at Which Carried at December 31, 2016, Land						892,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						21,756,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 22,648,000				22,648,000
Accumulated Depreciation at December 31, 2016		$ 16,292,000				$ 16,292,000
Year of Construction		Jan. 1, 1960
Date of Acquisition		May 1, 1977
Net Rentable Square Feet | ft²						102
Depreciation Life	[5]	28 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 22,648,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		16,292,000
Retail Centers [Member]
Real Estate and Accumulated Depreciation [Line Items]
Initial Cost, Land	[1]					$ 120,969,000
Initial Cost, Buildings and Improvements	[1]					249,498,000
Net Improvements (Retirement) since Acquisition						82,053,000
Gross Amounts at Which Carried at December 31, 2016, Land						120,671,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						331,849,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	452,520,000				452,520,000
Accumulated Depreciation at December 31, 2016		126,622,000				$ 126,622,000
Net Rentable Square Feet | ft²						2,330
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	452,520,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 126,622,000
Takoma Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Maryland
Initial Cost, Land	[1]					$ 415,000
Initial Cost, Buildings and Improvements	[1]					1,084,000
Net Improvements (Retirement) since Acquisition						332,000
Gross Amounts at Which Carried at December 31, 2016, Land						415,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						1,416,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 1,831,000				1,831,000
Accumulated Depreciation at December 31, 2016		$ 1,194,000				$ 1,194,000
Year of Construction		Jan. 1, 1962
Date of Acquisition		Jul. 1, 1963
Net Rentable Square Feet | ft²						51
Depreciation Life	[5]	50 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 1,831,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 1,194,000
Westminster [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Maryland
Initial Cost, Land	[1]					$ 519,000
Initial Cost, Buildings and Improvements	[1]					1,775,000
Net Improvements (Retirement) since Acquisition						9,839,000
Gross Amounts at Which Carried at December 31, 2016, Land						519,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						11,614,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 12,133,000				12,133,000
Accumulated Depreciation at December 31, 2016		$ 7,614,000				$ 7,614,000
Year of Construction		Jan. 1, 1969
Date of Acquisition		Sep. 1, 1972
Net Rentable Square Feet | ft²						150
Depreciation Life	[5]	37 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 12,133,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 7,614,000
Concord Centre [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Virginia
Initial Cost, Land	[1]					$ 413,000
Initial Cost, Buildings and Improvements	[1]					850,000
Net Improvements (Retirement) since Acquisition						5,845,000
Gross Amounts at Which Carried at December 31, 2016, Land						413,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						6,695,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 7,108,000				7,108,000
Accumulated Depreciation at December 31, 2016		$ 3,414,000				$ 3,414,000
Year of Construction		Jan. 1, 1960
Date of Acquisition		Dec. 1, 1973
Net Rentable Square Feet | ft²						76
Depreciation Life	[5]	33 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 7,108,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 3,414,000
Wheaton Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Maryland
Initial Cost, Land	[1]					$ 796,000
Initial Cost, Buildings and Improvements	[1]					857,000
Net Improvements (Retirement) since Acquisition						4,740,000
Gross Amounts at Which Carried at December 31, 2016, Land						796,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						5,597,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 6,393,000				6,393,000
Accumulated Depreciation at December 31, 2016		$ 3,931,000				$ 3,931,000
Year of Construction		Jan. 1, 1967
Date of Acquisition		Sep. 1, 1977
Net Rentable Square Feet | ft²						74
Depreciation Life	[5]	50 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 6,393,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 3,931,000
Bradlee [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Virginia
Initial Cost, Land	[1]					$ 4,152,000
Initial Cost, Buildings and Improvements	[1]					5,383,000
Net Improvements (Retirement) since Acquisition						14,205,000
Gross Amounts at Which Carried at December 31, 2016, Land						4,152,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						19,588,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 23,740,000				23,740,000
Accumulated Depreciation at December 31, 2016		$ 11,579,000				$ 11,579,000
Year of Construction		Jan. 1, 1955
Date of Acquisition		Dec. 1, 1984
Net Rentable Square Feet | ft²						172
Depreciation Life	[5]	40 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 23,740,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 11,579,000
Chevy Chase Metro Plaza [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Washington, DC
Initial Cost, Land	[1]					$ 1,549,000
Initial Cost, Buildings and Improvements	[1]					4,304,000
Net Improvements (Retirement) since Acquisition						8,245,000
Gross Amounts at Which Carried at December 31, 2016, Land						1,549,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						12,549,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 14,098,000				14,098,000
Accumulated Depreciation at December 31, 2016		$ 6,908,000				$ 6,908,000
Year of Construction		Jan. 1, 1975
Date of Acquisition		Sep. 1, 1985
Net Rentable Square Feet | ft²						50
Depreciation Life	[5]	50 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 14,098,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 6,908,000
Shoppes of Foxchase [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Virginia
Initial Cost, Land	[1]					$ 5,838,000
Initial Cost, Buildings and Improvements	[1]					2,979,000
Net Improvements (Retirement) since Acquisition						14,868,000
Gross Amounts at Which Carried at December 31, 2016, Land						5,838,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						17,847,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 23,685,000				23,685,000
Accumulated Depreciation at December 31, 2016		$ 7,298,000				$ 7,298,000
Year of Construction		Jan. 1, 1960
Date of Acquisition		Jun. 1, 1994
Net Rentable Square Feet | ft²						134
Depreciation Life	[5]	50 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 23,685,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 7,298,000
Frederick County Square [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Maryland
Initial Cost, Land	[1]					$ 6,561,000
Initial Cost, Buildings and Improvements	[1]					6,830,000
Net Improvements (Retirement) since Acquisition						5,295,000
Gross Amounts at Which Carried at December 31, 2016, Land						6,561,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						12,125,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 18,686,000				18,686,000
Accumulated Depreciation at December 31, 2016		$ 7,828,000				$ 7,828,000
Year of Construction		Jan. 1, 1973
Date of Acquisition		Aug. 1, 1995
Net Rentable Square Feet | ft²						227
Depreciation Life	[5]	30 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 18,686,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 7,828,000
800 S. Washington Street [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Virginia
Initial Cost, Land	[1]					$ 2,904,000
Initial Cost, Buildings and Improvements	[1]					5,489,000
Net Improvements (Retirement) since Acquisition						5,954,000
Gross Amounts at Which Carried at December 31, 2016, Land						2,904,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						11,443,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 14,347,000				14,347,000
Accumulated Depreciation at December 31, 2016		$ 5,123,000				$ 5,123,000
Year of Construction		Jan. 1, 1951
Date of Acquisition		Jun. 1, 1998
Net Rentable Square Feet | ft²						46
Depreciation Life	[5]	30 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 14,347,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 5,123,000
Centre at Hagerstown . [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Maryland
Initial Cost, Land	[1]					$ 13,029,000
Initial Cost, Buildings and Improvements	[1]					25,415,000
Net Improvements (Retirement) since Acquisition						2,610,000
Gross Amounts at Which Carried at December 31, 2016, Land						13,029,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						28,025,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 41,054,000				41,054,000
Accumulated Depreciation at December 31, 2016		$ 13,856,000				$ 13,856,000
Year of Construction		Jan. 1, 2000
Date of Acquisition		Jun. 1, 2002
Net Rentable Square Feet | ft²						331
Depreciation Life	[5]	30 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 41,054,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 13,856,000
Frederick Crossing [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Maryland
Initial Cost, Land	[1]					$ 12,759,000
Initial Cost, Buildings and Improvements	[1]					35,477,000
Net Improvements (Retirement) since Acquisition						2,265,000
Gross Amounts at Which Carried at December 31, 2016, Land						12,759,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						37,742,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 50,501,000				50,501,000
Accumulated Depreciation at December 31, 2016		$ 15,769,000				$ 15,769,000
Year of Construction		Jan. 1, 1999
Date of Acquisition		Mar. 1, 2005
Net Rentable Square Feet | ft²						295
Depreciation Life	[5]	30 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 50,501,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 15,769,000
Randolph Shopping Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Maryland
Initial Cost, Land	[1]					$ 4,928,000
Initial Cost, Buildings and Improvements	[1]					13,025,000
Net Improvements (Retirement) since Acquisition						1,154,000
Gross Amounts at Which Carried at December 31, 2016, Land						4,928,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						14,179,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 19,107,000				19,107,000
Accumulated Depreciation at December 31, 2016		$ 5,288,000				$ 5,288,000
Year of Construction		Jan. 1, 1972
Date of Acquisition		May 1, 2006
Net Rentable Square Feet | ft²						82
Depreciation Life	[5]	30 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 19,107,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 5,288,000
Montrose Shopping Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Maryland
Initial Cost, Land	[1]					$ 11,612,000
Initial Cost, Buildings and Improvements	[1]					22,410,000
Net Improvements (Retirement) since Acquisition						2,196,000
Gross Amounts at Which Carried at December 31, 2016, Land						11,020,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						25,198,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 36,218,000				36,218,000
Accumulated Depreciation at December 31, 2016		$ 9,289,000				$ 9,289,000
Year of Construction		Jan. 1, 1970
Date of Acquisition		May 1, 2006
Net Rentable Square Feet | ft²						145
Depreciation Life	[5]	30 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 36,218,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 9,289,000
Gateway Overlook [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Maryland
Initial Cost, Land	[1]					$ 28,816,000
Initial Cost, Buildings and Improvements	[1]					52,249,000
Net Improvements (Retirement) since Acquisition						622,000
Gross Amounts at Which Carried at December 31, 2016, Land						29,110,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements						52,577,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2]	$ 81,687,000				81,687,000
Accumulated Depreciation at December 31, 2016		$ 16,408,000				$ 16,408,000
Year of Construction		Jan. 1, 2007
Date of Acquisition		Dec. 1, 2010
Net Rentable Square Feet | ft²						220
Depreciation Life	[5]	30 years
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2]	$ 81,687,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 16,408,000
Olney Village Center Member
Real Estate and Accumulated Depreciation [Line Items]
Location		Maryland
Initial Cost, Land	[1],[6]					$ 15,842,000
Initial Cost, Buildings and Improvements	[1],[6]					39,133,000
Net Improvements (Retirement) since Acquisition	[6]					1,970,000
Gross Amounts at Which Carried at December 31, 2016, Land	[6]					15,842,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements	[6]					41,103,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2],[6]	$ 56,945,000				56,945,000
Accumulated Depreciation at December 31, 2016		$ 8,252,000				$ 8,252,000
Year of Construction		Jan. 1, 1979
Date of Acquisition	[6]	Aug. 1, 2011
Net Rentable Square Feet | ft²						199
Depreciation Life	[5]	30 years
Loans Payable						$ 14,851,000			16,503,000
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2],[6]	$ 56,945,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 8,252,000
Spring Vally Retail Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Location		Washington, DC
Initial Cost, Land	[1]					10,836,000
Initial Cost, Buildings and Improvements	[1]					32,238,000
Net Improvements (Retirement) since Acquisition	[7]					1,913,000
Gross Amounts at Which Carried at December 31, 2016, Land						10,836,000
Gross Amounts at Which Carried at December 31, 2016, Buildings and Improvements	[7]					34,151,000
Gross Amounts at Which Carried at December 31, 2016, Total	[2],[7]	$ 44,987,000				44,987,000
Accumulated Depreciation at December 31, 2016		$ 2,871,000				$ 2,871,000
Year of Construction		Jan. 1, 1941
Date of Acquisition		Oct. 1, 2014
Net Rentable Square Feet | ft²						78
Depreciation Life	[5]	30 years
Properties under development or held for future development						$ 1,100,000
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, end of period	[2],[7]	$ 44,987,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, end of period		$ 2,871,000
Riverside Developments [Member]
Real Estate and Accumulated Depreciation [Line Items]
Properties under development or held for future development						16,400,000			$ 16,400,000
Army Navy Building and Spring Valley Village [Member]
Real Estate and Accumulated Depreciation [Line Items]
Properties under development or held for future development						$ 4,800,000
[1]	The purchase cost of real estate investments has been divided between land and buildings and improvements on the basis of management’s determination of the fair values.
[2]	At December 31, 2016, total land, buildings and improvements are carried at $2,151.4 million for federal income tax purposes.
[3]	Residential properties are presented in gross square feet.
[4]	Includes non-cash accruals for capital items and assumed mortgages.
[5]	The useful life shown is for the main structure. Buildings and improvements are depreciated over various useful lives ranging from 3 to 50 years.
[6]	At December 31, 2016, our properties were encumbered by non-recourse mortgage amounts as follows: $32.9 million on The Kenmore, $14.9 million on Olney Village Center, $47.1 million on Yale West, and $49.6 million on The Amy Navy Building (prepaid at par in February 2017). Mortgage amounts exclude premiums and debt loan costs.
[7]	As of December 31, 2016, Washington REIT had investments in various development and redevelopment projects, including Army Navy Building and Spring Valley Village. The total value of these various projects not yet placed in service is $4.8 million at December 31, 2016.
[8]	The maturity date of the mortgage note is January 1, 2052, but can be prepaid, without penalty, beginning on January 31, 2022.
[9]	As of December 31, 2016, Washington REIT had under development multifamily properties, the Wellington land parcel (Trove) and Riverside Apartments land parcel. The value not yet placed into service at December 31, 2016 was $19.0 million and $16.4 million, respectively.
[10]	Interest only was payable monthly until the note was prepaid without penalty in October 2016.
[11]	The note was prepaid without penalty in February 2016.
[12]	The note was prepaid without penalty in February 2017.