Elme Communities (ELME) 10-K 16 Feb 21 2020 FY Annual report Financial data

Cover

Cover - USD ($)	12 Months Ended
	Dec. 31, 2020	Feb. 11, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-06622
Entity Registrant Name	WASHINGTON REAL ESTATE INVESTMENT TRUST
Entity Central Index Key	0000104894
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Incorporation, State or Country Code	MD
Entity Tax Identification Number	53-0261100
Entity Address, Address Line One	1775 EYE STREET, NW
Entity Address, Address Line Two	SUITE 1000
Entity Address, City or Town	WASHINGTON
Entity Address, State or Province	DC
Entity Address, Postal Zip Code	20006
City Area Code	202
Local Phone Number	774-3200
Title of 12(b) Security	Shares of Beneficial Interest
Trading Symbol	WRE
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 1,811,606,216
Entity Common Stock, Shares Outstanding		84,559,065
Documents Incorporated by Reference	Portions of our definitive Proxy Statement relating to the 2021 Annual Meeting of Shareholders, to be filed with the Securities and Exchange Commission, are incorporated by reference in Part III, Items 10-14 of this Annual Report on Form 10-K as indicated herein.

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Assets
Land	$ 551,578	$ 566,807
Income producing property	2,432,039	2,392,415
Income producing property, at cost	2,983,617	2,959,222
Accumulated depreciation and amortization	(749,014)	(693,610)
Net income producing property	2,234,603	2,265,612
Properties under development or held for future development	37,615	124,193
Total real estate held for investment, net	2,272,218	2,389,805
Investment in real estate held for sale, net	0	57,028
Cash and cash equivalents	7,700	12,939
Restricted cash	603	1,812
Rents and other receivables	58,257	65,259
Prepaid expenses and other assets	71,040	95,149
Other assets related to properties sold or held for sale	0	6,336
Total assets	2,409,818	2,628,328
Liabilities
Notes payable, net	945,370	996,722
Mortgage notes payable, net	0	47,074
Line of credit	42,000	56,000
Accounts payable and other liabilities	58,773	71,136
Dividend payable	25,361	24,668
Advance rents	7,215	9,353
Tenant security deposits	9,990	10,595
Other liabilities related to properties sold or held for sale	0	718
Total liabilities	1,088,709	1,216,266
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; 84,409 and 82,099 shares issued and outstanding, as of December 31, 2020 and December 31, 2019, respectively	844	821
Additional paid in capital	1,649,366	1,592,487
Distributions in excess of net income	(298,860)	(183,405)
Accumulated other comprehensive (loss) income	(30,563)	1,823
Total shareholders’ equity	1,320,787	1,411,726
Noncontrolling interests in subsidiaries	322	336
Total equity	1,321,109	1,412,062
Total liabilities and equity	$ 2,409,818	$ 2,628,328

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Preferred shares, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred shares, authorized (in shares)	10,000,000	10,000,000
Preferred shares, issued (in shares)	0	0
Preferred shares, outstanding (in shares)	0	0
Shares of beneficial interest, par value (in dollars per share)	$ 0.01	$ 0.01
Shares of beneficial interest, authorized (in shares)	100,000,000	100,000,000
Shares of beneficial interest, issued (in shares)	84,409,000	82,099,000
Shares of beneficial interest, outstanding (in shares)	84,409,000	82,099,000

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue
Real estate rental revenue	$ 294,118	$ 309,180	$ 291,730
Expenses
Real estate expenses	112,909	115,580	105,592
Depreciation and amortization	120,030	136,253	111,826
Real estate impairment	0	8,374	1,886
General and administrative expenses	23,951	26,068	22,089
Total expenses	256,890	286,275	241,393
Other operating income
(Loss) gain on sale of real estate	(15,009)	59,961	2,495
Real estate operating income	22,219	82,866	52,832
Other income (expense)
Interest expense	(37,305)	(53,734)	(50,501)
Loss on interest rate derivatives	(560)	0	0
Loss on extinguishment of debt	(34)	0	(1,178)
Total other income (expense)	(37,899)	(53,734)	(51,679)
(Loss) income from continuing operations	(15,680)	29,132	1,153
Discontinued operations:
Income from operations of properties sold or held for sale	0	16,158	24,477
Gain on sale of real estate	0	339,024	0
Loss on extinguishment of debt	0	(764)	0
Income from discontinued operations	0	354,418	24,477
Net (loss) income	$ (15,680)	$ 383,550	$ 25,630
Basic net (loss) income per share
Continuing operations, basic (in dollars per share)	$ (0.20)	$ 0.36	$ 0.01
Discontinued operations, including gain on sale of real estate, basic (in dollars per share)	0	4.39	0.31
Basic net (loss) income per share (in dollars per share)	(0.20)	4.75	0.32
Diluted net (loss) income per share
Continuing operations, diluted (in dollars per share)	(0.20)	0.36	0.01
Discontinued operations, including gain on sale of real estate, diluted (in dollars per share)	0	4.39	0.31
Diluted net (loss) income per share (in dollars per share)	$ (0.20)	$ 4.75	$ 0.32
Weighted average shares outstanding – basic (in shares)	82,348	80,257	78,960
Weighted average shares outstanding – diluted (in shares)	82,348	80,335	79,042
Revenue, type	us-gaap:RealEstateMember	us-gaap:RealEstateMember	us-gaap:RealEstateMember
Expenses, type	us-gaap:RealEstateMember	us-gaap:RealEstateMember	us-gaap:RealEstateMember

Consolidated Statements of Comp

Consolidated Statements of Comprehensive (Loss) Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net (loss) income	$ (15,680)	$ 383,550	$ 25,630
Unrealized (loss) gain on interest rate derivatives	(33,025)	(8,016)	420
Reclassification of unrealized loss on interest rate derivatives to earnings	639	0	0
Comprehensive income attributable to the controlling interests	$ (48,066)	$ 375,534	$ 26,050

Consolidated Statements of Equi

Consolidated Statements of Equity - USD ($) shares in Thousands, $ in Thousands	Total	Cumulative effect of change in accounting principle	Total Shareholders’ Equity	Total Shareholders’ EquityCumulative effect of change in accounting principle	Shares of Beneficial Interest at Par Value	Additional Paid in Capital	Distributions in Excess of Net Income	Distributions in Excess of Net IncomeCumulative effect of change in accounting principle	Accumulated Other Comprehensive Income (Loss)	Non- controlling Interests in Subsidiary
Balance (in shares) at Dec. 31, 2017					78,510
Balance at Dec. 31, 2017	$ 1,095,336		$ 1,094,971		$ 785	$ 1,483,980	$ (399,213)		$ 9,419	$ 365
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	25,630		25,630				25,630
Unrealized (loss) gain on interest rate derivatives	420		420						420
Amortization of swap settlements	0
Distributions to noncontrolling interests	(14)									(14)
Dividends ($1.20 per common share)	$ (95,502)		(95,502)				(95,502)
Equity offerings, net of issuance costs (in shares)	1,165				1,165
Equity offerings, net of issuance costs	$ 35,472		35,472		$ 11	35,461
Shares issued under Dividend Reinvestment Program (in shares)	81				81
Shares issued under Dividend Reinvestment Program	$ 1,973		1,973		$ 1	1,972
Share grants, net of forfeitures and tax withholdings (in shares)					154
Share grants, net of forfeitures and tax withholdings	5,163		5,163		$ 2	5,161
Balance (in shares) at Dec. 31, 2018					79,910
Balance at Dec. 31, 2018	1,068,478	$ (906)	1,068,127	$ (906)	$ 799	1,526,574	(469,085)	$ (906)	9,839	351
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	383,550		383,550				383,550
Unrealized (loss) gain on interest rate derivatives	(8,016)		(8,016)						(8,016)
Amortization of swap settlements	0
Distributions to noncontrolling interests	(15)									(15)
Dividends ($1.20 per common share)	$ (96,964)		(96,964)				(96,964)
Equity offerings, net of issuance costs (in shares)	1,859				1,859
Equity offerings, net of issuance costs	$ 54,916		54,916		$ 18	54,898
Shares issued under Dividend Reinvestment Program (in shares)	173				173
Shares issued under Dividend Reinvestment Program	$ 4,755		4,755		$ 2	4,753
Share grants, net of forfeitures and tax withholdings (in shares)					157
Share grants, net of forfeitures and tax withholdings	6,264		6,264		$ 2	6,262
Balance (in shares) at Dec. 31, 2019					82,099
Balance at Dec. 31, 2019	1,412,062		1,411,726		$ 821	1,592,487	(183,405)		1,823	336
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	(15,680)		(15,680)				(15,680)
Unrealized (loss) gain on interest rate derivatives	(33,025)		(33,025)						(33,025)
Loss on interest rate derivatives	560		560						560
Amortization of swap settlements	79		79
Distributions to noncontrolling interests	(14)									(14)
Dividends ($1.20 per common share)	$ (99,775)		(99,775)				(99,775)
Equity offerings, net of issuance costs (in shares)	2,000				2,046
Equity offerings, net of issuance costs	$ 48,355		48,355		$ 20	48,335
Shares issued under Dividend Reinvestment Program (in shares)	89				90
Shares issued under Dividend Reinvestment Program	$ 2,121		2,121		$ 1	2,120
Share grants, net of forfeitures and tax withholdings (in shares)					174
Share grants, net of forfeitures and tax withholdings	6,426		6,426		$ 2	6,424
Balance (in shares) at Dec. 31, 2020					84,409
Balance at Dec. 31, 2020	$ 1,321,109		$ 1,320,787		$ 844	$ 1,649,366	$ (298,860)		$ (30,563)	$ 322

Consolidated Statements of Eq_2

Consolidated Statements of Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Stockholders' Equity [Abstract]
Dividends per common share (in dollars per share)	$ 1.20	$ 1.20	$ 1.20

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities
Net (loss) income	$ (15,680)	$ 383,550	$ 25,630
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Depreciation and amortization	120,030	141,179	121,228
Credit losses (gains) on lease related receivables	5,422	(10)	2,136
Real estate impairment	0	8,374	1,886
Loss (gain) on sale of real estate	15,009	(398,985)	(2,495)
Share-based compensation expense	7,874	7,743	6,746
Amortization of debt premiums, discounts and related financing costs	2,794	3,195	2,101
Loss on interest rate derivatives	560	0	0
Loss on extinguishment of debt	34	0	1,178
Loss on extinguishment of debt	0	764	0
Changes in other assets	(7,258)	(10,086)	(8,674)
Changes in other liabilities	(15,794)	(4,801)	(2,367)
Net cash provided by operating activities	112,991	130,923	147,369
Cash flows from investing activities
Real estate acquisitions, net	0	(528,589)	(106,400)
Net cash received from sale of real estate	152,889	706,064	174,297
Capital improvements to real estate	(58,095)	(68,456)	(71,070)
Development in progress	(28,812)	(47,492)	(34,806)
Non-real estate capital improvements	(222)	(491)	(963)
Net cash provided by (used in) investing activities	65,760	61,036	(38,942)
Cash flows from financing activities
Line of credit (repayments) borrowings, net	(14,000)	(132,000)
Line of credit (repayments) borrowings, net			22,000
Dividends paid	(99,080)	(96,361)	(95,059)
Principal payments – mortgage notes payable	(46,567)	(12,724)	(170,081)
Proceeds from notes payable	350,000	0	0
Repayments of notes payable	(250,000)	0	0
Repayments of unsecured term loan debt	(300,000)	(450,000)	(150,000)
Proceeds from term loan	150,000	450,000	250,000
Settlement of interest rate derivatives	(20,948)	0	0
Payment of financing costs	(3,284)	(1,303)	(5,650)
Distributions to noncontrolling interests	(14)	(15)	(14)
Proceeds from dividend reinvestment program	2,121	4,755	1,973
Net proceeds from equity issuances	48,355	54,916	35,472
Payment of tax withholdings for restricted share awards	(1,782)	(2,116)	(2,051)
Net cash used in financing activities	(185,199)	(184,848)	(113,410)
Net (decrease) increase in cash, cash equivalents and restricted cash	(6,448)	7,111	(4,983)
Cash, cash equivalents and restricted cash at beginning of year	14,751	7,640	12,623
Cash, cash equivalents and restricted cash at end of year	8,303	14,751	7,640
Supplemental disclosure of cash flow information:
Cash paid for interest, net of capitalized interest expense	37,542	50,999	49,058
Change in accrued capital improvements and development costs	(5,850)	7,908	(2,769)
Reconciliation of cash, cash equivalents and restricted cash:
Cash, cash equivalents and restricted cash	$ 14,751	$ 7,640	$ 7,640

Nature of Business

Nature of Business	12 Months Ended
	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Business	NOTE 1: NATURE OF BUSINESS Washington Real Estate Investment Trust (“WashREIT”), 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 portfolio of multifamily and commercial properties. U.S. Federal Income Taxes We believe that we qualify as a REIT under Sections 856-860 of the Internal Revenue Code of 1986, as amended (the "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, 2020, we sold our interests in the following properties (in thousands): Disposition Date Property Type (Loss) Gain on Sale April 21, 2020 John Marshall II Office $ (6,855) December 2, 2020 Monument II Office $ (8,595) December 17, 2020 1227 25th Street Office 1,125 Total 2020 $ (14,325) June 26, 2019 Quantico Corporate Center (1) Office $ (1,046) July 23, 2019 Shopping Center Portfolio (2) Retail 333,023 August 21, 2019 Frederick Crossing and Frederick County Square Retail 9,507 August 27, 2019 Centre at Hagerstown Retail (3,506) December 19, 2019 1776 G Street Office 61,007 Total 2019 $ 398,985 January 19, 2018 Braddock Metro Center Office $ — June 28, 2018 2445 M Street Office 2,495 Total 2018 $ 2,495 ______________________________ (1) Consists of 925 and 1000 Corporate Drive. (2) Consists of five retail properties: Gateway Overlook, Wheaton Park, Olney Village Center, Bradlee Shopping Center and Shoppes of Foxchase. Seven of the eight retail properties sold during 2019 were identified for deferred exchanges under Section 1031 of the Code (see note 3). We acquired eight multifamily replacement properties (see note 3) during 2019. The taxable gains for 1776 G Street and a portion of the Shopping Center Portfolio proceeds not reinvested in the deferred exchange were distributed to shareholders through quarterly dividends in 2019. 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. As of both December 31, 2020 and 2019, our TRSs had a deferred tax asset of $1.4 million that was fully reserved. As of December 31, 2019, we had deferred state and local tax liabilities of $0.6 million. These deferred tax liabilities were primarily related to temporary differences in the timing of the recognition of revenue, amortization and depreciation. We did not have deferred state or local tax liabilities as of December 31, 2020. Beginning in 2018, ordinary taxable income per share is equal to the Section 199A dividend that was created by the Tax Cuts and Jobs Act. The following is a breakdown of the taxable percentage of our dividends for the three years ended December 31, 2020, 2019 and 2018 (unaudited): 2020 2019 2018 Ordinary income/Section 199A dividends 36 % 80 % 29 % Return of capital 64 % 20 % 71 % Qualified dividends — % — % — % Unrecaptured Section 1250 gain — % — % — % Capital gain — % — % — %

Summary of Significant Accounti

Summary of Significant Accounting Policies and Basis of Presentation	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Summary of Significant Accounting Policies and Basis of Presentation	NOTE 2: 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 WashREIT and our subsidiaries and entities in which WashREIT has a controlling financial 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 Standards Standards Adopted Standard/Description Effective Date and Adoption Considerations Effect on Financial Statements or Other significant Matters ASU 2016-13, Measurement of Credit Losses on Financial Instruments . This standard requires financial assets measured at an amortized cost basis, including trade receivables, to be presented at the net amount expected to be collected. This standard does not apply to receivables arising from operating leases accounted for in accordance with Topic 842. We adopted the new standard as of January 1, 2020. The adoption of the new standard did not have a material impact on our consolidated financial statements. ASU 2018-15, Intangibles - Goodwill and Other - Internal-Use Software . This standard requires a customer in a cloud computing arrangement that is a service contract to follow the internal-use software guidance to determine which implementation costs to capitalize as assets. We adopted the new standard as of January 1, 2020. The adoption of the new standard did not have a material impact on our consolidated financial statements. Standard/Description Effective Date and Adoption Considerations Effect on Financial Statements or Other significant Matters ASU 2020-04, Reference Rate Reform - Facilitation of the Effects of Reference Rate Reform on Financial Reporting . This standard contains optional practical expedients and exceptions for applying Generally Accepted Accounting Principles (“GAAP”) to contracts, hedging relations, and other transactions affected by reference rate reform if certain criteria are met. We elected certain optional practical expedients as of January 1, 2020. The guidance in ASU 2020-04 is optional and may be elected over time as reference rate reform activities occur. As of January 1, 2020, we have elected to apply the hedge accounting expedients related to probability and the assessments of effectiveness for future LIBOR-indexed cash flows to assume that the index upon which future hedged transactions will be based matches the index on the corresponding derivatives. Application of these expedients preserves the presentation of derivatives consistent with past presentation. We continue to evaluate the impact of the guidance and may apply other elections as applicable as additional changes in the market occur. COVID-19 Lease Modification Accounting Relief In April 2020, the Financial Accounting Standards Board (“FASB”) staff issued a question-and-answer document (“Q&A”) that addresses their belief that the guidance on lease modifications in GAAP does not contemplate concessions being executed as rapidly as they were executed as a result of the major financial crisis arising from the COVID-19 pandemic. Under ASC 842, Leases , we evaluate, on a lease by lease basis, if a lease concession is the result of a new arrangement reached with the tenant, which could result in lease modification accounting, or if a lease concession is contemplated in the existing lease agreement, which is precluded from lease modification accounting. In the Q&A, the staff stated that entities may elect to not evaluate whether a concession provided by a lessor to a lessee in response to the COVID-19 pandemic is a lease modification. This election must be applied consistently to leases with similar characteristics and circumstances. The election permits entities, if certain criteria are met, to account for concessions as if they were contemplated in the existing contract or evaluate the lease concessions for lease modification accounting. If elected, abatement concessions are accounted for as negative variable rental revenue and rent deferrals are accounted for as if the lease is unchanged. We have elected to utilize the relief provided by the FASB staff. This election did not have a material impact on our consolidated financial statements as of December 31, 2020, and we do not expect material impacts in future periods. Revenue Recognition We lease multifamily properties under operating leases with terms of generally one year or less. We lease commercial properties 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. In certain commercial leases, variable lease income, such as percentage rent, is recognized when rents are earned. We recognize rental income and rental abatements from our multifamily and commercial leases on a straight-line basis over the lease term. Recognition of rental income commences when control of the leased space has been transferred to the tenant. We recognize gains on sales of real estate when we have executed a contract for sale of the asset, transferred controlling financial interest in the asset to the buyer and determined that it is probable that we will collect substantially all of the consideration for the asset. Our real estate sale transactions typically meet these criteria at closing. 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 monthly parking revenues as earned. We recognize transient parking revenue when our performance obligation is met. Rents and Other Receivables Lease related receivables, which include contractual amounts accrued and unpaid from tenants and accrued straight-line rents receivable, are reduced for credit losses. Such amounts are recognized as a reduction to real estate rental revenues. We evaluate the collectability of lease receivables monthly using several factors including a lessee’s creditworthiness. We recognize the credit loss on lease related receivables when, in the opinion of management, collection of substantially all lease payments is not probable. When collectability is determined not probable, any lease income recognized subsequent to recognizing the credit loss is limited to the lesser of the lease income reflected on a straight-line basis or cash collected. The adoption of ASU 2016-02 resulted in an adjustment to our opening distributions in excess of net income balance of $0.9 million, associated with lease related receivables where collection of substantially all operating lease payments was not probable as of January 1, 2019. 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 direct and incremental 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 operations. 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 leasing incentives associated with the successful negotiation of leases on a straight-line basis against revenue over the terms of the respective leases. We record the amortization of deferred leasing incentives as a reduction in 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 in 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 40 years. We also capitalize costs incurred in connection with our development projects, including 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 begins when the activities and related expenditures commence and ceases when the project is substantially complete and ready for its intended use, at which time the project is placed into 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 $103.4 million, $101.7 million and $82.9 million during the years ended December 31, 2020, 2019 and 2018, respectively. We charge maintenance and repair costs that do not extend an asset’s useful life to expense as incurred. Interest expense from continuing operations and interest capitalized to real estate assets related to development and major renovation activities for the three years ended December 31, 2020 were as follows (in thousands): Year Ended December 31, 2020 2019 2018 Total interest incurred $ 39,524 $ 56,948 $ 52,592 Capitalized interest (2,219) (3,214) (2,091) Interest expense, net of capitalized interest $ 37,305 $ 53,734 $ 50,501 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. Estimates of undiscounted cash flows are based on forward-looking assumptions, including annual and residual cash flows and our estimated holding period for each property. Such assumptions involve a high degree of judgment and could be affected by future economic and market conditions. When determining if a property has indicators of impairment, we evaluate the property's occupancy, our expected holding period for the property, strategic decisions regarding the property's future operations or development and other market factors. 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. Acquisitions The properties we acquire typically are not businesses as defined by ASU 2017-01, Business Combinations (Topic 805) - Clarifying the Definition of a Business . Per this definition, 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. We therefore account for such acquisitions as asset acquisitions. Acquisition costs are capitalized and identifiable assets (including physical assets and in-place leases), liabilities assumed and any noncontrolling interests are measured by allocating the cost of the acquisition on a relative fair value basis. Acquisitions executed prior to our adoption of ASU 2017-01 as of January 1, 2017 were accounted for as business combinations. 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 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, 2020 and 2019. 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 prior to the expiration date, 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. Software Developed for Internal Use The costs of software developed for internal use that qualify for capitalization are included with Prepaid expenses and other assets on our consolidated balance sheets. These capitalized costs include external direct costs utilized in developing or obtaining the applications and expenses for employees who are directly associated with the development of the applications. Capitalization of such costs begins when the preliminary project stage is complete and continues until the project is substantially complete and is ready for its intended purpose. Completed projects are amortized on a straight-line basis over their estimated useful lives. Held for Sale and Discontinued Operations We classify properties as held for sale when they meet the necessary criteria, which include: (a) senior management commits to a plan to sell the assets; (b) the assets are available for immediate sale in their present condition subject only to terms that are usual and customary for sales of such assets; (c) an active program to locate a buyer and other actions required to complete the plan to sell the assets has been initiated; (d) the sale of the assets is probable and transfer of the assets is expected to qualify for recognition as a completed sale within one year; (e) the assets are being actively marketed for sale at a price that is reasonable in relation to its current fair value; and (f) 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. 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. 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 operations 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 operations for all periods presented. 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 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 operating partnership units under the if-converted method and our share based awards with performance conditions prior to the grant date and all market condition awards 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. We account for forfeitures as they occur. 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, 2020 and 2019, 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 2017 through 2019 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 expenses. Derivatives

Real Estate

Real Estate	12 Months Ended
	Dec. 31, 2020
Real Estate [Abstract]
Real Estate	NOTE 3: REAL ESTATE As of December 31, 2020 and 2019, our real estate investment portfolio classified as income producing property that is held and used, at cost, consists of properties valued as follows (in thousands): December 31, 2020 2019 Multifamily $ 1,606,085 $ 1,469,011 Office 1,214,481 1,329,722 Other 163,051 160,489 $ 2,983,617 $ 2,959,222 Our results of operations are dependent on the overall economic health of our markets, tenants and the specific segments in which we own properties. All property types 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, 2020, no property accounted for more than approximately 10% of total assets. No single property or tenant accounted for more than 10% of real estate rental revenue. We have properties under development/redevelopment and held for current or future development. The cost of our real estate portfolio under development or held for future development as of December 31, 2020 and 2019 is as follows (in thousands): December 31, 2020 2019 Multifamily $ 36,493 $ 123,071 Office 478 478 Other 644 644 $ 37,615 $ 124,193 As of December 31, 2020, we have invested $133.5 million, including the cost of acquired land, in Trove, a 401-unit multifamily development adjacent to The Wellington. During 2020, we substantially completed major construction activities for Trove's base building and garage and delivered 374 units. As of December 31, 2020, we have placed into service assets totaling $126.4 million. We expect to place the remainder of the Trove development costs into service during the first quarter of 2021. We have also invested $28.6 million, including the cost of acquired land, in a multifamily development adjacent to Riverside Apartments. In addition, in our multifamily and office segments, we continue to capitalize qualifying costs on several other projects with minor development activity necessary to ready each project for its intended use. 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 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, 2020 were as follows: Acquisition Date Property Type # of units (unaudited) Rentable Contract April 30, 2019 Assembly Portfolio - Virginia (1) Multifamily 1,685 N/A $ 379,100 June 27, 2019 Assembly Portfolio - Maryland (2) Multifamily 428 N/A 82,070 July 23, 2019 Cascade at Landmark Multifamily 277 N/A 69,750 2,390 $ 530,920 January 18, 2018 Arlington Tower Office N/A 391,000 $ 250,000 ______________________________ (1) Consists of Assembly Alexandria, Assembly Manassas, Assembly Dulles, Assembly Leesburg and Assembly Herndon. (2) Consists of Assembly Germantown and Assembly Watkins Mill. The Assembly Portfolio - Virginia and Assembly Portfolio - Maryland properties are collectively the “Assembly Portfolio.” The purchases of the Assembly Portfolio and Cascade at Landmark were structured as exchanges under Section 1031 of the Code in a manner such that legal title was held by a 1031 exchange facilitator until certain identified properties were sold and the deferred exchanges were completed. We retained all of the legal and economic benefits and obligations related to the Assembly Portfolio and Cascade at Landmark. As such, the Assembly Portfolio and Cascade at Landmark were considered to be variable interest entities until legal title was transferred to us upon completion of the 1031 exchanges, which occurred during the third quarter of 2019. We consolidated the assets and liabilities of the Assembly Portfolio and Cascade at Landmark because we determined that WashREIT was the primary beneficiary of these properties. The results of operations from acquired operating properties are included in the consolidated statements of operations as of their acquisition dates. We did not have any acquisition activity for the year ended December 31, 2020. The revenue and earnings of our acquisitions during their year of acquisition for the two years ended December 31, 2019 are as follows (in thousands): Year Ended December 31, 2019 2018 Real estate rental revenue $ 27,641 $ 22,389 Net (loss) income (10,167) 3,623 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 assumed liabilities on a relative fair value basis. We recorded the total cost of the above acquisitions as follows (in thousands): 2019 2018 Land $ 92,391 $ 63,970 Buildings and improvements 423,663 142,900 Tenant origination costs — 13,625 Leasing commissions/absorption costs 15,474 27,465 Net lease intangible assets — 3,142 Net lease intangible liabilities — (545) Total $ 531,528 $ 250,557 The difference in the total cost of the 2019 acquisitions of $531.5 million and the cash paid for the acquisitions per the consolidated statements of cash flows of $528.6 million is primarily due to credits received at settlement totaling $2.9 million. The difference in the total contract purchase price of $250.0 million for the 2018 acquisition and cash paid for the acquisition per the consolidated statements of cash flows of $106.4 million is primarily due to a mortgage note assumed and repaid at settlement ($135.5 million), an acquisition deposit made during 2017 ($6.3 million) and a net credit to the buyer for certain expenditures ($2.4 million), partially offset by capitalized acquisition related costs ($0.6 million). Balances, net of accumulated depreciation or amortization, as appropriate, of the components of the fair value of in-place leases at December 31, 2020 and 2019 were as follows (in thousands): December 31, 2020 2019 Gross Carrying Value Accumulated Amortization Net Gross Carrying Value Accumulated Amortization Net Tenant origination costs $ 43,536 $ 30,096 $ 13,440 $ 50,155 $ 33,364 $ 16,791 Leasing commissions/absorption costs 107,102 83,588 23,514 122,348 92,401 29,947 Net lease intangible assets 11,595 9,390 2,205 15,183 11,964 3,219 Net lease intangible liabilities 27,809 20,247 7,562 29,836 20,854 8,982 Below-market ground lease intangible asset 12,080 2,472 9,608 12,080 2,282 9,798 Amortization of these combined components during the three years ended December 31, 2020, 2019 and 2018 was as follows (in thousands): Year Ended December 31, 2020 2019 2018 Depreciation and amortization expense $ 9,997 $ 27,123 $ 22,361 Real estate rental revenue increase, net (406) (924) (1,225) $ 9,591 $ 26,199 $ 21,136 Amortization of these combined components over the next five years and thereafter is projected to be as follows (in thousands): Depreciation and amortization expense Real estate rental revenue, net increase Total 2021 $ 8,576 $ (547) $ 8,029 2022 8,078 (736) 7,342 2023 6,032 (974) 5,058 2024 5,264 (862) 4,402 2025 4,231 (777) 3,454 Thereafter 14,380 (1,460) 12,920 Properties Sold and Held for Sale 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 through the date of sale. We classified as held for sale or sold our interests in the following properties during the three years ended December 31, 2020: Disposition Date Property Type # of units (unaudited) Rentable Contract (Loss) Gain on Sale April 21, 2020 John Marshall II Office N/A 223,000 $ 57,000 $ (6,855) December 2, 2020 Monument II Office N/A 207,000 53,000 (8,595) December 17, 2020 1227 25th Street Office N/A 135,000 53,500 1,125 Total 2020 565,000 $ 163,500 $ (14,325) June 26, 2019 Quantico Corporate Center (1) Office N/A 272,000 $ 33,000 $ (1,046) July 23, 2019 Shopping Center Portfolio (2) Retail N/A 800,000 485,250 333,023 August 21, 2019 Frederick Crossing and Frederick County Square Retail N/A 520,000 57,500 9,507 August 27, 2019 Centre at Hagerstown Retail N/A 330,000 23,500 (3,506) December 19, 2019 1776 G Street Office N/A 262,000 129,500 61,007 Total 2019 2,184,000 $ 728,750 $ 398,985 January 19, 2018 Braddock Metro Center Office N/A 356,000 $ 93,000 $ — June 28, 2018 2445 M Street Office N/A 292,000 101,600 2,495 Total 2018 648,000 $ 194,600 $ 2,495 ______________________________ (1) Consists of 925 and 1000 Corporate Drive. (2) Consists of five retail properties: Gateway Overlook, Wheaton Park, Olney Village Center, Bradlee Shopping Center and Shoppes of Foxchase. We have fully transferred control of the assets associated with these disposed properties and do not have continuing involvement in the operations of these properties. In November 2020, we executed a purchase and sale agreement to sell 1227 25th Street for a contract sale price of $53.5 million and closed on the sale on December 17, 2020, recognizing a gain on sale of real estate of $1.1 million. In December 2020, we executed a purchase and sale agreement to sell Monument II for a contract sale price of $53.0 million and closed on the sale on December 2, 2020, recognizing a loss on sale of real estate of $8.6 million. In December 2019, we executed a purchase and sale agreement to sell John Marshall II for a contract sale price of $63.4 million. Upon execution of the purchase and sale agreement, the property met the criteria for classification as held for sale. In April 2020, we executed an amendment to the purchase and sale agreement which decreased the contract sale price to $57.0 million and closed on the sale on April 21, 2020, recognizing a loss on sale of real estate of $6.9 million. During the second quarter of 2019, we sold Quantico Corporate Center, an office property in Stafford, Virginia, consisting of two office buildings totaling 272,000 square feet, for a contract sale price of $33.0 million, recognizing a loss on sale of real estate of $1.0 million. Prior to the sale, due to the negotiations to sell the property, we evaluated Quantico Corporate Center for impairment and recognized an $8.4 million impairment charge during the first quarter of 2019 in order to reduce the carrying value of the property to its estimated fair value. We based this fair valuation on the expected sale price from a potential sale. There were few observable market transactions for similar properties. This fair valuation falls into Level 2 of the fair value hierarchy due to its reliance on a quoted price in a market that is not active. In June 2019, we had entered into two separate purchase and sale agreements with two separate buyers to sell the Shopping Center Portfolio and the Power Center Portfolio (Frederick Crossing, Frederick County Square and Centre at Hagerstown). As of June 30, 2019, we received a non-refundable deposit from the potential buyer of the Shopping Center Portfolio and expected to receive a non-refundable deposit from the potential buyer of the Power Center Portfolio in July 2019, and the properties in the Retail Portfolio (as defined below) met the criteria for classification as held for sale. We closed on the Shopping Center Portfolio sale transaction on July 23, 2019 for a contract sales price of $485.3 million, recognizing a gain on sale of real estate of $333.0 million. Prior to closing on the disposition of the Shopping Center Portfolio, we prepaid the mortgage note secured by Olney Village Center (a property in the Shopping Center Portfolio), incurring a loss on extinguishment of debt of approximately $0.8 million which we recognized in the third quarter of 2019. In the third quarter of 2019, the purchase and sale agreement to sell the Power Center Portfolio was amended to include only Frederick Crossing and Frederick County Square. We closed on the sales of these assets on August 21, 2019 for a contract sales price of $57.5 million, recognizing a gain on sale of real estate of $9.5 million. Following the amendment to the purchase and sale agreement to sell the Power Center Portfolio, we marketed Centre at Hagerstown for sale and identified a separate buyer. We closed on the sale of this asset on August 27, 2019, recognizing a loss on sale of real estate of $3.5 million. References to the “Retail Portfolio” include the Shopping Center Portfolio and the Power Center Portfolio. The disposition of the Retail Portfolio represents a strategic shift that had a major effect on our financial results and we have accordingly reported the Retail Portfolio as discontinued operations. The Retail Portfolio represents assets generating a majority of the revenue from our retail properties and we have determined that our retail line of business is no longer a reportable segment (see note 14). In October 2019, we renewed and extended our lease with the World Bank at 1776 G Street NW, an office property in Washington, D.C., through December 31, 2025. In December 2019, we sold the property to the World Bank for a contract sale price of $129.5 million, recognizing a gain on sale of real estate of $61.0 million. During the first quarter of 2018, we sold Braddock Metro Center, a 356,000 square foot office property in Alexandria, Virginia for a contract sales price of $93.0 million. Due to then-ongoing negotiations to sell the property, we evaluated Braddock Metro Center for impairment and recognized a $9.1 million impairment charge during 2017 in order to reduce the carrying value of the property to its estimated fair value, less selling costs. We based this fair valuation on the expected sale price from a potential sale. There are few observable market transactions for similar properties. This fair valuation falls into Level 2 of the fair value hierarchy due to its reliance on a quoted price in a market that is not active. During the first quarter of 2018, we executed a purchase and sale agreement to sell 2445 M Street, a 292,000 square foot office property in Washington, D.C., for a contract sales price of $100.0 million, with settlement originally scheduled for the third quarter of 2018. During 2017, we evaluated 2445 M Street for impairment and recognized a $24.1 million impairment charge in order to reduce the carrying value of the property to its estimated fair value. Upon execution of the purchase and sale agreement, the property met the criteria for classification as held for sale. Due to the property’s classification as held for sale, we recorded an additional impairment charge of $1.9 million in the first quarter of 2018 in order to reduce the carrying value of the property to its estimated fair value, less estimated selling costs. We based this fair value on the expected sales price from a potential sale. There are few observable market transactions for similar properties. This fair valuation falls into Level 2 of the fair value hierarchy due to its reliance on a quoted price in a market that is not active. During the second quarter of 2018, we executed an amendment to the purchase and sale agreement which increased the contract sales price to $101.6 million and advanced the settlement date. On June 28, 2018, we sold 2445 M Street, recognizing a gain on sale of real estate of $2.5 million. Discontinued Operations The results of the Retail Portfolio are classified as discontinued operations and are summarized as follows (amounts in thousands, except for share data): Year Ended December 31, 2019 2018 Real estate rental revenue $ 28,200 $ 45,160 Real estate expenses (6,803) (10,638) Depreciation and amortization (4,926) (9,402) Interest expense (313) (643) Loss on extinguishment of debt (764) — Gain on sale of real estate 339,024 — Income from discontinued operations $ 354,418 $ 24,477 Basic net income per share $ 4.39 $ 0.31 Diluted net income per share $ 4.39 $ 0.31 Capital expenditures $ 809 $ 2,138 All assets and liabilities related to the Retail Portfolio were sold as of December 31, 2019.

Lease Accounting

Lease Accounting	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Lease Accounting	NOTE 4: LEASE ACCOUNTING Leasing as a Lessor Future Minimum Rental Income As of December 31, 2020, non-cancelable commercial operating leases provide for future minimum rental income from continuing operations as follows (in thousands): 2021 $ 122,062 2022 109,939 2023 93,467 2024 80,793 2025 63,923 Thereafter 215,443 $ 685,627 Apartment leases are not included as the terms are generally for one year or less. Rental income under most of these commercial leases increase in future years based on agreed-upon percentages or in some instances, changes in the Consumer Price Index. Leasing as a Lessee 2000 M Street, an office property in Washington, D.C., is subject to an operating ground lease with a remaining term of 50 years. Rental payments under this lease are subject to percentage rent variable payments, which are not included as part of our measurement of straight-line rental expense. We recognized straight-line rental expense of $0.3 million during each of the three years ended December 31, 2020. We recognized variable rental payments of $0.8 million, $0.9 million and $0.9 million during the years ended December 31, 2020, 2019 and 2018 respectively. We recognized a right-of-use asset (included in Income producing property) and lease liability (included in Accounts payable and other liabilities) of $4.2 million. We used a discount rate of approximately 5.9%, which was derived from our assessment of securitized rates for similar assets and credit quality. We recognized $0.2 million and $0.3 million of right-of-use asset and lease liability amortization during the years ended December 31, 2020 and 2019, respectively. The following table sets forth the undiscounted cash flows of our scheduled obligations for future minimum payments on our operating ground lease as of December 31, 2020 and a reconciliation of those cash flows to the operating lease liability as of December 31, 2020 (in thousands): 2021 $ 260 2022 260 2023 260 2024 260 2025 260 Thereafter 11,635 12,935 Imputed interest (9,203) Lease liability $ 3,732
Lease Accounting	NOTE 4: LEASE ACCOUNTING Leasing as a Lessor Future Minimum Rental Income As of December 31, 2020, non-cancelable commercial operating leases provide for future minimum rental income from continuing operations as follows (in thousands): 2021 $ 122,062 2022 109,939 2023 93,467 2024 80,793 2025 63,923 Thereafter 215,443 $ 685,627 Apartment leases are not included as the terms are generally for one year or less. Rental income under most of these commercial leases increase in future years based on agreed-upon percentages or in some instances, changes in the Consumer Price Index. Leasing as a Lessee 2000 M Street, an office property in Washington, D.C., is subject to an operating ground lease with a remaining term of 50 years. Rental payments under this lease are subject to percentage rent variable payments, which are not included as part of our measurement of straight-line rental expense. We recognized straight-line rental expense of $0.3 million during each of the three years ended December 31, 2020. We recognized variable rental payments of $0.8 million, $0.9 million and $0.9 million during the years ended December 31, 2020, 2019 and 2018 respectively. We recognized a right-of-use asset (included in Income producing property) and lease liability (included in Accounts payable and other liabilities) of $4.2 million. We used a discount rate of approximately 5.9%, which was derived from our assessment of securitized rates for similar assets and credit quality. We recognized $0.2 million and $0.3 million of right-of-use asset and lease liability amortization during the years ended December 31, 2020 and 2019, respectively. The following table sets forth the undiscounted cash flows of our scheduled obligations for future minimum payments on our operating ground lease as of December 31, 2020 and a reconciliation of those cash flows to the operating lease liability as of December 31, 2020 (in thousands): 2021 $ 260 2022 260 2023 260 2024 260 2025 260 Thereafter 11,635 12,935 Imputed interest (9,203) Lease liability $ 3,732

Mortgage Note Payable

Mortgage Note Payable	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Mortgage Note Payable	NOTE 5: MORTGAGE NOTE PAYABLE In January 2020, we prepaid the $45.6 million mortgage note secured by Yale West, which was scheduled to mature in 2052. As a result of the transaction, we recognized a gain on extinguishment of debt of $0.5 million related to the write-off of an unamortized mortgage premium of $1.4 million, partially offset by a prepayment penalty of $0.9 million. Following this repayment, we have no outstanding mortgage notes as of December 31, 2020. As of December 31, 2019, we had one outstanding mortgage notes payable, collateralized by a building and related land from our portfolio, as follows (in thousands): Properties Assumption/Issuance Date (1) Effective Interest Rate (2) December 31, 2019 Yale West 2/21/2014 3.75 % $ 45,654 Premiums and discounts, net 1,470 Debt issuance costs, net (50) $ 47,074 ______________________________ (1) This mortgage was assumed with the acquisition of the collateralized property. 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. Principal and interest were payable monthly until the maturity date, at which time all unpaid principal and interest were payable in full. Total cost basis of the above mortgaged property was $77.4 million at December 31, 2019.

Unsecured Lines of Credit Payab

Unsecured Lines of Credit Payable	12 Months Ended
	Dec. 31, 2020
Unsecured Lines of Credit Payable
Debt Instrument [Line Items]
Unsecured Lines of Credit Payable	NOTE 6: UNSECURED LINES OF CREDIT PAYABLE During the first quarter of 2018, we entered into an amended and restated credit agreement (“Credit Agreement”) which provides for a $700.0 million unsecured revolving credit facility (“Revolving Credit Facility”), the continuation of an existing $150.0 million unsecured term loan (“2015 Term Loan”) and an additional $250.0 million unsecured term loan (“2018 Term Loan”). The Revolving Credit Facility has a four-year term ending in March 2022, with two six-month extension options. The Credit Agreement has an accordion feature that allows us to increase the facility up to $1.5 billion in the aggregate, to the extent the lenders agree to provide additional revolving loan commitments or term loans. The 2018 Term Loan increases and replaces the $150.0 million unsecured term loan, initially entered into on July 22, 2016 (“2016 Term Loan”), that was scheduled to mature in July 2023. The 2018 Term Loan is scheduled to mature in July 2023 and bears interest at a rate of either one month LIBOR plus a margin ranging from 0.85% to 1.75% or the base rate plus a margin ranging from 0.0% to 0.75% (in each case depending upon WashREIT’s credit rating). We used the $100.0 million of additional proceeds from the 2018 Term Loan primarily to repay outstanding borrowings on the Revolving Credit Facility. We had previously used interest rate derivatives to effectively fix the interest rate of the 2016 Term Loan. These interest rate derivatives now effectively fix the interest rate on a $150.0 million portion of the 2018 Term Loan at 2.31%. In March 2018, we entered into interest rate derivatives that commenced on June 29, 2018 to effectively fix the interest rate on the remaining $100.0 million of the 2018 Term Loan at 3.71%. The 2018 Term Loan has an all-in fixed interest rate of 2.87%. The amount of the Revolving Credit Facility unused and available at December 31, 2020 was as follows (in thousands): Committed capacity $ 700,000 Borrowings outstanding (42,000) Unused and available $ 658,000 We executed borrowings and repayments on the Revolving Credit Facility during 2020 as follows (in thousands): Balance at December 31, 2019 $ 56,000 Borrowings 732,000 Repayments (746,000) Balance at December 31, 2020 $ 42,000 The Revolving Credit Facility bears interest at a rate of either one month LIBOR plus a margin ranging from 0.775% to 1.55% or the base rate plus a margin ranging from 0.0% to 0.55% (in each case depending upon WashREIT’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 LIBOR market index rate plus 1.0%. In addition, the Revolving Credit Facility requires the payment of a facility fee ranging from 0.10% to 0.30% (depending on WashREIT’s credit rating) on the $700.0 million committed capacity, without regard to usage. As of December 31, 2020, the interest rate on the facility was LIBOR plus 1.00%, the one month LIBOR was 0.14% and the facility fee was 0.20%. All outstanding advances for the Revolving Credit Facility are due and payable upon maturity in March 2022, 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. For the three years ended December 31, 2020, we recognized interest expense (excluding facility fees) and facility fees as follows (in thousands): Year Ended December 31, 2020 2019 2018 Interest expense (excluding facility fees) $ 3,035 $ 6,554 $ 6,843 Facility fees 1,423 1,400 1,371 The Revolving Credit Facility contains and the prior unsecured credit facility that it replaced contained certain financial and non-financial covenants, all of which we have met as of December 31, 2020 and 2019. 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, 2020 as follows (in thousands, except percentage amounts): Year Ended December 31, 2020 2019 2018 Total revolving credit facilities at December 31 $ 700,000 $ 700,000 $ 700,000 Borrowings outstanding at December 31 42,000 56,000 188,000 Weighted average daily borrowings during the year 204,809 196,074 230,934 Maximum daily borrowings during the year 456,000 300,000 429,000 Weighted average interest rate during the year 1.48 % 3.34 % 2.96 % Weighted average interest rate on borrowings outstanding at December 31 1.15 % 2.73 % 3.52 % The covenants under our Credit Agreement 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

Notes Payable

Notes Payable	12 Months Ended
	Dec. 31, 2020
Notes payable
Debt Instrument [Line Items]
Notes Payable	NOTE 7: NOTES PAYABLE Our unsecured notes and term loans outstanding as of December 31, 2020 and 2019 are as follows (in thousands): Effective December 31, Payoff Date/ Coupon/Stated Rate Rate (1) 2020 2019 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 % 300,000 300,000 10/15/2022 2018 Term Loan (3) 1 Month LIBOR + 110 basis points 2.87 % 250,000 250,000 7/21/2023 30-Year Unsecured Notes 7.25 % 7.36 % 50,000 50,000 2/25/2028 Green Bonds 3.44 % 4.09 % 350,000 — 12/29/2030 Total principal 950,000 1,000,000 Premiums and discounts, net (456) (797) Deferred issuance costs, net (4,174) (2,481) Total $ 945,370 $ 996,722 ______________________________ (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 8). (2) No principal amounts are due prior to maturity. (3) The 2018 Term Loan increased and replaced the 2016 Term Loan (see note 6). In April 2020, we used borrowings from our Revolving Credit Facility to prepay all $250.0 million of our 4.95% 10-year unsecured notes without penalty. On May 5, 2020, we entered into a one-year, $150.0 million unsecured term loan facility (“2020 Term Loan”), maturing on May 5, 2021 with a one-year extension option. The 2020 Term Loan bears interest at LIBOR + 1.50%, which margin is subject to change based on our credit ratings, with a 0.50% floor for the LIBOR rate. We used the proceeds to repay borrowings under our Revolving Credit Facility. We repaid in full the 2020 Term Loan on November 30, 2020. On September 29, 2020, we entered into a note purchase agreement to issue $350.0 million aggregate principal amount of 3.44% senior unsecured 10-year notes payable (the “Green Bonds”). The effective interest rate under the Green Bonds, including amortization of the associated interest rate swaps (see note 8), is 4.09%. The closing and full funding of the Green Bonds occurred on December 17, 2020. We incurred $2.6 million of debt issuance costs associated with the Green Bonds which are reported on our consolidated balance sheets as an offset to their related debt. The Green Bonds are senior unsecured obligations of WashREIT and rank equal in right to payment with all other senior unsecured indebtedness of WashREIT. The proceeds of the sale of the Green Bonds were and will be used to finance or refinance recently completed and future green building and energy efficiency, sustainable water and wastewater management and renewable energy projects (“Eligible Green Projects”). In the fourth quarter of 2020, we repaid all $150.0 million of borrowings on the 2015 Term Loan and all $150.0 million of borrowings on the 2020 Term Loan. As a result of these transactions, we recognized a loss on extinguishment of debt of $0.3 million. The note purchase agreement contains customary financial covenants, including a maximum total leverage ratio, a maximum secured leverage ratio, a minimum fixed charge coverage ratio, a minimum unencumbered interest coverage ratio, and a maximum unencumbered leverage ratio. The note purchase agreement also contains restrictive covenants that, among other things, restrict the ability of WashREIT and its subsidiaries to enter into transactions with affiliates, consolidate or merge or transfer or lease all or substantially all of its assets, create liens, make dividends and distributions if an event of default exists, or substantially change the general nature of our business. Such financial and restrictive covenants are substantially similar to the corresponding covenants contained in our Credit Agreement. The note purchase agreement also contains customary events of default, including payment defaults, cross defaults with certain other indebtedness, breaches of certain covenants and bankruptcy events. In the case of an event of default, we will generally be prohibited from paying any dividends, subject to certain exceptions including payment of dividends necessary to maintain REIT status, and the Purchasers may, among other remedies, accelerate the payment of all obligations. In the event of a change in control of WashREIT, we must offer to prepay the Green Bonds at par. On April 30, 2019, we entered into a six-month, $450.0 million unsecured term loan facility (“2019 Term Loan”), maturing on October 30, 2019 with an option to extend for a six-month period. The 2019 Term Loan bore interest, at WashREIT’s option, at a rate of either LIBOR plus a margin ranging from 0.75% to 1.65% or the base rate plus a margin ranging 0.0% to 0.65% (in each case depending upon WashREIT’s credit rating). The base rate was 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%. At WashREIT’s election, the 2019 Term Loan had an interest rate of one-week LIBOR plus 100 basis points, based on WashREIT’s current unsecured debt rating. The 2019 Term Loan was used to fund the acquisition of the Assembly Portfolio (see note 3). During the third quarter of 2019, we repaid the $450.0 million of borrowings on the 2019 Term Loan with proceeds from the sale of the Retail Portfolio (see note 3). The required principal payments on the unsecured notes and term loans as of December 31, 2020 are as follows (in thousands): 2021 $ — 2022 300,000 2023 250,000 2024 — 2025 — Thereafter 400,000 $ 950,000

Derivative Instruments

Derivative Instruments	12 Months Ended
	Dec. 31, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments	NOTE 8: 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 $150.0 million 2015 Term Loan (see note 6) to an all-in fixed interest rate of 2.72% 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 $150.0 million 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 scheduled maturity of the 2016 Term Loan on July 21, 2023. On March 29, 2018, we entered into the $250.0 million 2018 Term Loan (see note 6) maturing on July 21, 2023, which increased and replaced the 2016 Term Loan. The interest rate swap arrangements that had effectively fixed the 2016 Term Loan now effectively fix the interest rate on a $150.0 million portion of the 2018 Term Loan at 2.31%. On March 29, 2018, we entered into four interest rate swap arrangements with a total notional amount of $100.0 million to effectively fix the interest rate on the remaining $100.0 million of the 2018 Term Loan at 3.71%, that commenced on June 29, 2018 and extending until the maturity of the 2018 Term Loan on July 21, 2023. The $250.0 million 2018 Term Loan has an all-in fixed interest rate of 2.87% (see note 6 and note 7). In November 2019, we entered into four forward interest rate swap arrangements, each effective as of April 1, 2020 (“Forward Swaps”) with a total notional amount of $200.0 million to reduce our exposure to adverse fluctuations in interest rates on future fixed-rate debt to replace all $250.0 million of our 4.95% 10-year unsecured notes that were scheduled to mature in October 2020. In April 2020, we used borrowings from our Revolving Credit Facility to prepay all $250.0 million of our 4.95% 10-year unsecured notes without penalty. In September 2020, in conjunction with the entry into the note purchase agreement to issue the Green Bonds, we terminated the Forward Swaps. At the time of termination, the Forward Swaps had a liability fair value of $20.4 million, which will be amortized as interest expense over the 10-year term of the Green Bonds. On October 2, 2020, we paid the $20.4 million liability associated with the termination of the Forward Swaps. In December 2020, in connection with the prepayment of our 2015 Term Loan, we terminated interest rate swap agreements with notional amounts in the aggregate of $150.0 million (see note 7). As a result of the termination, the accumulated fair value of the interest rate swaps was reclassified from Accumulated other comprehensive loss to Loss on interest rate derivatives on our consolidated income statements, which resulted in a realized loss of approximately $0.6 million. 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. 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 highly effective for all periods presented. The fair values of the interest rate swaps as of December 31, 2020 and 2019, are as follows (in thousands): Aggregate Effective Date Fair Value Derivative Assets (Liabilities) December 31, Derivative Instrument Maturity Date 2020 2019 Interest rate swaps $ 150,000 October 15, 2015 March 15, 2021 $ — $ (62) Interest rate swaps 150,000 March 31, 2017 July 21, 2023 (4,009) 1,825 Interest rate swaps 100,000 June 29, 2018 July 21, 2023 (6,246) (3,664) Interest rate swaps 200,000 April 1, 2020 April 1, 2030 — 3,724 $ (10,255) $ 1,823 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, as follows (in thousands): Year Ending December 31, 2020 2019 2018 Unrealized (loss) gain on interest rate hedges $ (33,025) $ (8,016) $ 420 Amounts reported in Accumulated other comprehensive income related to derivatives will be reclassified to interest expense as interest payments are made on our variable-rate debt. The gains or losses reclassified from Accumulated other comprehensive income into interest expense for the three years ended December 31, 2020, were as follows (in thousands): Year Ending December 31, 2020 2019 2018 Loss reclassified from Accumulated other comprehensive income (loss) into interest expense $ 79 $ — $ — During the next twelve months, we estimate that $6.0 million will be reclassified as an increase 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, 2020, we did not have any derivatives in an asset position and the fair value of the derivative liabilities, including accrued interest, was $10.3 million. As of December 31, 2020, we have not posted any collateral related to these agreements.

Fair Value Disclosures

Fair Value Disclosures	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Fair Value Disclosures	NOTE 9: 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, 2020 and 2019 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 8). 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, 2020 and 2019 were as follows (in thousands): December 31, 2020 December 31, 2019 Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs Significant Unobservable Inputs Fair Value Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Assets: SERP $ 2,433 $ — $ 2,433 $ — $ 1,792 $ — $ 1,792 $ — Interest rate swaps — — — — 5,549 — 5,549 — Liabilities: Interest rate swaps $ (10,255) $ — $ (10,255) $ — $ (3,726) $ — $ (3,726) $ — 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 models. 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, 2020 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, 2020. 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). 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. Line of credit payable consist of bank facilities which we use for various purposes including working capital, acquisition funding and capital improvements. The line 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, 2020 and 2019, the carrying values and estimated fair values of our financial instruments were as follows (in thousands): December 31, 2020 2019 Carrying Fair Value Carrying Fair Value Cash and cash equivalents $ 7,700 $ 7,700 $ 12,939 $ 12,939 Restricted cash 603 603 1,812 1,812 Mortgage notes payable — — 47,074 47,899 Line of credit payable 42,000 42,000 56,000 56,000 Notes payable 945,370 978,678 996,722 1,022,937

Stock Based Compensation

Stock Based Compensation	12 Months Ended
	Dec. 31, 2020
Share-based Payment Arrangement, Noncash Expense [Abstract]
Stock Based Compensation	NOTE 10: STOCK BASED COMPENSATION WashREIT 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, 2020 and 2019. On February 14, 2020, the board of trustees adopted an Amended and Restated Executive Officer Short-Term Incentive Plan (the “Officer STIP”) and an Amended and Restated Executive Officer Long-Term Incentive Plan (the “Officer LTIP”). Upon adoption by the board of trustees, both plans became effective for the performance periods beginning January 1, 2020. Officer STIP Under the Officer STIP, as revised, all named executive officers will have the opportunity to receive an annual cash bonus based on the achievement of certain performance measures that will be established for each performance period. Each year, the Compensation Committee will establish the threshold, target and high performance goals for each performance measure, as well as the weighting attributable to each such performance measure, with the aggregate weighting for all such performance measures to total 100%. Such performance measures will consist of one or more financial performance measures and, if determined by the Compensation Committee, individual performance measures. Upon or following completion of a performance period, the degree of achievement of each financial performance measure will be determined by the Compensation Committee. The degree of achievement of any individual financial performance measures will be determined by the Compensation Committee in its discretion with respect to the Chief Executive Officer, and by the Chief Executive Officer or other immediate supervisor in his or her discretion with respect to all other participants (subject to final approval by the Compensation Committee), and the Compensation Committee will evaluate the degree of achievement of the individual performance measures on a scale of below 1 (below threshold), 1 (threshold), 2 (target) or 3 (high) or any fractional number between 1 and 3. Each participant’s total award under the Officer STIP with respect to a performance period will be stated as a percentage of the participant’s annual base salary determined as of the first day of that performance period, which percentage will depend upon the participant’s position and the degree of achievement of threshold, target, and high performance goals for the performance period which, except as otherwise determined by the Compensation Committee, will be as set forth in the table below: Threshold Target High President and Chief Executive Officer 63% 125% 188% Executive Vice President 48% 93% 160% Senior Vice President 35% 65% 115% If a Change in Control (as defined in the Officer STIP) occurs during a performance period while the participant is employed, the participant will receive a prorated award under the Officer STIP calculated based on the actual levels of achievement of the prorated performance goals as of the date of the Change in Control. Officer LTIP Under the Officer LTIP, as revised, all named executive officers will have the opportunity to receive awards based on (i) the achievement of performance measures, which will be established for each performance period, and (ii) continued employment with the Company. The aggregate weighting for the performance measures and the time-based measures, as determined by the Compensation Committee, will total 100%. The performance measures will consist of one or more shareholder return measures and one or more strategic measures. The awards earned under the Officer LTIP, if any, are payable in our common shares of beneficial interest. Each participant’s total award under the Officer LTIP with respect to a performance period will be stated as a percentage of the participant’s annual base salary determined as of the beginning of that performance period. The percentage will depend upon the participant’s position and the degree of achievement of threshold, target, and high performance goals for the performance period which, except as otherwise determined by the Compensation Committee, will be as set forth in the table below: Threshold Target High President and Chief Executive Officer 198% 275% 440% Executive Vice President 143% 200% 295% Senior Vice President 100% 143% 207% Any time-based awards under the Officer LTIP will be subject to a three-year vesting schedule, with any award vesting in one-third increments on December 15 of each year of the applicable performance period if the participant remains employed by the Company on each of such dates. The Officer LTIP provides that following a performance period, 100% of any performance-based award will vest immediately upon grant. Each year, the Compensation Committee will establish the threshold, target and high performance goals for each performance measure. Upon or following completion of a performance period, the degree of achievement of each performance measure will be determined by the Compensation Committee in its discretion. If a Change in Control (as defined in the Officer LTIP) occurs during a performance period while the participant is employed, the Officer LTIP provides that all time-based awards which are unvested will become vested, and the participant will receive a pro-rated portion of the shareholder return measure-based awards and the strategic measure-based awards will be calculated at target. Prior Short-Term Incentive Plan ("Prior STIP") Under the Prior STIP, executive officers earned 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 Prior 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. 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. The grant date for the 50% of the Prior STIP award payable in restricted shares was the date on which the Compensation Committee approved the Prior 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 staff are payable 100% in cash. Prior Long-Term Incentive Plan ("Prior LTIP") Under the Prior LTIP, executive officers earned awards payable, 75% in unrestricted shares and 25% in restricted shares, based on a percentage of salary and the achievement of certain market conditions. For performance periods beginning prior to January 1, 2018, performance was 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. During the first quarter of 2018, we amended the Prior LTIP for executive officers to eliminate the absolute TSR component and only utilize relative TSR in the measurement of market condition performance. Under the amended Prior LTIP, relative TSR was evaluated 50% relative to a defined population of peer companies and 50% relative to the FTSE NAREIT Diversified Index. The amendment became effective for three-year performance periods commencing on or after January 1, 2018. The officers' total award opportunities under the Prior LTIP stated as a percentage of base salary ranged 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. 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. For three-year performance periods commencing on or after January 1, 2018, the market condition performance measurement is based on total shareholder return relative to a defined population of peer companies (50% weighting) and relative to the FTSE NAREIT Diversified Index (50% weighting). The model evaluates the awards for changing total shareholder return over the term of the vesting, relative to the peer companies and relative to the FTSE NAREIT Diversified Index, and uses random simulations that are based on past stock characteristics as well as dividend growth and other factors for WashREIT and each of the peer companies. For three-year performance periods commencing prior to January 1, 2018, the market condition performance measurement was based on total shareholder return on an absolute basis (50% weighting) and relative to a defined population of peer companies (50% weighting). The assumptions used to value the TSR portion of the officer LTIP and Prior LTIP awards were as follows: 2020 Awards 2019 Awards 2018 Awards Expected volatility (1) 17.5 % 18.1 % 17.9 % Risk-free interest rate (2) 1.4 % 2.4 % 2.4 % Expected term (3) 3 years 3 and 4 years 3 and 4 years Share price at grant date $31.50 $23.00 $ 26.06 ______________________________ (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 2020 ranged from approximately 20% to 42% for the 50% of the LTIP based on TSR relative to a defined population of peer companies and from 22% to 46% for the 50% of the LTIP based on TSR relative to the FTSE NAREIT Diversified Index. The calculated grant date fair value as a percentage of base salary for the officers for the three-year performance period that commenced in 2019 ranged from approximately 35% to 68% for the 50% of the LTIP based on TSR relative to a defined population of peer companies and from 39% to 74% for the 50% of the LTIP based on TSR relative to the FTSE NAREIT Diversified Index. The calculated grant date fair value as a percentage of base salary for the officers for the three-year performance period that commenced in 2018 ranged from approximately 31% to 60% for the 50% of the LTIP based on TSR relative to a defined population of peer companies and from 35% to 68% for the 50% of the LTIP based on TSR relative to the FTSE NAREIT Diversified Index. During 2017, our chief executive officer was granted a one-time equity award of 100,000 restricted shares. None of the restricted shares vest until the fifth anniversary of the grant date, at which time 100% of the restricted shares will vest, subject to Mr. McDermott's continued employment with WashREIT until such vesting date. Our non-executive officers and other employees earn restricted share unit awards under a long-term incentive plan for non-executive officers and staff 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. 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 WashREIT 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 for each of three years ended December 31, 2020. Total Compensation Expense Total compensation expense recognized in the consolidated financial statements for each of the three years ended December 31, 2020 for all share based awards was $7.9 million, $7.7 million and $6.7 million, respectively, net of capitalized stock-based compensation expense of $0.4 million, $0.2 million and $0.3 million, respectively. Restricted Share Awards with Performance and Service Conditions The activity for the three years ended December 31, 2020 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, 2017 236,694 $ 27.96 Granted 304,087 25.98 Vested during year (224,150) 27.40 Forfeited (5,621) 29.43 Unvested at December 31, 2018 311,010 29.07 Granted 213,782 26.26 Vested during year (236,013) 27.43 Forfeited (19,396) 26.60 Unvested at December 31, 2019 269,383 28.45 Granted 285,101 30.39 Vested during year (239,033) 27.54 Forfeited (8,456) 28.35 Unvested at December 31, 2020 306,995 30.96 The total fair value of share grants vested for each of the three years ended December 31, 2020 was $6.6 million, $6.5 million and $6.1 million, respectively. As of December 31, 2020, the total compensation cost related to non-vested share awards not yet recognized was $7.0 million, which we expect to recognize over a weighted average period of 21 months. Restricted and Unrestricted Shares with Market Conditions Stock based awards with market conditions under the LTIP and Prior LTIP were granted in 2020, 2019 and 2018 with fair market values, as determined using a Monte Carlo simulation, as follows (in thousands): 2020 Awards 2019 Awards 2018 Awards Unrestricted (1) Restricted Unrestricted Restricted Unrestricted Relative Peer TSR $ 510 $ 184 $ 552 $ 203 $ 608 Absolute/Index TSR (2) 565 201 602 230 690 The unamortized value of these awards with market conditions as of December 31, 2020 was as follows (in thousands): 2020 Awards 2019 Awards 2018 Awards Unrestricted Restricted Unrestricted Restricted Unrestricted Relative Peer TSR $ 355 $ 92 $ 184 $ 42 $ — Absolute/Index TSR (1) 393 100 201 48 — ______________________________ (1) The 2020 Awards were granted under the 2020 LTIP, whereby all of the shares vest immediately at the end of the three-year performance period. The 2019 and 2018 Awards were granted under the Prior LTIP, whereby the unrestricted shares (75%) vest immediately at the end of the three-year performance period and the restricted shares (25%) vest over a one-year period commencing on the January 1 following the end of the three-year performance period.

Other Benefit Plans

Other Benefit Plans	12 Months Ended
	Dec. 31, 2020
Retirement Benefits [Abstract]
Other Benefit Plans	NOTE 11: 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 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, 2020, we made contributions to the 401(k) plan of $0.4 million, $0.5 million and $0.5 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 WashREIT. The deferred compensation liability was $0.7 million and $0.9 million at December 31, 2020 and 2019, respectively.

Earnings Per Common Share

Earnings Per Common Share	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Earnings per Common Share	NOTE 12: 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 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 operating partnership units under the if-converted 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, 2020 was as follows (in thousands, except per share data): Year Ended December 31, 2020 2019 2018 Numerator: (Loss) income from continuing operations $ (15,680) $ 29,132 $ 1,153 Allocation of distributed earnings to unvested restricted share awards to continuing operations (545) (125) (526) Adjusted (loss) income from continuing operations (16,225) 29,007 627 Income from discontinued operations, including gain on sale of real estate — 354,418 24,477 Allocation of earnings from discontinued operations to unvested restricted share awards — (1,837) — Adjusted income from discontinued operations — 352,581 24,477 Adjusted net (loss) income $ (16,225) $ 381,588 $ 25,104 Denominator: Weighted average shares outstanding – basic 82,348 80,257 78,960 Effect of dilutive securities: Operating partnership units — 12 12 Employee restricted share awards — 66 70 Weighted average shares outstanding – diluted 82,348 80,335 79,042 Earnings per common share, basic: Continuing operations $ (0.20) $ 0.36 $ 0.01 Discontinued operations — 4.39 0.31 Basic net (loss) income per common share $ (0.20) $ 4.75 $ 0.32 Earnings per common share, diluted: Continuing operations $ (0.20) $ 0.36 $ 0.01 Discontinued operations — 4.39 0.31 Diluted net (loss) income per common share $ (0.20) $ 4.75 $ 0.32 Dividends declared per common share $ 1.20 $ 1.20 $ 1.20

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	NOTE 13: COMMITMENTS AND CONTINGENCIES Development Commitments At December 31, 2020, 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, 2020
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Segment Information	NOTE 14: SEGMENT INFORMATION We evaluate real estate performance and allocate resources by property type through two reportable segments: office and multifamily. 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. We have eight retail properties that do not meet the qualitative or quantitative criteria for a reportable segment and are classified as “Corporate and other” in our segment disclosure tables. We evaluate performance based upon net operating income of 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 each segment’s performance. Net operating income is a key measurement of our segment profit and loss and is defined as real estate rental revenue less real estate expenses. Real estate rental revenue as a percentage of the total for each of the reportable operating segments for the three years ended December 31, 2020 was as follows: Year Ended December 31, 2020 2019 2018 Multifamily 49 % 41 % 33 % Office 45 % 53 % 61 % Corporate and other 6 % 6 % 6 % The percentage of income producing real estate assets classified as held and used, at cost, for each of the reportable operating segments as of December 31, 2020 and 2019 was as follows: December 31, 2020 2019 Multifamily 54 % 50 % Office 41 % 45 % Corporate and other 5 % 5 % The accounting policies of each of the segments are the same as those described in note 2. The following tables present revenues, net operating income, capital expenditures and total assets for the three years ended December 31, 2020 from these segments, and reconciles net operating income of reportable segments to net (loss) income as reported (in thousands): Year Ended December 31, 2020 Office Multifamily Corporate (1) Consolidated Real estate rental revenue $ 132,327 $ 145,045 $ 16,746 $ 294,118 Real estate expenses 49,452 58,115 5,342 112,909 Net operating income $ 82,875 $ 86,930 $ 11,404 $ 181,209 Depreciation and amortization (120,030) General and administrative (23,951) Interest expense (37,305) Loss on interest rate derivatives (560) Loss on extinguishment of debt (34) Loss on sale of real estate (15,009) Net loss $ (15,680) Capital expenditures $ 31,148 $ 24,675 $ 2,494 $ 58,317 Total assets $ 940,069 $ 1,333,235 $ 136,514 $ 2,409,818 Year Ended December 31, 2019 Office Multifamily Corporate and Other (1) Consolidated Real estate rental revenue $ 164,059 $ 126,131 $ 18,990 $ 309,180 Real estate expenses 60,923 49,135 5,522 115,580 Net operating income $ 103,136 $ 76,996 $ 13,468 $ 193,600 Depreciation and amortization (136,253) General and administrative (26,068) Real estate impairment (8,374) Interest expense (53,734) Gain on sale of real estate 59,961 Discontinued operations: Income from properties sold or held for sale 16,158 Gain on sale of real estate 339,024 Loss on extinguishment of debt (764) Net income $ 383,550 Capital expenditures $ 38,634 $ 25,779 $ 4,534 $ 68,947 Total assets $ 1,134,147 $ 1,340,634 $ 153,547 $ 2,628,328 Year Ended December 31, 2018 Office Multifamily Corporate and Other (1) Consolidated Real estate rental revenue $ 178,474 95,194 18,062 $ 291,730 Real estate expenses 63,321 37,235 5,036 105,592 Net operating income $ 115,153 $ 57,959 $ 13,026 $ 186,138 Depreciation and amortization (111,826) General and administrative (22,089) Interest expense (50,501) Real estate impairment (1,886) Loss on extinguishment of debt (1,178) Gain on sale of real estate 2,495 Discontinued operations: Income from properties sold or held for sale 24,477 Net income $ 25,630 Capital expenditures $ 42,019 $ 25,117 $ 4,897 $ 72,033 Total assets $ 1,248,673 $ 792,170 $ 376,261 $ 2,417,104 ______________________________ (1) Includes the retail properties not classified as discontinued operations: Takoma Park, Westminster, Concord Centre, Chevy Chase Metro Plaza, 800 S. Washington Street, Randolph Shopping Center, Montrose Shopping Center and Spring Valley Village, and total assets and capital expenditures include all retail properties, including those classified as discontinued operations.

Selected Quarterly Financial Da

Selected Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
Selected Quarterly Financial Data (Unaudited)	NOTE 15: SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED) Unaudited financial data by quarter in each of the years ended December 31, 2020 and 2019 were as follows (in thousands, except for per share data): Quarter (1), (2) First Second Third Fourth 2020 Real estate rental revenue $ 76,792 $ 72,870 $ 73,227 $ 71,229 Income (loss) from continuing operations $ 1,719 $ (5,406) $ (956) $ (11,037) Net income (loss) $ 1,719 $ (5,406) $ (956) $ (11,037) Income (loss) from continuing operations per share Basic $ 0.02 $ (0.07) $ (0.01) $ (0.13) Diluted $ 0.02 $ (0.07) $ (0.01) $ (0.13) Net income (loss) per share Basic $ 0.02 $ (0.07) $ (0.01) $ (0.13) Diluted $ 0.02 $ (0.07) $ (0.01) $ (0.13) 2019 Real estate rental revenue $ 71,434 $ 76,820 $ 80,259 $ 80,667 (Loss) income from continuing operations $ (10,443) $ (6,191) $ (8,432) $ 54,198 Net (loss) income $ (4,405) $ 987 $ 332,770 $ 54,198 (Loss) income from continuing operations per share Basic $ (0.13) $ (0.08) $ (0.10) $ 0.66 Diluted $ (0.13) $ (0.08) $ (0.10) $ 0.66 Net (loss) income per share Basic $ (0.06) $ 0.01 $ 4.14 $ 0.66 Diluted $ (0.06) $ 0.01 $ 4.14 $ 0.66 ______________________________ (1) With regard to per share calculations, the sum of the quarterly results may not equal full year results due to rounding.

Shareholders' Equity

Shareholders' Equity	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
Shareholders' Equity	NOTE 16: SHAREHOLDERS' EQUITY On May 4, 2018, we entered into eight separate equity distribution agreements (collectively, the “2018 Equity Distribution Agreements”) with each of Wells Fargo Securities, LLC, BNY Mellon Capital Markets, LLC, Capital One Securities, Inc., Citigroup Global Markets Inc., Goldman Sachs & Co. LLC, J.P. Morgan Securities LLC, KeyBanc Capital Markets Inc. and Truist Securities Inc., (f/k/a SunTrust Robinson Humphrey, Inc.) relating to the issuance of up to $250.0 million of our common shares from time to time under our at-the-market program. Issuances of our common shares are made at market prices prevailing at the time of issuance. We may use net proceeds from the issuance of common shares under this program for general business purposes, including, without limitation, working capital, the acquisition, renovation, expansion, improvement, development or redevelopment of income producing properties or the repayment of debt. Our issuances and net proceeds on the 2018 Equity Distribution Agreements for the three years ended December 31, 2020 were as follows (in thousands, except per share data): Year Ended December 31, 2020 2019 2018 Issuance of common shares 2,000 1,859 1,165 Weighted average price per share $ 23.86 $ 30.00 $ 31.18 Net proceeds $ 48,355 $ 54,916 $ 35,472 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. Our issuances and net proceeds on the dividend reinvestment program for the three years ended December 31, 2020 were as follows (in thousands, except per share data): Year Ended December 31, 2020 2019 2018 Issuance of common shares 89 173 81 Weighted average price per share $ 24.12 $ 27.58 $ 29.18 Net proceeds $ 2,121 $ 4,755 $ 1,973

Deferred Costs

Deferred Costs	12 Months Ended
	Dec. 31, 2020
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Deferred Costs	NOTE 17: DEFERRED COSTS As of December 31, 2020 and 2019, deferred leasing costs and deferred leasing incentives were included in prepaid expenses and other assets as follows (in thousands): December 31, 2020 2019 Gross Carrying Accumulated Net Gross Carrying Accumulated Net Deferred leasing costs $ 55,736 $ 30,700 $ 25,036 $ 60,900 $ 29,580 $ 31,320 Deferred leasing incentives 22,942 18,076 4,866 18,926 11,133 7,793 Amortization, including write-offs, of deferred leasing costs and deferred leasing incentives for the three years ended December 31, 2020 were as follows (in thousands): Year Ended December 31, 2020 2019 2018 Deferred leasing costs amortization $ 5,389 $ 6,599 $ 5,881 Deferred leasing incentives amortization 2,070 2,862 2,811

Schedule II Valuation and Quali

Schedule II Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2020
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Schedule II Valuation and Qualifying Accounts	SCHEDULE II VALUATION AND QUALIFYING ACCOUNTS FOR THE YEARS ENDED December 31, 2020, 2019 AND 2018 (IN THOUSANDS) Balance at Beginning of Year Additions Charged to Expenses Net Recoveries Balance at End of Year Valuation allowance for deferred tax assets 2020 $ 1,402 $ — $ — $ 1,402 2019 $ 1,419 $ — $ (17) $ 1,402 2018 $ 1,413 $ 6 $ — $ 1,419

Schedule III Real Estate and Ac

Schedule III Real Estate and Accumulated Depreciation	12 Months Ended
	Dec. 31, 2020
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation Disclosure [Abstract]
Schedule III Real Estate and Accumulated Depreciation	SCHEDULE III Initial Cost (a) Net Improvements (Retirement) since Acquisition Gross Amounts at Which Carried at December 31, 2020 Accumulated Depreciation at December 31, 2020 Properties Location Land Buildings and Improvements Land Buildings and Improvements Total (b) Year of Construction Date of Acquisition Net Units Depreciation Life (c) Multifamily Properties 3801 Connecticut Avenue Washington, D.C. $ 420,000 $ 2,678,000 $ 20,399,000 $ 420,000 $ 23,077,000 $ 23,497,000 $ 14,646,000 1951 Jan 1963 178,000 307 30 years Roosevelt Towers Virginia 336,000 1,996,000 13,915,000 336,000 15,911,000 16,247,000 12,104,000 1964 May 1965 170,000 191 40 years Park Adams Virginia 287,000 1,654,000 14,053,000 287,000 15,707,000 15,994,000 11,776,000 1959 Jan 1969 173,000 200 35 years The Ashby at McLean (e) Virginia 4,356,000 17,102,000 28,435,000 4,356,000 45,537,000 49,893,000 30,928,000 1982 Aug 1996 274,000 256 30 years Bethesda Hill Apartments Maryland 3,900,000 13,412,000 16,664,000 3,900,000 30,076,000 33,976,000 22,059,000 1986 Nov 1997 225,000 195 30 years Bennett Park Virginia 2,861,000 917,000 82,514,000 4,774,000 81,518,000 86,292,000 43,271,000 2007 Feb 2001 215,000 224 28 years The Clayborne Virginia 269,000 — 31,574,000 699,000 31,144,000 31,843,000 17,936,000 2008 Jun 2003 60,000 74 26 years The Kenmore Washington, D.C. 28,222,000 33,955,000 19,618,000 28,222,000 53,573,000 81,795,000 19,891,000 1948 Sep 2008 268,000 374 30 years The Maxwell Virginia 12,787,000 — 38,240,000 12,848,000 38,179,000 51,027,000 12,541,000 2014 Jun 2011 116,000 163 30 years Yale West Washington, D.C. 14,684,000 62,069,000 1,775,000 14,684,000 63,844,000 78,528,000 15,728,000 2011 Feb 2014 173,000 216 30 years The Paramount (e) Virginia 8,568,000 38,716,000 3,512,000 8,568,000 42,228,000 50,796,000 12,922,000 1984 Oct 2013 141,000 135 30 years The Wellington Virginia 30,548,000 116,563,000 17,815,000 30,548,000 134,378,000 164,926,000 27,667,000 1960 Jul 2015 600,000 711 30 years Trove (d) Virginia 15,000,000 — 117,215,000 15,000,000 117,215,000 132,215,000 3,261,000 2020 Jul 2015 293,000 401 30 years Riverside Apartments Virginia 38,924,000 184,854,000 40,324,000 38,924,000 225,178,000 264,102,000 40,760,000 1971 May 2016 1,001,000 1,222 30 years Riverside Apartments land parcel (d) Virginia 15,968,000 — 12,658,000 — 28,626,000 28,626,000 — n/a May 2016 — n/a n/a Assembly Alexandria Virginia 23,942,000 93,672,000 5,501,000 23,942,000 99,173,000 123,115,000 6,474,000 1990 Jun 2019 437,000 532 30 years Assembly Manassas Virginia 13,586,000 68,802,000 1,741,000 13,586,000 70,543,000 84,129,000 4,975,000 1986 Jun 2019 390,000 408 30 years Assembly Dulles Virginia 12,476,000 66,852,000 1,964,000 12,476,000 68,816,000 81,292,000 4,723,000 2000 Jun 2019 361,000 328 30 years Assembly Leesburg Virginia 4,113,000 21,286,000 387,000 4,113,000 21,673,000 25,786,000 1,679,000 1986 Jun 2019 124,000 134 30 years Assembly Herndon Virginia 11,225,000 51,534,000 4,023,000 11,225,000 55,557,000 66,782,000 3,984,000 1991 Jun 2019 221,000 283 30 years Assembly Germantown Maryland 7,609,000 34,431,000 1,193,000 7,609,000 35,624,000 43,233,000 2,566,000 1990 Jun 2019 211,000 218 30 years Assembly Watkins Mill Maryland 7,151,000 30,851,000 636,000 7,151,000 31,487,000 38,638,000 2,207,000 1975 Jun 2019 193,000 210 30 years Cascade at Landmark Virginia 12,289,000 56,235,000 1,322,000 12,289,000 57,557,000 69,846,000 3,627,000 1988 Jun 2019 273,000 277 30 years $ 269,521,000 $ 897,579,000 $ 475,478,000 $ 255,957,000 $ 1,386,621,000 $ 1,642,578,000 $ 315,725,000 6,097,000 7,059 Office Buildings 1901 Pennsylvania Avenue Washington, D.C. $ 892,000 $ 3,481,000 $ 21,602,000 $ 892,000 $ 25,083,000 $ 25,975,000 $ 19,521,000 1960 May 1977 101,000 28 years 515 King Street Virginia 4,102,000 3,931,000 9,319,000 4,102,000 13,250,000 17,352,000 7,709,000 1966 Jul 1992 75,000 50 years 1220 19th Street Washington, D.C. 7,803,000 11,366,000 18,609,000 7,803,000 29,975,000 37,778,000 20,087,000 1976 Nov 1995 103,000 30 years 1600 Wilson Boulevard Virginia 6,661,000 16,742,000 31,803,000 6,661,000 48,545,000 55,206,000 31,854,000 1973 Oct 1997 171,000 30 years Silverline Center (e) Virginia 12,049,000 71,825,000 104,041,000 12,049,000 175,866,000 187,915,000 112,929,000 1972 Nov 1997 552,000 30 years Courthouse Square Virginia — 17,096,000 10,248,000 — 27,344,000 27,344,000 18,712,000 1979 Oct 2000 121,000 30 years 2000 M Street Washington, D.C. — 61,101,000 42,983,000 — 104,084,000 104,084,000 44,470,000 1971 Dec 2007 233,000 30 years 1140 Connecticut Avenue Washington, D.C. 25,226,000 50,495,000 19,800,000 25,226,000 70,295,000 95,521,000 27,200,000 1966 Jan 2011 184,000 30 years Fairgate at Ballston Virginia 17,750,000 29,885,000 8,289,000 17,750,000 38,174,000 55,924,000 14,375,000 1988 Jun 2012 144,000 30 years Army Navy Building Washington, D.C. 30,796,000 39,315,000 13,116,000 30,796,000 52,431,000 83,227,000 15,831,000 1912 Mar 2014 108,000 30 years 1775 Eye Street, NW Washington, D.C. 48,086,000 51,074,000 20,742,000 48,086,000 71,816,000 119,902,000 20,606,000 1964 May 2014 189,000 30 years Watergate 600 Washington, D.C. 45,981,000 78,325,000 43,902,000 45,751,000 122,457,000 168,208,000 19,068,000 1972 Apr 2017 294,000 30 years Arlington Tower Virginia 63,970,000 156,525,000 16,028,000 63,970,000 172,553,000 236,523,000 22,178,000 1980 Jan 2018 390,000 30 years $ 263,316,000 $ 591,161,000 $ 360,482,000 $ 263,086,000 $ 951,873,000 $ 1,214,959,000 $ 374,540,000 2,665,000 Initial Cost (a) Net Improvements (Retirement) since Acquisition Gross Amounts at Which Carried at December 31, 2020 Accumulated Depreciation at December 31, 2020 Properties Location Land Buildings Land Buildings Total (b) Year of Date of Acquisition Net Units Depreciation Retail Centers Westminster Maryland $ 519,000 $ 1,775,000 $ 10,022,000 $ 519,000 $ 11,797,000 $ 12,316,000 $ 8,938,000 1969 Sep 1972 150,000 37 years Concord Centre Virginia 413,000 850,000 7,628,000 413,000 8,478,000 8,891,000 4,353,000 1960 Dec 1973 75,000 33 years Takoma Park (e) Maryland 415,000 1,084,000 302,000 366,000 1,435,000 1,801,000 1,210,000 1962 Jul 1963 51,000 50 years Chevy Chase Metro Plaza Washington, D.C. 1,549,000 4,304,000 8,438,000 1,549,000 12,742,000 14,291,000 8,743,000 1975 Sep 1985 49,000 50 years 800 S. Washington Street Virginia 2,904,000 5,489,000 6,154,000 2,904,000 11,643,000 14,547,000 6,562,000 1955 Jun 1998 46,000 30 years Randolph Shopping Center Maryland 4,928,000 13,025,000 1,436,000 4,928,000 14,461,000 19,389,000 7,369,000 1972 May 2006 83,000 30 years Montrose Shopping Center (e) Maryland 11,612,000 22,410,000 2,604,000 11,020,000 25,606,000 36,626,000 12,723,000 1970 May 2006 151,000 30 years Spring Valley Village Washington, D.C. 10,836,000 32,238,000 12,760,000 10,836,000 44,998,000 55,834,000 8,851,000 1941 Oct 2014 94,000 30 years $ 33,176,000 $ 81,175,000 $ 49,344,000 $ 32,535,000 $ 131,160,000 $ 163,695,000 $ 58,749,000 699,000 Total $ 566,013,000 $ 1,569,915,000 $ 885,304,000 $ 551,578,000 $ 2,469,654,000 $ 3,021,232,000 $ 749,014,000 9,461,000 7,059 ______________________________ a) 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. b) At December 31, 2020, total land, buildings and improvements are carried at $1,920.0 million for federal income tax purposes. c) The useful life shown is for the main structure. Buildings and improvements are depreciated over various useful lives ranging from 3 to 50 years. d) As of December 31, 2020, WashREIT had under development multifamily properties, Trove and Riverside Apartments land parcel. The value not yet placed into service at December 31, 2020 was $7.1 million and $28.6 million, respectively. e) As of December 31, 2020, WashREIT had investments in various development, redevelopment and renovation projects, including The Ashby at McLean, Montrose Shopping Center, Silverline Center, Takoma Park and The Paramount. The total value of these projects, which has not yet been placed in service, is $1.9 million at December 31, 2020. The following is a reconciliation of real estate assets and accumulated depreciation for the three years ended December 31, 2020 (in thousands): Year Ended December 31, 2020 2019 2018 Real estate assets Balance, beginning of period $ 3,159,463 $ 2,973,816 $ 2,831,683 Additions: Property acquisitions (1) — 516,054 220,495 Improvements (1) 81,119 140,109 103,404 Deductions: Impairment write-down — (24,432) (2,177) Write-off of disposed assets (1,694) (7,430) (2,132) Property sales (217,656) (438,654) (177,457) Balance, end of period $ 3,021,232 $ 3,159,463 $ 2,973,816 Accumulated depreciation Balance, beginning of period $ 712,630 $ 770,535 $ 690,417 Additions: Depreciation 106,920 107,938 98,141 Deductions: Impairment write-down — (16,058) (291) Write-off of disposed assets (730) (2,173) (1,859) Property sales (69,806) (147,612) (15,873) Balance, end of period $ 749,014 $ 712,630 $ 770,535 ______________________________ (1) Includes non-cash accruals for capital items.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies and Basis of Presentation (Policies)	12 Months Ended
	Dec. 31, 2020
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 WashREIT and our subsidiaries and entities in which WashREIT has a controlling financial interest. All intercompany balances and transactions have been eliminated in consolidation.
Use of Estimates in the Financial Statements	Use of Estimates in the Financial StatementsThe 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 Standards Standards Adopted Standard/Description Effective Date and Adoption Considerations Effect on Financial Statements or Other significant Matters ASU 2016-13, Measurement of Credit Losses on Financial Instruments . This standard requires financial assets measured at an amortized cost basis, including trade receivables, to be presented at the net amount expected to be collected. This standard does not apply to receivables arising from operating leases accounted for in accordance with Topic 842. We adopted the new standard as of January 1, 2020. The adoption of the new standard did not have a material impact on our consolidated financial statements. ASU 2018-15, Intangibles - Goodwill and Other - Internal-Use Software . This standard requires a customer in a cloud computing arrangement that is a service contract to follow the internal-use software guidance to determine which implementation costs to capitalize as assets. We adopted the new standard as of January 1, 2020. The adoption of the new standard did not have a material impact on our consolidated financial statements. Standard/Description Effective Date and Adoption Considerations Effect on Financial Statements or Other significant Matters ASU 2020-04, Reference Rate Reform - Facilitation of the Effects of Reference Rate Reform on Financial Reporting . This standard contains optional practical expedients and exceptions for applying Generally Accepted Accounting Principles (“GAAP”) to contracts, hedging relations, and other transactions affected by reference rate reform if certain criteria are met. We elected certain optional practical expedients as of January 1, 2020. The guidance in ASU 2020-04 is optional and may be elected over time as reference rate reform activities occur. As of January 1, 2020, we have elected to apply the hedge accounting expedients related to probability and the assessments of effectiveness for future LIBOR-indexed cash flows to assume that the index upon which future hedged transactions will be based matches the index on the corresponding derivatives. Application of these expedients preserves the presentation of derivatives consistent with past presentation. We continue to evaluate the impact of the guidance and may apply other elections as applicable as additional changes in the market occur.
COVID-19 Lease Modification Accounting Relief	COVID-19 Lease Modification Accounting Relief In April 2020, the Financial Accounting Standards Board (“FASB”) staff issued a question-and-answer document (“Q&A”) that addresses their belief that the guidance on lease modifications in GAAP does not contemplate concessions being executed as rapidly as they were executed as a result of the major financial crisis arising from the COVID-19 pandemic. Under ASC 842, Leases
Revenue Recognition	Revenue Recognition We lease multifamily properties under operating leases with terms of generally one year or less. We lease commercial properties 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. In certain commercial leases, variable lease income, such as percentage rent, is recognized when rents are earned. We recognize rental income and rental abatements from our multifamily and commercial leases on a straight-line basis over the lease term. Recognition of rental income commences when control of the leased space has been transferred to the tenant. We recognize gains on sales of real estate when we have executed a contract for sale of the asset, transferred controlling financial interest in the asset to the buyer and determined that it is probable that we will collect substantially all of the consideration for the asset. Our real estate sale transactions typically meet these criteria at closing. 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 monthly parking revenues as earned. We recognize transient parking revenue when our performance obligation is met.
Rents and Other Receivables	Rents and Other Receivables Lease related receivables, which include contractual amounts accrued and unpaid from tenants and accrued straight-line rents receivable, are reduced for credit losses. Such amounts are recognized as a reduction to real estate rental revenues. We evaluate the collectability of lease receivables monthly using several factors including a lessee’s creditworthiness. We recognize the credit loss on lease related receivables when, in the opinion of management, collection of substantially all lease payments is not probable. When collectability is determined not probable, any lease income recognized subsequent to recognizing the credit loss is limited to the lesser of the lease income reflected on a straight-line basis or cash collected. The adoption of ASU 2016-02
Debt Issuance Costs	Debt Issuance CostsWe 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 direct and incremental 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 operations. 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.
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 40 years. We also capitalize costs incurred in connection with our development projects, including 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 begins when the activities and related expenditures commence and ceases when the project is substantially complete and ready for its intended use, at which time the project is placed into 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 $103.4 million, $101.7 million and $82.9 million during the years ended December 31, 2020, 2019 and 2018, respectively. We charge maintenance and repair costs that do not extend an asset’s useful life to expense as incurred. Interest expense from continuing operations and interest capitalized to real estate assets related to development and major renovation activities for the three years ended December 31, 2020 were as follows (in thousands): Year Ended December 31, 2020 2019 2018 Total interest incurred $ 39,524 $ 56,948 $ 52,592 Capitalized interest (2,219) (3,214) (2,091) Interest expense, net of capitalized interest $ 37,305 $ 53,734 $ 50,501 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. Estimates of undiscounted cash flows are based on forward-looking assumptions, including annual and residual cash flows and our estimated holding period for each property. Such assumptions involve a high degree of judgment and could be affected by future economic and market conditions. When determining if a property has indicators of impairment, we evaluate the property's occupancy, our expected holding period for the property, strategic decisions regarding the property's future operations or development and other market factors. 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. Acquisitions The properties we acquire typically are not businesses as defined by ASU 2017-01, Business Combinations (Topic 805) - Clarifying the Definition of a Business . Per this definition, 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. We therefore account for such acquisitions as asset acquisitions. Acquisition costs are capitalized and identifiable assets (including physical assets and in-place leases), liabilities assumed and any noncontrolling interests are measured by allocating the cost of the acquisition on a relative fair value basis. Acquisitions executed prior to our adoption of ASU 2017-01 as of January 1, 2017 were accounted for as business combinations. 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 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, 2020 and 2019. 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 prior to the expiration date, 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.
Software Developed for Internal Use	Software Developed for Internal Use The costs of software developed for internal use that qualify for capitalization are included with Prepaid expenses and other assets on our consolidated balance sheets. These capitalized costs include external direct costs utilized in developing or obtaining the applications and expenses for employees who are directly associated with the development of the applications. Capitalization of such costs begins when the preliminary project stage is complete and continues until the project is substantially complete and is ready for its intended purpose. Completed projects are amortized on a straight-line basis over their estimated useful lives.
Held for Sale and Discontinued Operations	Held for Sale and Discontinued Operations We classify properties as held for sale when they meet the necessary criteria, which include: (a) senior management commits to a plan to sell the assets; (b) the assets are available for immediate sale in their present condition subject only to terms that are usual and customary for sales of such assets; (c) an active program to locate a buyer and other actions required to complete the plan to sell the assets has been initiated; (d) the sale of the assets is probable and transfer of the assets is expected to qualify for
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 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.
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. We account for forfeitures as they occur. 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
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, 2020 and 2019, 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 2017 through 2019 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 expenses.
Derivatives	DerivativesWe 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 the 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 its creditworthiness. 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, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Properties Sold	During the three years ended December 31, 2020, we sold our interests in the following properties (in thousands): Disposition Date Property Type (Loss) Gain on Sale April 21, 2020 John Marshall II Office $ (6,855) December 2, 2020 Monument II Office $ (8,595) December 17, 2020 1227 25th Street Office 1,125 Total 2020 $ (14,325) June 26, 2019 Quantico Corporate Center (1) Office $ (1,046) July 23, 2019 Shopping Center Portfolio (2) Retail 333,023 August 21, 2019 Frederick Crossing and Frederick County Square Retail 9,507 August 27, 2019 Centre at Hagerstown Retail (3,506) December 19, 2019 1776 G Street Office 61,007 Total 2019 $ 398,985 January 19, 2018 Braddock Metro Center Office $ — June 28, 2018 2445 M Street Office 2,495 Total 2018 $ 2,495 ______________________________ (1) Consists of 925 and 1000 Corporate Drive.
Schedule of Breakdown of Taxable Percentage of Dividends	The following is a breakdown of the taxable percentage of our dividends for the three years ended December 31, 2020, 2019 and 2018 (unaudited): 2020 2019 2018 Ordinary income/Section 199A dividends 36 % 80 % 29 % Return of capital 64 % 20 % 71 % Qualified dividends — % — % — % Unrecaptured Section 1250 gain — % — % — % Capital gain — % — % — %

Summary of Significant Accoun_3

Summary of Significant Accounting Policies and Basis of Presentation (Tables)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Schedule of Recent Accounting Standards	Recent Accounting Standards Standards Adopted Standard/Description Effective Date and Adoption Considerations Effect on Financial Statements or Other significant Matters ASU 2016-13, Measurement of Credit Losses on Financial Instruments . This standard requires financial assets measured at an amortized cost basis, including trade receivables, to be presented at the net amount expected to be collected. This standard does not apply to receivables arising from operating leases accounted for in accordance with Topic 842. We adopted the new standard as of January 1, 2020. The adoption of the new standard did not have a material impact on our consolidated financial statements. ASU 2018-15, Intangibles - Goodwill and Other - Internal-Use Software . This standard requires a customer in a cloud computing arrangement that is a service contract to follow the internal-use software guidance to determine which implementation costs to capitalize as assets. We adopted the new standard as of January 1, 2020. The adoption of the new standard did not have a material impact on our consolidated financial statements. Standard/Description Effective Date and Adoption Considerations Effect on Financial Statements or Other significant Matters ASU 2020-04, Reference Rate Reform - Facilitation of the Effects of Reference Rate Reform on Financial Reporting . This standard contains optional practical expedients and exceptions for applying Generally Accepted Accounting Principles (“GAAP”) to contracts, hedging relations, and other transactions affected by reference rate reform if certain criteria are met. We elected certain optional practical expedients as of January 1, 2020. The guidance in ASU 2020-04 is optional and may be elected over time as reference rate reform activities occur. As of January 1, 2020, we have elected to apply the hedge accounting expedients related to probability and the assessments of effectiveness for future LIBOR-indexed cash flows to assume that the index upon which future hedged transactions will be based matches the index on the corresponding derivatives. Application of these expedients preserves the presentation of derivatives consistent with past presentation. We continue to evaluate the impact of the guidance and may apply other elections as applicable as additional changes in the market occur.
Schedule of Interest and Interest Capitalized	Interest expense from continuing operations and interest capitalized to real estate assets related to development and major renovation activities for the three years ended December 31, 2020 were as follows (in thousands): Year Ended December 31, 2020 2019 2018 Total interest incurred $ 39,524 $ 56,948 $ 52,592 Capitalized interest (2,219) (3,214) (2,091) Interest expense, net of capitalized interest $ 37,305 $ 53,734 $ 50,501

Real Estate (Tables)

Real Estate (Tables)	12 Months Ended
	Dec. 31, 2020
Real Estate [Abstract]
Schedule of Real Estate Investment Portfolio	As of December 31, 2020 and 2019, our real estate investment portfolio classified as income producing property that is held and used, at cost, consists of properties valued as follows (in thousands): December 31, 2020 2019 Multifamily $ 1,606,085 $ 1,469,011 Office 1,214,481 1,329,722 Other 163,051 160,489 $ 2,983,617 $ 2,959,222
Schedule of Costs of Real Estate Portfolio Under Development of Held for Future Development	The cost of our real estate portfolio under development or held for future development as of December 31, 2020 and 2019 is as follows (in thousands): December 31, 2020 2019 Multifamily $ 36,493 $ 123,071 Office 478 478 Other 644 644 $ 37,615 $ 124,193
Schedule of Real Estate Properties and Land Acquired	Properties and land for development acquired during the three years ended December 31, 2020 were as follows: Acquisition Date Property Type # of units (unaudited) Rentable Contract April 30, 2019 Assembly Portfolio - Virginia (1) Multifamily 1,685 N/A $ 379,100 June 27, 2019 Assembly Portfolio - Maryland (2) Multifamily 428 N/A 82,070 July 23, 2019 Cascade at Landmark Multifamily 277 N/A 69,750 2,390 $ 530,920 January 18, 2018 Arlington Tower Office N/A 391,000 $ 250,000 ______________________________ (1) Consists of Assembly Alexandria, Assembly Manassas, Assembly Dulles, Assembly Leesburg and Assembly Herndon. (2) Consists of Assembly Germantown and Assembly Watkins Mill. The Assembly Portfolio - Virginia and Assembly Portfolio - Maryland properties are collectively the “Assembly Portfolio.”
Schedule of Revenue and Earnings from Acquired Operating Properties	The revenue and earnings of our acquisitions during their year of acquisition for the two years ended December 31, 2019 are as follows (in thousands): Year Ended December 31, 2019 2018 Real estate rental revenue $ 27,641 $ 22,389 Net (loss) income (10,167) 3,623
Schedule of Recorded Cost of Asset Acquisitions	We recorded the total cost of the above acquisitions as follows (in thousands): 2019 2018 Land $ 92,391 $ 63,970 Buildings and improvements 423,663 142,900 Tenant origination costs — 13,625 Leasing commissions/absorption costs 15,474 27,465 Net lease intangible assets — 3,142 Net lease intangible liabilities — (545) Total $ 531,528 $ 250,557
Schedule of 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, 2020 and 2019 were as follows (in thousands): December 31, 2020 2019 Gross Carrying Value Accumulated Amortization Net Gross Carrying Value Accumulated Amortization Net Tenant origination costs $ 43,536 $ 30,096 $ 13,440 $ 50,155 $ 33,364 $ 16,791 Leasing commissions/absorption costs 107,102 83,588 23,514 122,348 92,401 29,947 Net lease intangible assets 11,595 9,390 2,205 15,183 11,964 3,219 Net lease intangible liabilities 27,809 20,247 7,562 29,836 20,854 8,982 Below-market ground lease intangible asset 12,080 2,472 9,608 12,080 2,282 9,798 Amortization of these combined components during the three years ended December 31, 2020, 2019 and 2018 was as follows (in thousands): Year Ended December 31, 2020 2019 2018 Depreciation and amortization expense $ 9,997 $ 27,123 $ 22,361 Real estate rental revenue increase, net (406) (924) (1,225) $ 9,591 $ 26,199 $ 21,136
Schedule of Future Amortization of Components of Fair Value of In-Place Leases	Amortization of these combined components over the next five years and thereafter is projected to be as follows (in thousands): Depreciation and amortization expense Real estate rental revenue, net increase Total 2021 $ 8,576 $ (547) $ 8,029 2022 8,078 (736) 7,342 2023 6,032 (974) 5,058 2024 5,264 (862) 4,402 2025 4,231 (777) 3,454 Thereafter 14,380 (1,460) 12,920
Schedule of Properties Held-for-Sale or Sold and Discontinued Operations	We classified as held for sale or sold our interests in the following properties during the three years ended December 31, 2020: Disposition Date Property Type # of units (unaudited) Rentable Contract (Loss) Gain on Sale April 21, 2020 John Marshall II Office N/A 223,000 $ 57,000 $ (6,855) December 2, 2020 Monument II Office N/A 207,000 53,000 (8,595) December 17, 2020 1227 25th Street Office N/A 135,000 53,500 1,125 Total 2020 565,000 $ 163,500 $ (14,325) June 26, 2019 Quantico Corporate Center (1) Office N/A 272,000 $ 33,000 $ (1,046) July 23, 2019 Shopping Center Portfolio (2) Retail N/A 800,000 485,250 333,023 August 21, 2019 Frederick Crossing and Frederick County Square Retail N/A 520,000 57,500 9,507 August 27, 2019 Centre at Hagerstown Retail N/A 330,000 23,500 (3,506) December 19, 2019 1776 G Street Office N/A 262,000 129,500 61,007 Total 2019 2,184,000 $ 728,750 $ 398,985 January 19, 2018 Braddock Metro Center Office N/A 356,000 $ 93,000 $ — June 28, 2018 2445 M Street Office N/A 292,000 101,600 2,495 Total 2018 648,000 $ 194,600 $ 2,495 ______________________________ (1) Consists of 925 and 1000 Corporate Drive. (2) Consists of five retail properties: Gateway Overlook, Wheaton Park, Olney Village Center, Bradlee Shopping Center and Shoppes of Foxchase. The results of the Retail Portfolio are classified as discontinued operations and are summarized as follows (amounts in thousands, except for share data): Year Ended December 31, 2019 2018 Real estate rental revenue $ 28,200 $ 45,160 Real estate expenses (6,803) (10,638) Depreciation and amortization (4,926) (9,402) Interest expense (313) (643) Loss on extinguishment of debt (764) — Gain on sale of real estate 339,024 — Income from discontinued operations $ 354,418 $ 24,477 Basic net income per share $ 4.39 $ 0.31 Diluted net income per share $ 4.39 $ 0.31 Capital expenditures $ 809 $ 2,138 All assets and liabilities related to the Retail Portfolio were sold as of December 31, 2019.

Lease Accounting (Tables)

Lease Accounting (Tables)	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Schedule of Future Minimum Rental Income	As of December 31, 2020, non-cancelable commercial operating leases provide for future minimum rental income from continuing operations as follows (in thousands): 2021 $ 122,062 2022 109,939 2023 93,467 2024 80,793 2025 63,923 Thereafter 215,443 $ 685,627
Schedule of Obligations for Future Minimum Payments on Operating Ground Lease	The following table sets forth the undiscounted cash flows of our scheduled obligations for future minimum payments on our operating ground lease as of December 31, 2020 and a reconciliation of those cash flows to the operating lease liability as of December 31, 2020 (in thousands): 2021 $ 260 2022 260 2023 260 2024 260 2025 260 Thereafter 11,635 12,935 Imputed interest (9,203) Lease liability $ 3,732

Mortgage Notes Payable (Tables)

Mortgage Notes Payable (Tables)	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Schedule of Outstanding Mortgage Notes Payable	As of December 31, 2019, we had one outstanding mortgage notes payable, collateralized by a building and related land from our portfolio, as follows (in thousands): Properties Assumption/Issuance Date (1) Effective Interest Rate (2) December 31, 2019 Yale West 2/21/2014 3.75 % $ 45,654 Premiums and discounts, net 1,470 Debt issuance costs, net (50) $ 47,074 ______________________________ (1) This mortgage was assumed with the acquisition of the collateralized property. 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.

Unsecured Lines of Credit Pay_2

Unsecured Lines of Credit Payable (Tables)	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Schedule of Revolving Credit Facilities	The amount of the Revolving Credit Facility unused and available at December 31, 2020 was as follows (in thousands): Committed capacity $ 700,000 Borrowings outstanding (42,000) Unused and available $ 658,000 We executed borrowings and repayments on the Revolving Credit Facility during 2020 as follows (in thousands): Balance at December 31, 2019 $ 56,000 Borrowings 732,000 Repayments (746,000) Balance at December 31, 2020 $ 42,000 For the three years ended December 31, 2020, we recognized interest expense (excluding facility fees) and facility fees as follows (in thousands): Year Ended December 31, 2020 2019 2018 Interest expense (excluding facility fees) $ 3,035 $ 6,554 $ 6,843 Facility fees 1,423 1,400 1,371 Information related to revolving credit facilities for the three years ended December 31, 2020 as follows (in thousands, except percentage amounts): Year Ended December 31, 2020 2019 2018 Total revolving credit facilities at December 31 $ 700,000 $ 700,000 $ 700,000 Borrowings outstanding at December 31 42,000 56,000 188,000 Weighted average daily borrowings during the year 204,809 196,074 230,934 Maximum daily borrowings during the year 456,000 300,000 429,000 Weighted average interest rate during the year 1.48 % 3.34 % 2.96 % Weighted average interest rate on borrowings outstanding at December 31 1.15 % 2.73 % 3.52 %

Notes Payable (Tables)

Notes Payable (Tables)	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Schedule of Unsecured Notes and Term Loans Outstanding	Our unsecured notes and term loans outstanding as of December 31, 2020 and 2019 are as follows (in thousands): Effective December 31, Payoff Date/ Coupon/Stated Rate Rate (1) 2020 2019 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 % 300,000 300,000 10/15/2022 2018 Term Loan (3) 1 Month LIBOR + 110 basis points 2.87 % 250,000 250,000 7/21/2023 30-Year Unsecured Notes 7.25 % 7.36 % 50,000 50,000 2/25/2028 Green Bonds 3.44 % 4.09 % 350,000 — 12/29/2030 Total principal 950,000 1,000,000 Premiums and discounts, net (456) (797) Deferred issuance costs, net (4,174) (2,481) Total $ 945,370 $ 996,722 ______________________________ (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 8). (2) No principal amounts are due prior to maturity. (3) The 2018 Term Loan increased and replaced the 2016 Term Loan (see note 6).
Schedule of Required Principal Payments on Unsecured Notes and Term Loans	The required principal payments on the unsecured notes and term loans as of December 31, 2020 are as follows (in thousands): 2021 $ — 2022 300,000 2023 250,000 2024 — 2025 — Thereafter 400,000 $ 950,000

Derivative Instruments (Tables)

Derivative Instruments (Tables)	12 Months Ended
	Dec. 31, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments	The fair values of the interest rate swaps as of December 31, 2020 and 2019, are as follows (in thousands): Aggregate Effective Date Fair Value Derivative Assets (Liabilities) December 31, Derivative Instrument Maturity Date 2020 2019 Interest rate swaps $ 150,000 October 15, 2015 March 15, 2021 $ — $ (62) Interest rate swaps 150,000 March 31, 2017 July 21, 2023 (4,009) 1,825 Interest rate swaps 100,000 June 29, 2018 July 21, 2023 (6,246) (3,664) Interest rate swaps 200,000 April 1, 2020 April 1, 2030 — 3,724 $ (10,255) $ 1,823
Schedule of Unrealized Gain (Loss) and Reclassification of Interest Rate Swap	The gains or losses on the effective swaps are recognized in other comprehensive income, as follows (in thousands): Year Ending December 31, 2020 2019 2018 Unrealized (loss) gain on interest rate hedges $ (33,025) $ (8,016) $ 420 Amounts reported in Accumulated other comprehensive income related to derivatives will be reclassified to interest expense as interest payments are made on our variable-rate debt. The gains or losses reclassified from Accumulated other comprehensive income into interest expense for the three years ended December 31, 2020, were as follows (in thousands): Year Ending December 31, 2020 2019 2018 Loss reclassified from Accumulated other comprehensive income (loss) into interest expense $ 79 $ — $ —

Fair Value Disclosures (Tables)

Fair Value Disclosures (Tables)	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Schedule of Fair Value of Financial Assets and Liabilities	The fair values of these assets and liabilities at December 31, 2020 and 2019 were as follows (in thousands): December 31, 2020 December 31, 2019 Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs Significant Unobservable Inputs Fair Value Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Assets: SERP $ 2,433 $ — $ 2,433 $ — $ 1,792 $ — $ 1,792 $ — Interest rate swaps — — — — 5,549 — 5,549 — Liabilities: Interest rate swaps $ (10,255) $ — $ (10,255) $ — $ (3,726) $ — $ (3,726) $ —
Schedule of Carrying Value and Estimated Fair Value of Financial Instruments	As of December 31, 2020 and 2019, the carrying values and estimated fair values of our financial instruments were as follows (in thousands): December 31, 2020 2019 Carrying Fair Value Carrying Fair Value Cash and cash equivalents $ 7,700 $ 7,700 $ 12,939 $ 12,939 Restricted cash 603 603 1,812 1,812 Mortgage notes payable — — 47,074 47,899 Line of credit payable 42,000 42,000 56,000 56,000 Notes payable 945,370 978,678 996,722 1,022,937

Stock Based Compensation (Table

Stock Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2020
Share-based Payment Arrangement, Noncash Expense [Abstract]
Schedule of Award Valuation Performance Period Metrics	Each participant’s total award under the Officer STIP with respect to a performance period will be stated as a percentage of the participant’s annual base salary determined as of the first day of that performance period, which percentage will depend upon the participant’s position and the degree of achievement of threshold, target, and high performance goals for the performance period which, except as otherwise determined by the Compensation Committee, will be as set forth in the table below: Threshold Target High President and Chief Executive Officer 63% 125% 188% Executive Vice President 48% 93% 160% Senior Vice President 35% 65% 115% Threshold Target High President and Chief Executive Officer 198% 275% 440% Executive Vice President 143% 200% 295% Senior Vice President 100% 143% 207%
Schedule of Assumptions Used to Value TSR Portion of LTIP Awards	The assumptions used to value the TSR portion of the officer LTIP and Prior LTIP awards were as follows: 2020 Awards 2019 Awards 2018 Awards Expected volatility (1) 17.5 % 18.1 % 17.9 % Risk-free interest rate (2) 1.4 % 2.4 % 2.4 % Expected term (3) 3 years 3 and 4 years 3 and 4 years Share price at grant date $31.50 $23.00 $ 26.06 ______________________________ (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 Activity	The activity for the three years ended December 31, 2020 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, 2017 236,694 $ 27.96 Granted 304,087 25.98 Vested during year (224,150) 27.40 Forfeited (5,621) 29.43 Unvested at December 31, 2018 311,010 29.07 Granted 213,782 26.26 Vested during year (236,013) 27.43 Forfeited (19,396) 26.60 Unvested at December 31, 2019 269,383 28.45 Granted 285,101 30.39 Vested during year (239,033) 27.54 Forfeited (8,456) 28.35 Unvested at December 31, 2020 306,995 30.96
Schedule of Performance Share Units with Market Conditions	Stock based awards with market conditions under the LTIP and Prior LTIP were granted in 2020, 2019 and 2018 with fair market values, as determined using a Monte Carlo simulation, as follows (in thousands): 2020 Awards 2019 Awards 2018 Awards Unrestricted (1) Restricted Unrestricted Restricted Unrestricted Relative Peer TSR $ 510 $ 184 $ 552 $ 203 $ 608 Absolute/Index TSR (2) 565 201 602 230 690
Schedule Of Unamortized Value Of Awards With Market Conditions	The unamortized value of these awards with market conditions as of December 31, 2020 was as follows (in thousands): 2020 Awards 2019 Awards 2018 Awards Unrestricted Restricted Unrestricted Restricted Unrestricted Relative Peer TSR $ 355 $ 92 $ 184 $ 42 $ — Absolute/Index TSR (1) 393 100 201 48 — ______________________________ (1) The 2020 Awards were granted under the 2020 LTIP, whereby all of the shares vest immediately at the end of the three-year performance period. The 2019 and 2018 Awards were granted under the Prior LTIP, whereby the unrestricted shares (75%) vest immediately at the end of the three-year performance period and the restricted shares (25%) vest over a one-year period commencing on the January 1 following the end of the three-year performance period.

Earnings Per Common Share (Tabl

Earnings Per Common Share (Tables)	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Schedule of Computation of Basic and Diluted Earnings Per Share	The computation of basic and diluted earnings per share for the three years ended December 31, 2020 was as follows (in thousands, except per share data): Year Ended December 31, 2020 2019 2018 Numerator: (Loss) income from continuing operations $ (15,680) $ 29,132 $ 1,153 Allocation of distributed earnings to unvested restricted share awards to continuing operations (545) (125) (526) Adjusted (loss) income from continuing operations (16,225) 29,007 627 Income from discontinued operations, including gain on sale of real estate — 354,418 24,477 Allocation of earnings from discontinued operations to unvested restricted share awards — (1,837) — Adjusted income from discontinued operations — 352,581 24,477 Adjusted net (loss) income $ (16,225) $ 381,588 $ 25,104 Denominator: Weighted average shares outstanding – basic 82,348 80,257 78,960 Effect of dilutive securities: Operating partnership units — 12 12 Employee restricted share awards — 66 70 Weighted average shares outstanding – diluted 82,348 80,335 79,042 Earnings per common share, basic: Continuing operations $ (0.20) $ 0.36 $ 0.01 Discontinued operations — 4.39 0.31 Basic net (loss) income per common share $ (0.20) $ 4.75 $ 0.32 Earnings per common share, diluted: Continuing operations $ (0.20) $ 0.36 $ 0.01 Discontinued operations — 4.39 0.31 Diluted net (loss) income per common share $ (0.20) $ 4.75 $ 0.32 Dividends declared per common share $ 1.20 $ 1.20 $ 1.20

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2020
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Schedule of Real Estate Rental Revenue as a Percentage	Real estate rental revenue as a percentage of the total for each of the reportable operating segments for the three years ended December 31, 2020 was as follows: Year Ended December 31, 2020 2019 2018 Multifamily 49 % 41 % 33 % Office 45 % 53 % 61 % Corporate and other 6 % 6 % 6 %
Schedule of Percentage of Income Producing Real Estate Assets by Segment	The percentage of income producing real estate assets classified as held and used, at cost, for each of the reportable operating segments as of December 31, 2020 and 2019 was as follows: December 31, 2020 2019 Multifamily 54 % 50 % Office 41 % 45 % Corporate and other 5 % 5 %
Schedule of 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, 2020 from these segments, and reconciles net operating income of reportable segments to net (loss) income as reported (in thousands): Year Ended December 31, 2020 Office Multifamily Corporate (1) Consolidated Real estate rental revenue $ 132,327 $ 145,045 $ 16,746 $ 294,118 Real estate expenses 49,452 58,115 5,342 112,909 Net operating income $ 82,875 $ 86,930 $ 11,404 $ 181,209 Depreciation and amortization (120,030) General and administrative (23,951) Interest expense (37,305) Loss on interest rate derivatives (560) Loss on extinguishment of debt (34) Loss on sale of real estate (15,009) Net loss $ (15,680) Capital expenditures $ 31,148 $ 24,675 $ 2,494 $ 58,317 Total assets $ 940,069 $ 1,333,235 $ 136,514 $ 2,409,818 Year Ended December 31, 2019 Office Multifamily Corporate and Other (1) Consolidated Real estate rental revenue $ 164,059 $ 126,131 $ 18,990 $ 309,180 Real estate expenses 60,923 49,135 5,522 115,580 Net operating income $ 103,136 $ 76,996 $ 13,468 $ 193,600 Depreciation and amortization (136,253) General and administrative (26,068) Real estate impairment (8,374) Interest expense (53,734) Gain on sale of real estate 59,961 Discontinued operations: Income from properties sold or held for sale 16,158 Gain on sale of real estate 339,024 Loss on extinguishment of debt (764) Net income $ 383,550 Capital expenditures $ 38,634 $ 25,779 $ 4,534 $ 68,947 Total assets $ 1,134,147 $ 1,340,634 $ 153,547 $ 2,628,328 Year Ended December 31, 2018 Office Multifamily Corporate and Other (1) Consolidated Real estate rental revenue $ 178,474 95,194 18,062 $ 291,730 Real estate expenses 63,321 37,235 5,036 105,592 Net operating income $ 115,153 $ 57,959 $ 13,026 $ 186,138 Depreciation and amortization (111,826) General and administrative (22,089) Interest expense (50,501) Real estate impairment (1,886) Loss on extinguishment of debt (1,178) Gain on sale of real estate 2,495 Discontinued operations: Income from properties sold or held for sale 24,477 Net income $ 25,630 Capital expenditures $ 42,019 $ 25,117 $ 4,897 $ 72,033 Total assets $ 1,248,673 $ 792,170 $ 376,261 $ 2,417,104 ______________________________ (1) Includes the retail properties not classified as discontinued operations: Takoma Park, Westminster, Concord Centre, Chevy Chase Metro Plaza, 800 S. Washington Street, Randolph Shopping Center, Montrose Shopping Center and Spring Valley Village, and total assets and capital expenditures include all retail properties, including those classified as discontinued operations.

Selected Quarterly Financial _2

Selected Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information	Unaudited financial data by quarter in each of the years ended December 31, 2020 and 2019 were as follows (in thousands, except for per share data): Quarter (1), (2) First Second Third Fourth 2020 Real estate rental revenue $ 76,792 $ 72,870 $ 73,227 $ 71,229 Income (loss) from continuing operations $ 1,719 $ (5,406) $ (956) $ (11,037) Net income (loss) $ 1,719 $ (5,406) $ (956) $ (11,037) Income (loss) from continuing operations per share Basic $ 0.02 $ (0.07) $ (0.01) $ (0.13) Diluted $ 0.02 $ (0.07) $ (0.01) $ (0.13) Net income (loss) per share Basic $ 0.02 $ (0.07) $ (0.01) $ (0.13) Diluted $ 0.02 $ (0.07) $ (0.01) $ (0.13) 2019 Real estate rental revenue $ 71,434 $ 76,820 $ 80,259 $ 80,667 (Loss) income from continuing operations $ (10,443) $ (6,191) $ (8,432) $ 54,198 Net (loss) income $ (4,405) $ 987 $ 332,770 $ 54,198 (Loss) income from continuing operations per share Basic $ (0.13) $ (0.08) $ (0.10) $ 0.66 Diluted $ (0.13) $ (0.08) $ (0.10) $ 0.66 Net (loss) income per share Basic $ (0.06) $ 0.01 $ 4.14 $ 0.66 Diluted $ (0.06) $ 0.01 $ 4.14 $ 0.66 ______________________________ (1) With regard to per share calculations, the sum of the quarterly results may not equal full year results due to rounding.

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
Schedule of Issuances and Net Proceeds from 2018 Equity Distribution Agreements	Our issuances and net proceeds on the 2018 Equity Distribution Agreements for the three years ended December 31, 2020 were as follows (in thousands, except per share data): Year Ended December 31, 2020 2019 2018 Issuance of common shares 2,000 1,859 1,165 Weighted average price per share $ 23.86 $ 30.00 $ 31.18 Net proceeds $ 48,355 $ 54,916 $ 35,472
Schedule of Issuances and Net Proceeds from Dividend Reinvestment Program	Our issuances and net proceeds on the dividend reinvestment program for the three years ended December 31, 2020 were as follows (in thousands, except per share data): Year Ended December 31, 2020 2019 2018 Issuance of common shares 89 173 81 Weighted average price per share $ 24.12 $ 27.58 $ 29.18 Net proceeds $ 2,121 $ 4,755 $ 1,973

Deferred Costs (Tables)

Deferred Costs (Tables)	12 Months Ended
	Dec. 31, 2020
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Schedule of Deferred Leasing Costs and Deferred Leasing Incentives	As of December 31, 2020 and 2019, deferred leasing costs and deferred leasing incentives were included in prepaid expenses and other assets as follows (in thousands): December 31, 2020 2019 Gross Carrying Accumulated Net Gross Carrying Accumulated Net Deferred leasing costs $ 55,736 $ 30,700 $ 25,036 $ 60,900 $ 29,580 $ 31,320 Deferred leasing incentives 22,942 18,076 4,866 18,926 11,133 7,793
Schedule of Amortization and Write-offs of Deferred Leasing Costs and Deferred Leasing Incentives	Amortization, including write-offs, of deferred leasing costs and deferred leasing incentives for the three years ended December 31, 2020 were as follows (in thousands): Year Ended December 31, 2020 2019 2018 Deferred leasing costs amortization $ 5,389 $ 6,599 $ 5,881 Deferred leasing incentives amortization 2,070 2,862 2,811

Nature of Business - Properties

Nature of Business - Properties Sold (Details) $ in Thousands

Dec. 17, 2020USD ($)

Dec. 02, 2020USD ($)

Apr. 21, 2020USD ($)

Dec. 19, 2019USD ($)

Aug. 27, 2019USD ($)

Aug. 21, 2019USD ($)

Jul. 23, 2019USD ($)property

Jun. 26, 2019USD ($)

Jun. 28, 2018USD ($)

Jan. 19, 2018USD ($)

Dec. 31, 2020USD ($)

Jun. 30, 2020USD ($)

Dec. 31, 2019USD ($)

Sep. 30, 2019USD ($)

Jun. 30, 2019USD ($)

Dec. 31, 2020USD ($)

Dec. 31, 2019USD ($)property

Dec. 31, 2018USD ($)

Properties Sold [Line Items]

(Loss) gain on sale

$ 339,000

$ 0

$ 339,024

$ 0

(Loss) gain on sale

$ (7,500)

$ (7,500)

$ 61,000

$ (1,000)

(15,009)

$ 59,961

2,495

Number of retail properties sold | property

8

2020 Properties

Properties Sold [Line Items]

(Loss) gain on sale

$ (14,325)

2020 Properties | Disposal group, not discontinued operations | John Marshall II | Office

Properties Sold [Line Items]

(Loss) gain on sale

$ (6,855)

2020 Properties | Disposal group, not discontinued operations | Monument II | Office

Properties Sold [Line Items]

(Loss) gain on sale

$ (8,595)

2020 Properties | Disposal group, not discontinued operations | 1227 25th Street | Office

Properties Sold [Line Items]

(Loss) gain on sale

$ 1,125

2019 Properties

Properties Sold [Line Items]

(Loss) gain on sale

$ 398,985

2019 Properties | Disposal group, not discontinued operations | Quantico Corporate Center | Office

Properties Sold [Line Items]

(Loss) gain on sale

$ (1,046)

2019 Properties | Disposal group, not discontinued operations | 1776 G Street | Office

Properties Sold [Line Items]

(Loss) gain on sale

$ 61,007

2019 Properties | Discontinued operations | Shopping Center Portfolio | Retail

Properties Sold [Line Items]

(Loss) gain on sale

$ 333,023

Number of retail properties sold | property

5

2019 Properties | Discontinued operations | Frederick Crossing and Frederick County Square | Retail

Properties Sold [Line Items]

(Loss) gain on sale

$ 9,507

2019 Properties | Discontinued operations | Centre at Hagerstown | Retail

Properties Sold [Line Items]

(Loss) gain on sale

$ (3,506)

2018 Properties

Properties Sold [Line Items]

(Loss) gain on sale

$ 2,495

2018 Properties | Disposal group, not discontinued operations | Braddock Metro Center | Office

Properties Sold [Line Items]

(Loss) gain on sale

$ 0

2018 Properties | Disposal group, not discontinued operations | 2445 M Street | Office

Properties Sold [Line Items]

(Loss) gain on sale

$ 2,495

Nature of Business - Narrative

Nature of Business - Narrative (Details)	12 Months Ended
	Dec. 31, 2019USD ($)property	Dec. 31, 2020USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of retail properties sold that were identified for deferred exchange under Section 1031 | property	7
Number of retail properties sold | property	8
Number of multifamily properties acquired | property	8
TRS
Taxes, Miscellaneous [Abstract]
Deferred tax asset | $	$ 1,400,000	$ 1,400,000
Deferred tax asset valuation allowance | $	1,400,000	1,400,000
Deferred tax liabilities | $	$ 600,000	$ 0

Nature of Business - Taxable Pe

Nature of Business - Taxable Percentage of Dividends (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Ordinary income/Section 199A dividends	36.00%	80.00%	29.00%
Return of capital	64.00%	20.00%	71.00%
Qualified dividends	0.00%	0.00%	0.00%
Unrecaptured Section 1250 gain	0.00%	0.00%	0.00%
Capital gain	0.00%	0.00%	0.00%

Summary of Significant Accoun_4

Summary of Significant Accounting Policies and Basis of Presentation - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Equity	$ (1,321,109)	$ (1,412,062)	$ (1,068,478)	$ (1,095,336)
Real estate depreciation	$ 103,400	101,700	82,900
Buildings | Minimum
Property, Plant and Equipment [Line Items]
Useful life (in years)	28 years
Buildings | Maximum
Property, Plant and Equipment [Line Items]
Useful life (in years)	50 years
Capital improvements | Minimum
Property, Plant and Equipment [Line Items]
Useful life (in years)	3 years
Capital improvements | Maximum
Property, Plant and Equipment [Line Items]
Useful life (in years)	40 years
Distributions in Excess of Net Income
Property, Plant and Equipment [Line Items]
Equity	$ 298,860	$ 183,405	469,085	$ 399,213
Cumulative effect of change in accounting principle
Property, Plant and Equipment [Line Items]
Equity			906
Cumulative effect of change in accounting principle | Distributions in Excess of Net Income
Property, Plant and Equipment [Line Items]
Equity			906
ASU 2016-02 | Cumulative effect of change in accounting principle | Distributions in Excess of Net Income
Property, Plant and Equipment [Line Items]
Equity			$ 900
Multifamily Properties
Property, Plant and Equipment [Line Items]
Lessor operating lease term (in years)	1 year
Commercial Properties
Property, Plant and Equipment [Line Items]
Lessor operating lease term (in years)	7 years

Summary of Significant Accoun_5

Summary of Significant Accounting Policies and Basis of Presentation - Interest Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Total interest incurred	$ 39,524	$ 56,948	$ 52,592
Capitalized interest	(2,219)	(3,214)	(2,091)
Interest expense, net of capitalized interest	$ 37,305	$ 53,734	$ 50,501

Real Estate - Real Estate Inves

Real Estate - Real Estate Investment Portfolio (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Real Estate [Line Items]
Income producing property, at cost	$ 2,983,617	$ 2,959,222
Properties under development or held for future development	37,615	124,193
Multifamily
Real Estate [Line Items]
Income producing property, at cost	1,606,085	1,469,011
Properties under development or held for future development	36,493	123,071
Office
Real Estate [Line Items]
Income producing property, at cost	1,214,481	1,329,722
Properties under development or held for future development	478	478
Other
Real Estate [Line Items]
Income producing property, at cost	163,051	160,489
Properties under development or held for future development	$ 644	$ 644

Real Estate - Acquisitions (Det

Real Estate - Acquisitions (Details) ft² in Thousands	Jul. 23, 2019USD ($)unit	Jun. 27, 2019USD ($)unit	Apr. 30, 2019USD ($)unit	Jan. 18, 2018USD ($)ft²	Dec. 31, 2020USD ($)ft²	Dec. 31, 2019USD ($)unit
Real Estate [Line Items]
Rentable Square Feet (sq ft) | ft²					9,461
Contract Purchase Price					$ 0
2019 Acquisitions
Real Estate [Line Items]
Number of units | unit						2,390
Contract Purchase Price						$ 530,920,000
Multifamily
Real Estate [Line Items]
Rentable Square Feet (sq ft) | ft²					6,097
Multifamily | 2019 Acquisitions | Assembly Portfolio - Virginia
Real Estate [Line Items]
Number of units | unit			1,685
Contract Purchase Price			$ 379,100,000
Multifamily | 2019 Acquisitions | Assembly Portfolio - Maryland
Real Estate [Line Items]
Number of units | unit		428
Contract Purchase Price		$ 82,070,000
Multifamily | 2019 Acquisitions | Cascade at Landmark
Real Estate [Line Items]
Number of units | unit	277
Contract Purchase Price	$ 69,750,000
Office
Real Estate [Line Items]
Rentable Square Feet (sq ft) | ft²					2,665
Office | 2018 Acquisitions | Arlington Tower
Real Estate [Line Items]
Rentable Square Feet (sq ft) | ft²				391
Contract Purchase Price				$ 250,000,000

Real Estate - Revenue and Incom

Real Estate - Revenue and Income (Loss) for Acquired Properties (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
2019 Acquisitions
Real Estate [Line Items]
Real estate rental revenue	$ 27,641
Net (loss) income	$ (10,167)
2018 Acquisitions
Real Estate [Line Items]
Real estate rental revenue		$ 22,389
Net (loss) income		$ 3,623

Real Estate - Cost Allocation o

Real Estate - Cost Allocation of Asset Acquisitions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
2019 Acquisitions
Real Estate [Line Items]
Net lease intangible liabilities	$ 0
Total	531,528
2019 Acquisitions | Tenant origination costs
Real Estate [Line Items]
Intangible assets	0
2019 Acquisitions | Leasing commissions absorption costs
Real Estate [Line Items]
Intangible assets	15,474
2019 Acquisitions | Net lease intangible assets
Real Estate [Line Items]
Intangible assets	0
2019 Acquisitions | Land
Real Estate [Line Items]
Property, plant and equipment	92,391
2019 Acquisitions | Building and improvements
Real Estate [Line Items]
Property, plant and equipment	$ 423,663
2018 Acquisitions
Real Estate [Line Items]
Net lease intangible liabilities		$ (545)
Total		250,557
2018 Acquisitions | Tenant origination costs
Real Estate [Line Items]
Intangible assets		13,625
2018 Acquisitions | Leasing commissions absorption costs
Real Estate [Line Items]
Intangible assets		27,465
2018 Acquisitions | Net lease intangible assets
Real Estate [Line Items]
Intangible assets		3,142
2018 Acquisitions | Land
Real Estate [Line Items]
Property, plant and equipment		63,970
2018 Acquisitions | Building and improvements
Real Estate [Line Items]
Property, plant and equipment		$ 142,900

Real Estate - Portfolio and Acq

Real Estate - Portfolio and Acquisitions Narrative (Details)	12 Months Ended
	Dec. 31, 2020USD ($)unit	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Real Estate [Line Items]
Investment in development of property	$ 37,615,000	$ 124,193,000
Contract purchase price	0
Total cost of acquisition		531,500,000	$ 250,000,000
Real estate acquisitions, net	0	528,589,000	106,400,000
Credits received at settlement		2,900,000
Mortgage note assumed and repaid at settlement	46,567,000	$ 12,724,000	170,081,000
Acquisition deposit			6,300,000
Credit settlement adjustment			2,400,000
Capitalized asset acquisition-related costs			600,000
The Trove
Real Estate [Line Items]
Total investment to date in real estate property for development	$ 133,500,000
Number of units completed and delivered | unit	374
Assets placed into service	$ 126,400,000
Riverside Developments
Real Estate [Line Items]
Investment in development of property	$ 28,600,000
Arlington Tower
Real Estate [Line Items]
Mortgage note assumed and repaid at settlement			$ 135,500,000

Real Estate - Net Balances of C

Real Estate - Net Balances of Components of Fair Value of In-Place Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Tenant origination costs
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 43,536	$ 50,155
Accumulated Amortization	30,096	33,364
Net	13,440	16,791
Leasing commissions absorption costs
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	107,102	122,348
Accumulated Amortization	83,588	92,401
Net	23,514	29,947
Net lease intangible assets
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	11,595	15,183
Accumulated Amortization	9,390	11,964
Net	2,205	3,219
Net lease intangible liabilities
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	27,809	29,836
Accumulated Amortization	20,247	20,854
Net	7,562	8,982
Below-market ground lease intangible asset
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	12,080	12,080
Accumulated Amortization	2,472	2,282
Net	$ 9,608	$ 9,798

Real Estate - Amortization of C

Real Estate - Amortization of Combined Components (Details) - Acquired-in-place leases - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Depreciation and amortization expense	$ 9,997	$ 27,123	$ 22,361
Real estate rental revenue increase, net	(406)	(924)	(1,225)
Depreciation and amortization expense, net of revenue effect	$ 9,591	$ 26,199	$ 21,136

Real Estate - Amortization of_2

Real Estate - Amortization of Combined Components Over Next Five Years (Details) - Acquired-in-place leases $ in Thousands	Dec. 31, 2020USD ($)
Depreciation and amortization expense
2021	$ 8,576
2022	8,078
2023	6,032
2024	5,264
2025	4,231
Thereafter	14,380
Real estate rental revenue, net increase
2021	(547)
2022	(736)
2023	(974)
2024	(862)
2025	(777)
Thereafter	(1,460)
Total
2021	8,029
2022	7,342
2023	5,058
2024	4,402
2025	3,454
Thereafter	$ 12,920

Real Estate - Properties Sold a

Real Estate - Properties Sold and Held for Sale (Details) ft² in Thousands, $ in Thousands	Dec. 17, 2020USD ($)ft²	Dec. 02, 2020USD ($)ft²	Apr. 21, 2020USD ($)ft²	Dec. 19, 2019USD ($)ft²	Aug. 27, 2019USD ($)ft²	Aug. 21, 2019USD ($)ft²	Jul. 23, 2019USD ($)ft²property	Jun. 26, 2019USD ($)ft²	Jun. 28, 2018USD ($)ft²	Jan. 19, 2018USD ($)ft²	Dec. 31, 2020USD ($)ft²	Jun. 30, 2020USD ($)	Dec. 31, 2019USD ($)ft²	Sep. 30, 2019USD ($)	Jun. 30, 2019USD ($)	Dec. 31, 2020USD ($)ft²	Dec. 31, 2019USD ($)ft²property	Dec. 31, 2018USD ($)ft²	Mar. 31, 2018USD ($)ft²
Properties Sold [Line Items]
(Loss) gain on sale											$ (7,500)	$ (7,500)	$ 61,000		$ (1,000)	$ (15,009)	$ 59,961	$ 2,495
(Loss) gain on sale														$ 339,000		$ 0	$ 339,024	$ 0
Number of retail properties sold | property																	8
2020 Properties
Properties Sold [Line Items]
Rentable square feet (sq ft) | ft²											565					565
Contract sales price											$ 163,500					$ 163,500
(Loss) gain on sale																$ (14,325)
2020 Properties | Disposal group, not discontinued operations | John Marshall II | Office
Properties Sold [Line Items]
Rentable square feet (sq ft) | ft²			223
Contract sales price			$ 57,000										$ 63,400				$ 63,400
(Loss) gain on sale			$ (6,855)
2020 Properties | Disposal group, not discontinued operations | Monument II | Office
Properties Sold [Line Items]
Rentable square feet (sq ft) | ft²		207
Contract sales price		$ 53,000
(Loss) gain on sale		$ (8,595)
2020 Properties | Disposal group, not discontinued operations | 1227 25th Street | Office
Properties Sold [Line Items]
Rentable square feet (sq ft) | ft²	135
Contract sales price	$ 53,500
(Loss) gain on sale	$ 1,125
2019 Properties
Properties Sold [Line Items]
Rentable square feet (sq ft) | ft²													2,184				2,184
Contract sales price													$ 728,750				$ 728,750
(Loss) gain on sale																	$ 398,985
2019 Properties | Disposal group, not discontinued operations | Quantico Corporate Center | Office
Properties Sold [Line Items]
Rentable square feet (sq ft) | ft²								272
Contract sales price								$ 33,000
(Loss) gain on sale								$ (1,046)
2019 Properties | Disposal group, not discontinued operations | 1776 G Street | Office
Properties Sold [Line Items]
Rentable square feet (sq ft) | ft²				262
Contract sales price				$ 129,500
(Loss) gain on sale				$ 61,007
2019 Properties | Discontinued operations | Shopping Center Portfolio | Retail
Properties Sold [Line Items]
Rentable square feet (sq ft) | ft²							800
Contract sales price							$ 485,250
(Loss) gain on sale							$ 333,023
Number of retail properties sold | property							5
2019 Properties | Discontinued operations | Frederick Crossing and Frederick County Square | Retail
Properties Sold [Line Items]
Rentable square feet (sq ft) | ft²						520
Contract sales price						$ 57,500
(Loss) gain on sale						$ 9,507
2019 Properties | Discontinued operations | Centre at Hagerstown | Retail
Properties Sold [Line Items]
Rentable square feet (sq ft) | ft²					330
Contract sales price					$ 23,500
(Loss) gain on sale					$ (3,506)
2018 Properties
Properties Sold [Line Items]
Rentable square feet (sq ft) | ft²																		648
Contract sales price																		$ 194,600
(Loss) gain on sale																		$ 2,495
2018 Properties | Disposal group, not discontinued operations | Braddock Metro Center | Office
Properties Sold [Line Items]
Rentable square feet (sq ft) | ft²										356
Contract sales price										$ 93,000
(Loss) gain on sale										$ 0
2018 Properties | Disposal group, not discontinued operations | 2445 M Street | Office
Properties Sold [Line Items]
Rentable square feet (sq ft) | ft²									292										292
Contract sales price									$ 101,600										$ 100,000
(Loss) gain on sale									$ 2,495

Real Estate - Properties Sold_2

Real Estate - Properties Sold and Held for Sale Narrative (Details) ft² in Thousands, $ in Thousands	Dec. 17, 2020USD ($)ft²	Dec. 02, 2020USD ($)ft²	Apr. 21, 2020USD ($)ft²	Dec. 19, 2019USD ($)ft²	Aug. 27, 2019USD ($)ft²	Aug. 21, 2019USD ($)ft²	Jul. 23, 2019USD ($)ft²	Jun. 26, 2019USD ($)ft²building	Jun. 28, 2018USD ($)ft²	Jan. 19, 2018USD ($)ft²	Jun. 30, 2019agreementbuyer	Dec. 31, 2020USD ($)ft²	Jun. 30, 2020USD ($)	Dec. 31, 2019USD ($)ft²	Sep. 30, 2019USD ($)	Jun. 30, 2019USD ($)	Mar. 31, 2019USD ($)	Mar. 31, 2018USD ($)ft²	Dec. 31, 2020USD ($)ft²	Dec. 31, 2019USD ($)ft²	Dec. 31, 2018USD ($)ft²	Dec. 31, 2017USD ($)
Real Estate [Line Items]
(Loss) gain on sale												$ (7,500)	$ (7,500)	$ 61,000		$ (1,000)			$ (15,009)	$ 59,961	$ 2,495
(Loss) gain on sale															$ 339,000				0	339,024	0
Impairment of real estate																			0	8,374	1,886
Loss on extinguishment of debt																			0	764	0
2020 Properties
Real Estate [Line Items]
Contract sales price												$ 163,500							163,500
(Loss) gain on sale																			$ (14,325)
Area of property (sq ft) | ft²												565							565
2019 Properties
Real Estate [Line Items]
Contract sales price														$ 728,750						$ 728,750
Area of property (sq ft) | ft²														2,184						2,184
2019 Properties | Discontinued operations
Real Estate [Line Items]
Loss on extinguishment of debt															$ 800
2018 Properties
Real Estate [Line Items]
Contract sales price																					194,600
(Loss) gain on sale																					$ 2,495
Area of property (sq ft) | ft²																					648
1227 25th Street | Office | 2020 Properties | Disposal group, not discontinued operations
Real Estate [Line Items]
Contract sales price	$ 53,500
(Loss) gain on sale	$ 1,125
Area of property (sq ft) | ft²	135
Monument II | Office | 2020 Properties | Disposal group, not discontinued operations
Real Estate [Line Items]
Contract sales price		$ 53,000
(Loss) gain on sale		$ (8,595)
Area of property (sq ft) | ft²		207
John Marshall II | Office | 2020 Properties | Disposal group, not discontinued operations
Real Estate [Line Items]
Contract sales price			$ 57,000											$ 63,400						$ 63,400
(Loss) gain on sale			$ (6,855)
Area of property (sq ft) | ft²			223
Quantico Corporate Center | Office | 2019 Properties | Disposal group, not discontinued operations
Real Estate [Line Items]
Contract sales price								$ 33,000
(Loss) gain on sale								$ (1,046)
Number of buildings | building								2
Area of property (sq ft) | ft²								272
Impairment of real estate																	$ 8,400
Shopping Center Portfolio and Power Center Portfolio
Real Estate [Line Items]
Number of purchase and sale agreements | agreement											2
Number of buyers | buyer											2
Shopping Center Portfolio | Retail Centers | 2019 Properties | Discontinued operations
Real Estate [Line Items]
Contract sales price							$ 485,250
(Loss) gain on sale							$ 333,023
Area of property (sq ft) | ft²							800
Frederick Crossing and Frederick County Square | Retail Centers | 2019 Properties | Discontinued operations
Real Estate [Line Items]
Contract sales price						$ 57,500
(Loss) gain on sale						$ 9,507
Area of property (sq ft) | ft²						520
Centre at Hagerstown | Retail Centers | 2019 Properties | Discontinued operations
Real Estate [Line Items]
Contract sales price					$ 23,500
(Loss) gain on sale					$ (3,506)
Area of property (sq ft) | ft²					330
1776 G Street | Office | 2019 Properties | Disposal group, not discontinued operations
Real Estate [Line Items]
Contract sales price				$ 129,500
(Loss) gain on sale				$ 61,007
Area of property (sq ft) | ft²				262
Braddock Metro Center | Office | 2018 Properties | Disposal group, not discontinued operations
Real Estate [Line Items]
Contract sales price										$ 93,000
(Loss) gain on sale										$ 0
Area of property (sq ft) | ft²										356
Impairment of real estate																						$ 9,100
2445 M Street | Office | 2018 Properties | Disposal group, not discontinued operations
Real Estate [Line Items]
Contract sales price									$ 101,600									$ 100,000
(Loss) gain on sale									$ 2,495
Area of property (sq ft) | ft²									292									292
Impairment of real estate																		$ 1,900				$ 24,100

Real Estate - Discontinued Oper

Real Estate - Discontinued Operations Results of Retail Portfolio (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Results of Discontinued Operations
Loss on extinguishment of debt		$ 0	$ (764)	$ 0
Gain on sale of real estate	$ 339,000	0	339,024	0
Income from discontinued operations		$ 0	$ 354,418	$ 24,477
Discontinued operations, basic (in dollars per share)		$ 0	$ 4.39	$ 0.31
Discontinued operations, diluted (in dollars per share)		$ 0	$ 4.39	$ 0.31
Capital expenditures			$ 809	$ 2,138
Retail Portfolio | Discontinued operations
Results of Discontinued Operations
Real estate rental revenue			28,200	45,160
Real estate expenses			(6,803)	(10,638)
Depreciation and amortization			(4,926)	(9,402)
Interest expense			(313)	(643)
Loss on extinguishment of debt			(764)	0
Gain on sale of real estate			339,024	0
Income from discontinued operations			$ 354,418	$ 24,477

Lease Accounting - Schedule of

Lease Accounting - Schedule of Future Minimum Rental Income (Details) $ in Thousands	Dec. 31, 2020USD ($)
Future Minimum rental income
2021	$ 122,062
2022	109,939
2023	93,467
2024	80,793
2025	63,923
Thereafter	215,443
Total	$ 685,627

Lease Accounting - Leasing as a

Lease Accounting - Leasing as a Lessor Narrative (Details)	Dec. 31, 2020
Multifamily Properties
Lessor, Lease, Description [Line Items]
Lessor operating lease term (in years)	1 year

Lease Accounting - Leasing as_2

Lease Accounting - Leasing as a Lessee Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2019
Leases [Abstract]
Lessee operating lease term (in years)	50 years
Straight-line rental expense	$ 300	$ 300	$ 300
Variable rental payments	800	900	$ 900
Right-of-use asset				$ 4,200
Lease liability	3,732			$ 4,200
Operating lease discount rate (percent)				5.90%
Right-of-use asset and lease liability amortization	$ 200	$ 300
Right-of-use asset, statement of financial position line item				us-gaap:RentalProperties
Lease liability, statement of financial position line item	us-gaap:AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent			us-gaap:AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent

Lease Accounting - Schedule o_2

Lease Accounting - Schedule of Obligations for Future Minimum Payments on Operating Ground Lease (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Jan. 01, 2019
Obligations for Future Minimum Payments on Operating Ground Lease
2021	$ 260
2022	260
2023	260
2024	260
2025	260
Thereafter	11,635
Total minimum payments due	12,935
Imputed interest	(9,203)
Lease liability	$ 3,732	$ 4,200

Mortgage Note Payable - Narrati

Mortgage Note Payable - Narrative (Details)	1 Months Ended	3 Months Ended	12 Months Ended
	Jan. 31, 2020USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)debt_instrument	Dec. 31, 2018USD ($)
Debt Instrument [Line Items]
Gain on extinguishment of debt		$ (300,000)	$ (34,000)	$ 0	$ (1,178,000)
Mortgage notes payable, net		0	0	47,074,000
Income producing property, at cost		2,983,617,000	2,983,617,000	$ 2,959,222,000
Mortgages
Debt Instrument [Line Items]
Mortgage notes payable, net		$ 0	$ 0
Number of mortgage notes | debt_instrument				1
Yale West | Mortgages
Debt Instrument [Line Items]
Prepayment of mortgage note	$ 45,600,000
Gain on extinguishment of debt	500,000
Write-off of unamortized premium	1,400,000
Prepayment penalty	$ 900,000
Income producing property, at cost				$ 77,400,000

Mortgage Note Payable - Outstan

Mortgage Note Payable - Outstanding Mortgage Notes Payable (Details) - Mortgages $ in Thousands	Dec. 31, 2019USD ($)
Debt Instrument [Line Items]
Effective interest rate (percent)	3.75%
Total principal	$ 45,654
Premiums and discounts, net	1,470
Deferred issuance costs, net	(50)
Total, net	$ 47,074

Unsecured Lines of Credit Pay_3

Unsecured Lines of Credit Payable - Narrative (Details)	Dec. 31, 2020USD ($)	Mar. 31, 2018USD ($)extension_option	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Mar. 29, 2018USD ($)	Dec. 31, 2017USD ($)	Jul. 22, 2016USD ($)	Sep. 15, 2015USD ($)
Line of Credit Facility [Line Items]
Revolving credit facility borrowing capacity	$ 700,000,000		$ 700,000,000	$ 700,000,000	$ 700,000,000
Repayments of outstanding borrowings			$ 14,000,000	132,000,000
U.S. covered terrorism losses (percent)	0.85		0.85
Insurance provider covered terrorism loss (percent)	0.10		0.10
Aggregate insured losses from all insurers in covered terrorism metric			$ 100,000,000,000
Credit Agreement
Line of Credit Facility [Line Items]
Credit agreement, aggregate maximum borrowing capacity including accordion feature		$ 1,500,000,000
2015 Term Loan
Line of Credit Facility [Line Items]
Debt instrument face amount									$ 150,000,000
2015 Term Loan | Interest Rate Swap
Line of Credit Facility [Line Items]
Derivative notional amount				$ 150,000,000					$ 150,000,000
Derivative fixed interest rate (percent)									2.72%
2016 Term Loan
Line of Credit Facility [Line Items]
Debt instrument face amount								$ 150,000,000
2016 Term Loan | Interest Rate Swap
Line of Credit Facility [Line Items]
Derivative notional amount								$ 150,000,000
Derivative fixed interest rate (percent)								2.86%
2018 Term Loan
Line of Credit Facility [Line Items]
Debt instrument face amount						$ 250,000,000
2018 Term Loan | Interest Rate Swap
Line of Credit Facility [Line Items]
Derivative fixed interest rate (percent)						2.87%
2018 Term Loan A | Interest Rate Swap
Line of Credit Facility [Line Items]
Derivative notional amount	$ 150,000,000		$ 150,000,000			$ 150,000,000
Derivative fixed interest rate (percent)	2.31%		2.31%			2.31%
2018 Term Loan B
Line of Credit Facility [Line Items]
Debt instrument face amount						$ 100,000,000
2018 Term Loan B | Interest Rate Swap
Line of Credit Facility [Line Items]
Derivative notional amount	$ 100,000,000		$ 100,000,000			$ 100,000,000
Derivative fixed interest rate (percent)	3.71%		3.71%			3.71%
Term loan | 2015 Term Loan
Line of Credit Facility [Line Items]
Debt instrument face amount		150,000,000
Term loan | 2016 Term Loan
Line of Credit Facility [Line Items]
Debt instrument face amount							$ 150,000,000
Term loan | 2018 Term Loan
Line of Credit Facility [Line Items]
Debt instrument face amount		250,000,000
All-in fixed interest rate (percent)	2.87%		2.87%
Term loan | 2018 Term Loan | LIBOR | Minimum
Line of Credit Facility [Line Items]
Basis spread on variable rate (percent)			0.85%
Term loan | 2018 Term Loan | LIBOR | Maximum
Line of Credit Facility [Line Items]
Basis spread on variable rate (percent)			1.75%
Term loan | 2018 Term Loan | Base Rate | Minimum
Line of Credit Facility [Line Items]
Basis spread on variable rate (percent)			0.00%
Term loan | 2018 Term Loan | Base Rate | Maximum
Line of Credit Facility [Line Items]
Basis spread on variable rate (percent)			0.75%
Revolving Credit Facility
Line of Credit Facility [Line Items]
Revolving credit facility borrowing capacity	$ 700,000,000	$ 700,000,000	$ 700,000,000
Debt instrument term (in years)		4 years
Number of extensions allowed | extension_option		2
Term of allowable extension (in years)		6 months
Repayments of outstanding borrowings		$ 100,000,000	$ 746,000,000
Facility fee (percent)	0.20%
One-month LIBOR (percent)	0.14%		0.14%
Revolving Credit Facility | Minimum
Line of Credit Facility [Line Items]
Facility fee (percent)			0.10%
Revolving Credit Facility | Maximum
Line of Credit Facility [Line Items]
Facility fee (percent)			0.30%
Revolving Credit Facility | LIBOR
Line of Credit Facility [Line Items]
Basis spread on variable rate (percent)	1.00%
Base rate component, spread on variable rate (percent)			1.00%
Revolving Credit Facility | LIBOR | Minimum
Line of Credit Facility [Line Items]
Basis spread on variable rate (percent)			0.775%
Revolving Credit Facility | LIBOR | Maximum
Line of Credit Facility [Line Items]
Basis spread on variable rate (percent)			1.55%
Revolving Credit Facility | Base Rate | Minimum
Line of Credit Facility [Line Items]
Basis spread on variable rate (percent)			0.00%
Revolving Credit Facility | Base Rate | Maximum
Line of Credit Facility [Line Items]
Basis spread on variable rate (percent)			0.55%
Revolving Credit Facility | Federal Funds Rate
Line of Credit Facility [Line Items]
Base rate component, spread on variable rate (percent)			0.50%

Unsecured Lines of Credit Pay_4

Unsecured Lines of Credit Payable - Revolving Credit Facility Unused and Available Credit (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Line of Credit Facility [Line Items]
Committed capacity	$ 700,000,000	$ 700,000,000	$ 700,000,000
Borrowings outstanding	(42,000,000)	(56,000,000)	$ (188,000,000)
Revolving Credit Facility
Line of Credit Facility [Line Items]
Committed capacity	700,000,000			$ 700,000,000
Borrowings outstanding	(42,000,000)	$ (56,000,000)
Unused and available	$ 658,000,000

Unsecured Lines of Credit Pay_5

Unsecured Lines of Credit Payable - Borrowings and Repayments (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Line of Credit [Roll Forward]
Balance, beginning		$ 56,000	$ 188,000
Borrowings				$ 22,000
Repayments		(14,000)	(132,000)
Balance, ending		42,000	56,000	$ 188,000
Revolving Credit Facility
Line of Credit [Roll Forward]
Balance, beginning		56,000
Borrowings		732,000
Repayments	$ (100,000)	(746,000)
Balance, ending		$ 42,000	$ 56,000

Unsecured Lines of Credit Pay_6

Unsecured Lines of Credit Payable - Recognized Interest Expense and Facility Fees (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Debt Disclosure [Abstract]
Interest expense (excluding facility fees)	$ 3,035	$ 6,554	$ 6,843
Facility fees	$ 1,423	$ 1,400	$ 1,371

Unsecured Lines of Credit Pay_7

Unsecured Lines of Credit Payable - Information Related to Revolving Credit Facility (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Debt Disclosure [Abstract]
Total revolving credit facilities	$ 700,000,000	$ 700,000,000	$ 700,000,000
Borrowings outstanding	42,000,000	56,000,000	188,000,000
Weighted average daily borrowings during the year	204,809,000	196,074,000	230,934,000
Maximum daily borrowings during the year	$ 456,000,000	$ 300,000,000	$ 429,000,000
Weighted average interest rate during the year	1.48%	3.34%	2.96%
Weighted average interest rate on borrowings outstanding	1.15%	2.73%	3.52%

Notes Payable - Unsecured Notes

Notes Payable - Unsecured Notes and Term Loans Outstanding (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Nov. 30, 2019
Unsecured notes and term loans
Debt Instrument [Line Items]
Total principal	$ 950,000,000	$ 1,000,000,000
Premiums and discounts, net	(456,000)	(797,000)
Deferred issuance costs, net	(4,174,000)	(2,481,000)
Total, net	945,370,000	996,722,000
Principal amounts due prior to maturity	$ 0
10 Year Unsecured Notes 4.95%
Debt Instrument [Line Items]
Coupon/Stated rate (percent)			4.95%
10 Year Unsecured Notes 4.95% | Unsecured notes and term loans
Debt Instrument [Line Items]
Coupon/Stated rate (percent)	4.95%
Effective interest rate (percent)	5.05%
Total principal	$ 0	250,000,000
Payoff Date/Maturity Date	Oct. 1, 2020
2015 Term Loan | Unsecured notes and term loans
Debt Instrument [Line Items]
Effective interest rate (percent)	2.72%
Total principal	$ 0	150,000,000
Payoff Date/Maturity Date	Mar. 15, 2021
2015 Term Loan | Unsecured notes and term loans | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate (percent)	1.10%
10 Year Unsecured Notes 3.95% | Unsecured notes and term loans
Debt Instrument [Line Items]
Coupon/Stated rate (percent)	3.95%
Effective interest rate (percent)	4.02%
Total principal	$ 300,000,000	300,000,000
Payoff Date/Maturity Date	Oct. 15, 2022
2018 Term Loan | Unsecured notes and term loans
Debt Instrument [Line Items]
Effective interest rate (percent)	2.87%
Total principal	$ 250,000,000	250,000,000
Payoff Date/Maturity Date	Jul. 21, 2023
2018 Term Loan | Unsecured notes and term loans | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate (percent)	1.10%
30 Year Unsecured Notes 7.25% | Unsecured notes and term loans
Debt Instrument [Line Items]
Coupon/Stated rate (percent)	7.25%
Effective interest rate (percent)	7.36%
Total principal	$ 50,000,000	50,000,000
Payoff Date/Maturity Date	Feb. 25, 2028
Green Bonds | Unsecured notes and term loans
Debt Instrument [Line Items]
Coupon/Stated rate (percent)	3.44%
Effective interest rate (percent)	4.09%
Total principal	$ 350,000,000	$ 0
Payoff Date/Maturity Date	Dec. 29, 2030

Notes Payable - Narrative (Deta

Notes Payable - Narrative (Details) - USD ($)

Sep. 30, 2020

Sep. 29, 2020

May 05, 2020

Apr. 30, 2019

Apr. 30, 2020

Nov. 30, 2019

Dec. 31, 2020

Sep. 30, 2019

Sep. 30, 2019

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

Mar. 31, 2018

Sep. 15, 2015

Short-term Debt [Line Items]

Repayment of borrowings

$ 300,000,000

$ 450,000,000

$ 150,000,000

Loss on extinguishment of debt

$ (300,000)

(34,000)

0

$ (1,178,000)

10 Year Unsecured Notes 4.95%

Short-term Debt [Line Items]

Stated interest rate (percent)

4.95%

Debt instrument term (in years)

10 years

Debt instrument face amount

$ 250,000,000

Green Bonds

Short-term Debt [Line Items]

Debt instrument term (in years)

10 years

2015 Term Loan

Short-term Debt [Line Items]

Debt instrument face amount

$ 150,000,000

Notes payable | 10 Year Unsecured Notes 4.95%

Short-term Debt [Line Items]

Repayment of borrowings

$ 250,000,000

Stated interest rate (percent)

4.95%

Debt instrument term (in years)

10 years

Notes payable | Green Bonds

Short-term Debt [Line Items]

Stated interest rate (percent)

3.44%

Debt instrument term (in years)

10 years

Debt instrument face amount

$ 350,000,000

Effective interest rate (percent)

4.09%

Debt issuance costs

$ 2,600,000

Term loan | 2015 Term Loan

Short-term Debt [Line Items]

Repayment of borrowings

150,000,000

Debt instrument face amount

$ 150,000,000

Unsecured notes and term loans

Short-term Debt [Line Items]

Debt issuance costs

$ 4,174,000

$ 4,174,000

$ 2,481,000

Unsecured notes and term loans | 10 Year Unsecured Notes 4.95%

Short-term Debt [Line Items]

Stated interest rate (percent)

4.95%

4.95%

Maturity date

Oct. 1, 2020

Effective interest rate (percent)

5.05%

5.05%

Unsecured notes and term loans | Green Bonds

Short-term Debt [Line Items]

Stated interest rate (percent)

3.44%

3.44%

Maturity date

Dec. 29, 2030

Effective interest rate (percent)

4.09%

4.09%

Unsecured notes and term loans | 2015 Term Loan

Short-term Debt [Line Items]

Maturity date

Mar. 15, 2021

Effective interest rate (percent)

2.72%

2.72%

Unsecured notes and term loans | 2015 Term Loan | LIBOR

Short-term Debt [Line Items]

Basis spread on variable rate (percent)

1.10%

Term loan | 2020 Term Loan

Short-term Debt [Line Items]

Debt instrument term (in years)

1 year

Debt instrument face amount

$ 150,000,000

Maturity date

May 5, 2021

Extension term (in years)

1 year

Repayment of borrowings

$ 150,000,000

Term loan | 2020 Term Loan | LIBOR

Short-term Debt [Line Items]

Basis spread on variable rate (percent)

1.50%

Term loan | 2020 Term Loan | LIBOR | Minimum

Short-term Debt [Line Items]

Basis spread on variable rate (percent)

0.50%

Term loan | 2019 Term Loan

Short-term Debt [Line Items]

Debt instrument term (in years)

6 months

Debt instrument face amount

$ 450,000,000

Maturity date

Oct. 30, 2019

Extension term (in years)

6 months

Repayment of borrowings

$ 450,000,000

Term loan | 2019 Term Loan | LIBOR

Short-term Debt [Line Items]

Base rate component, spread on variable rate (percent)

1.00%

Basis point component of interest rate at Company's election (percent)

1.00%

Term loan | 2019 Term Loan | LIBOR | Minimum

Short-term Debt [Line Items]

Basis spread on variable rate (percent)

0.75%

Term loan | 2019 Term Loan | LIBOR | Maximum

Short-term Debt [Line Items]

Basis spread on variable rate (percent)

1.65%

Term loan | 2019 Term Loan | Base Rate | Minimum

Short-term Debt [Line Items]

Basis spread on variable rate (percent)

0.00%

Term loan | 2019 Term Loan | Base Rate | Maximum

Short-term Debt [Line Items]

Basis spread on variable rate (percent)

0.65%

Term loan | 2019 Term Loan | Federal Funds Rate

Short-term Debt [Line Items]

Base rate component, spread on variable rate (percent)

0.50%

Notes Payable - Required Princi

Notes Payable - Required Principal Payments on Unsecured Notes and Term Loans (Details) - Unsecured notes and term loans - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Required Principal Payments [Abstract]
2021	$ 0
2022	300,000
2023	250,000
2024	0
2025	0
Thereafter	400,000
Total principal	$ 950,000	$ 1,000,000

Derivative Instruments - Narrat

Derivative Instruments - Narrative (Details)

Oct. 02, 2020USD ($)

Sep. 30, 2020USD ($)

Sep. 29, 2020USD ($)

Dec. 31, 2020USD ($)

Apr. 30, 2020USD ($)

Nov. 30, 2019USD ($)arrangement

Dec. 31, 2020USD ($)

Dec. 31, 2019USD ($)

Dec. 31, 2018USD ($)

Mar. 29, 2018USD ($)arrangement

Jul. 22, 2016USD ($)arrangement

Sep. 15, 2015USD ($)arrangement

Derivative [Line Items]

Repayment of borrowings

$ 300,000,000

$ 450,000,000

$ 150,000,000

Loss on interest rate derivatives

$ 600,000

560,000

0

$ 0

Interest Rate Swap

Derivative [Line Items]

Fair value of derivative liabilities

10,300,000

10,300,000

Estimated amount to be reclassified within next twelve months as an increase to interest expense

6,000,000

Fair value of derivative assets

0

0

2015 Term Loan

Derivative [Line Items]

Debt instrument face amount

$ 150,000,000

2015 Term Loan | Interest Rate Swap

Derivative [Line Items]

Number of derivative arrangements | arrangement

2

Derivative notional amount

150,000,000

$ 150,000,000

All-in fixed interest rate (percent)

2.72%

Aggregate notional amount of terminated agreements

150,000,000

2016 Term Loan

Derivative [Line Items]

Debt instrument face amount

$ 150,000,000

2016 Term Loan | Interest Rate Swap

Derivative [Line Items]

Number of derivative arrangements | arrangement

2

Derivative notional amount

$ 150,000,000

All-in fixed interest rate (percent)

2.86%

2018 Term Loan

Derivative [Line Items]

Debt instrument face amount

$ 250,000,000

2018 Term Loan | Interest Rate Swap

Derivative [Line Items]

All-in fixed interest rate (percent)

2.87%

2018 Term Loan A | Interest Rate Swap

Derivative [Line Items]

Derivative notional amount

$ 150,000,000

$ 150,000,000

$ 150,000,000

All-in fixed interest rate (percent)

2.31%

2.31%

2.31%

2018 Term Loan B

Derivative [Line Items]

Debt instrument face amount

$ 100,000,000

2018 Term Loan B | Interest Rate Swap

Derivative [Line Items]

Number of derivative arrangements | arrangement

4

Derivative notional amount

$ 100,000,000

$ 100,000,000

$ 100,000,000

All-in fixed interest rate (percent)

3.71%

3.71%

3.71%

Forward Swaps for future fixed-rate debt | Interest Rate Swap

Derivative [Line Items]

Number of derivative arrangements | arrangement

4

Derivative notional amount

$ 200,000,000

$ 200,000,000

Fair value of derivative liabilities

$ 20,400,000

Repayment of derivative liability

$ 20,400,000

10 Year Unsecured Notes 4.95%

Derivative [Line Items]

Debt instrument face amount

$ 250,000,000

Stated interest rate (percent)

4.95%

Debt instrument term (in years)

10 years

10 Year Unsecured Notes 4.95% | Notes payable

Derivative [Line Items]

Stated interest rate (percent)

4.95%

Debt instrument term (in years)

10 years

Repayment of borrowings

$ 250,000,000

Green Bonds

Derivative [Line Items]

Debt instrument term (in years)

10 years

Green Bonds | Notes payable

Derivative [Line Items]

Debt instrument face amount

$ 350,000,000

Stated interest rate (percent)

3.44%

Debt instrument term (in years)

10 years

Derivative Instruments - Fair V

Derivative Instruments - Fair Value of Interest Rate Swaps (Details) - Interest Rate Swap - USD ($)	Dec. 31, 2020	Dec. 31, 2019	Nov. 30, 2019	Mar. 29, 2018	Sep. 15, 2015
Derivative [Line Items]
Derivative Assets (Liabilities)	$ (10,255,000)	$ 1,823,000
2015 Term Loan
Derivative [Line Items]
Aggregate Notional Amount		150,000,000			$ 150,000,000
2015 Term Loan | Accounts payable and other liabilities
Derivative [Line Items]
Derivative Assets (Liabilities)	0	(62,000)
2018 Term Loan A
Derivative [Line Items]
Aggregate Notional Amount	150,000,000			$ 150,000,000
2018 Term Loan A | Accounts payable and other liabilities
Derivative [Line Items]
Derivative Assets (Liabilities)	(4,009,000)
2018 Term Loan A | Prepaid expenses and other assets
Derivative [Line Items]
Derivative Assets (Liabilities)		1,825,000
2018 Term Loan B
Derivative [Line Items]
Aggregate Notional Amount	100,000,000			$ 100,000,000
2018 Term Loan B | Accounts payable and other liabilities
Derivative [Line Items]
Derivative Assets (Liabilities)	(6,246,000)	(3,664,000)
Forward Swaps for future fixed-rate debt
Derivative [Line Items]
Aggregate Notional Amount		200,000,000	$ 200,000,000
Forward Swaps for future fixed-rate debt | Prepaid expenses and other assets
Derivative [Line Items]
Derivative Assets (Liabilities)	$ 0	$ 3,724,000

Derivative Instruments - Unreal

Derivative Instruments - Unrealized Gains and Losses and Reclassification (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Unrealized (loss) gain on interest rate derivatives	$ (33,025)	$ (8,016)	$ 420
Loss reclassified from Accumulated other comprehensive income (loss) into interest expense	$ 79	$ 0	$ 0

Fair Value Disclosures - Assets

Fair Value Disclosures - Assets and Liabilities Measured at Fair Value (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Interest Rate Swap
Assets:
Interest rate swaps	$ 0
Liabilities:
Interest rate swaps	(10,300,000)
Recurring | SERP
Assets:
SERP	2,433,000	$ 1,792,000
Recurring | Interest Rate Swap
Assets:
Interest rate swaps	0	5,549,000
Liabilities:
Interest rate swaps	(10,255,000)	(3,726,000)
Recurring | Level 1 | SERP
Assets:
SERP	0	0
Recurring | Level 1 | Interest Rate Swap
Assets:
Interest rate swaps	0	0
Liabilities:
Interest rate swaps	0	0
Recurring | Level 2 | SERP
Assets:
SERP	2,433,000	1,792,000
Recurring | Level 2 | Interest Rate Swap
Assets:
Interest rate swaps	0	5,549,000
Liabilities:
Interest rate swaps	(10,255,000)	(3,726,000)
Recurring | Level 3 | SERP
Assets:
SERP	0	0
Recurring | Level 3 | Interest Rate Swap
Assets:
Interest rate swaps	0	0
Liabilities:
Interest rate swaps	$ 0	$ 0

Fair Value Disclosures - Carryi

Fair Value Disclosures - Carrying Values and Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	$ 7,700	$ 12,939
Restricted cash	603	1,812
Mortgage notes payable	0	47,074
Line of credit payable	42,000	56,000
Notes payable	945,370	996,722
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	7,700	12,939
Restricted cash	603	1,812
Mortgage notes payable	0	47,899
Line of credit payable	42,000	56,000
Notes payable	$ 978,678	$ 1,022,937

Stock Based Compensation - Narr

Stock Based Compensation - Narrative (Details)	12 Months Ended
	Dec. 31, 2020USD ($)employment_yearshares	Dec. 31, 2019USD ($)shares	Dec. 31, 2018USD ($)shares	Dec. 31, 2017shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense | $	$ 7,900,000	$ 7,700,000	$ 6,700,000
Capitalized stock-based compensation expense | $	400,000	200,000	300,000
Trustee
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of share-based compensation for each trustee | $	$ 100,000	$ 100,000	$ 100,000
Restricted share awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognition period for compensation expense	21 months
One-time equity award granted (shares) | shares	285,101	213,782	304,087
Retirement age with 20 years employment | employment_year	55
Years of employment for retirement age metric	20 years
Retirement age | employment_year	65
Fair value of restricted share units vested | $	$ 6,600,000	$ 6,500,000	$ 6,100,000
Compensation costs not yet recognized | $	$ 7,000,000
Restricted share awards | Chief executive officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
One-time equity award granted (shares) | shares				100,000
Percentage of equity award that vests on fifth anniversary of grant date				100.00%
Washington Real Estate Investment Trust 2016 Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (in shares) | shares	2,400,000
Incentive plan, period in effect (in years)	10 years
Options outstanding (in shares) | shares	0	0
Washington Real Estate Investment Trust 2007 Omnibus Long-Term Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (in shares) | shares		2,000,000
Officer STIP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate weighting of performance and time-based measures (percent)	100.00%
Officer LTIP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate weighting of performance and time-based measures (percent)	100.00%
Officer LTIP | Time-based award
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Vesting percentage per year over three-year vesting period (percent)	33.33%
Officer LTIP | Performance award
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of awards that vest immediately after performance period	100.00%
Prior STIP | Executive officers
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards payable in cash (percent)		50.00%
Awards payable in restricted shares (percent)		50.00%
Performance period (in years)		1 year
Prior STIP | Non-executive officer and staff
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incentive plan bonuses payable in cash (percent)		100.00%
Prior STIP | Restricted share awards | Executive officers
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		3 years
Performance period (in years)		1 year
Prior LTIP | Executive officers
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards payable in unrestricted shares (percent)	75.00%	75.00%
Awards payable in restricted shares (percent)	25.00%	25.00%
Performance period (in years)	3 years	3 years	3 years	3 years
Performance evaluated on absolute TSR			50.00%	50.00%
Performance evaluated on relative TSR			50.00%	50.00%
Performance evaluated on relative TSR to defined population of peer companies	50.00%	50.00%	50.00%	50.00%
Performance evaluated on relative TSR to FTSE NAREIT Diversified Index	50.00%	50.00%	50.00%
Prior LTIP | Executive officers | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total award opportunities as a percentage of base salary			80.00%
Grant date fair value as a percentage of base salary for awards evaluated on relative TSR to defined population of peer companies	20.00%	35.00%
Grant date fair value as a percentage of base salary for awards evaluated on on relative TSR to FTSE NAREIT Diversified Index	22.00%	39.00%
Grant date fair value as a percentage of base salary for awards evaluated on on relative TSR			31.00%
Grant date fair value as a percentage of base salary for awards evaluated on on absolute TSR			35.00%
Prior LTIP | Executive officers | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total award opportunities as a percentage of base salary			150.00%
Grant date fair value as a percentage of base salary for awards evaluated on relative TSR to defined population of peer companies	42.00%	68.00%
Grant date fair value as a percentage of base salary for awards evaluated on on relative TSR to FTSE NAREIT Diversified Index	46.00%	74.00%
Grant date fair value as a percentage of base salary for awards evaluated on on relative TSR			60.00%
Grant date fair value as a percentage of base salary for awards evaluated on on absolute TSR			68.00%
Prior LTIP | Unrestricted share awards | Executive officers
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period (in years)			3 years
Recognition period for compensation expense	3 years
Prior LTIP | Restricted share awards | Executive officers
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period			1 year
Performance period (in years)			3 years
Recognition period for compensation expense	4 years
LTIP for non-executive officers and staff
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Performance period (in years)	3 years

Stock Based Compensation - Offi

Stock Based Compensation - Officer STIP and LTIP Performance Metrics (Details) - Performance award	Dec. 31, 2020
Officer STIP | President and Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award as percentage of base salary, threshold performance goal (percent)	63.00%
Award as percentage of base salary, target performance goal (percent)	125.00%
Award as percentage of base salary, high performance goal (percent)	188.00%
Officer STIP | Executive Vice President
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award as percentage of base salary, threshold performance goal (percent)	48.00%
Award as percentage of base salary, target performance goal (percent)	93.00%
Award as percentage of base salary, high performance goal (percent)	160.00%
Officer STIP | Senior Vice President
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award as percentage of base salary, threshold performance goal (percent)	35.00%
Award as percentage of base salary, target performance goal (percent)	65.00%
Award as percentage of base salary, high performance goal (percent)	115.00%
Officer LTIP | President and Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award as percentage of base salary, threshold performance goal (percent)	198.00%
Award as percentage of base salary, target performance goal (percent)	275.00%
Award as percentage of base salary, high performance goal (percent)	440.00%
Officer LTIP | Executive Vice President
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award as percentage of base salary, threshold performance goal (percent)	143.00%
Award as percentage of base salary, target performance goal (percent)	200.00%
Award as percentage of base salary, high performance goal (percent)	295.00%
Officer LTIP | Senior Vice President
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award as percentage of base salary, threshold performance goal (percent)	100.00%
Award as percentage of base salary, target performance goal (percent)	143.00%
Award as percentage of base salary, high performance goal (percent)	207.00%

Stock Based Compensation - Assu

Stock Based Compensation - Assumptions for LTIP Awards (Details) - Officer LTIP and Prior LTIP - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility (percent)	17.50%	18.10%	17.90%
Risk-free interest rate (percent)	1.40%	2.40%	2.40%
Expected term (in years)	3 years
Share price at grant date (in dollars per share)	$ 31.50	$ 23	$ 26.06
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)		3 years	3 years
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)		4 years	4 years

Stock Based Compensation - Rest

Stock Based Compensation - Restricted Share Awards with Performance and Service Conditions (Details) - Restricted share awards - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Restricted share awards, excluding those subject to market conditions
Unvested, beginning (in shares)	269,383	311,010	236,694
Granted (in shares)	285,101	213,782	304,087
Vested during year (in shares)	(239,033)	(236,013)	(224,150)
Forfeited (in shares)	(8,456)	(19,396)	(5,621)
Unvested, ending (in shares)	306,995	269,383	311,010
Weighted Average Grant Date Fair Value
Unvested, beginning (in dollars per share)	$ 28.45	$ 29.07	$ 27.96
Granted (in dollars per share)	30.39	26.26	25.98
Vested during year (in dollars per share)	27.54	27.43	27.40
Forfeited (in dollars per share)	28.35	26.60	29.43
Unvested, ending (in dollars per share)	$ 30.96	$ 28.45	$ 29.07

Stock Based Compensation - Re_2

Stock Based Compensation - Restricted and Unrestricted Shares with Market Conditions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Restricted Relative Peer TSR
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant Date Fair Value		$ 184	$ 203
Restricted Absolute/Index TSR
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant Date Fair Value		201	230
Unrestricted Relative Peer TSR
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant Date Fair Value	$ 510	552	608
Unrestricted Absolute/Index TSR
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant Date Fair Value	$ 565	$ 602	$ 690
Absolute/Index TSR
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance evaluated on relative TSR to defined population of peer companies	50.00%	50.00%	50.00%
Performance evaluated on relative TSR to FTSE NAREIT Diversified Index	50.00%	50.00%	50.00%
2020 Awards | Unrestricted Relative Peer TSR
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested Value	$ 355
2020 Awards | Unrestricted Absolute/Index TSR
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested Value	$ 393
Performance period (in years)	3 years
2019 and 2018 Awards | Restricted Absolute/Index TSR
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period (in years)		3 years
Percentage of total award		25.00%
Award vesting period		1 year
2019 and 2018 Awards | Unrestricted Absolute/Index TSR
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period (in years)		3 years
Percentage of total award		75.00%
2019 Awards | Restricted Relative Peer TSR
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested Value	$ 92
2019 Awards | Restricted Absolute/Index TSR
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested Value	100
2019 Awards | Unrestricted Relative Peer TSR
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested Value	184
2019 Awards | Unrestricted Absolute/Index TSR
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested Value	201
2018 Awards | Restricted Relative Peer TSR
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested Value	42
2018 Awards | Restricted Absolute/Index TSR
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested Value	48
2018 Awards | Unrestricted Relative Peer TSR
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested Value	0
2018 Awards | Unrestricted Absolute/Index TSR
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested Value	$ 0

Other Benefit Plans (Details)

Other Benefit Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
401I(k) plan contributions by employer	$ 0.4	$ 0.5	$ 0.5
Liability, Other Postretirement Defined Benefit Plan, Noncurrent	0.7	0.9
Pension and Other Postretirement Benefits Cost (Reversal of Cost)	0.2	0.2	$ 0.3
Officer
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Accrued benefit liability	$ 2.4	$ 1.8

Earnings Per Common Share (Deta

Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Numerator:
(Loss) income from continuing operations	$ (11,037)	$ (956)	$ (5,406)	$ 1,719	$ 54,198	$ (8,432)	$ (6,191)	$ (10,443)	$ (15,680)	$ 29,132	$ 1,153
Allocation of distributed earnings to unvested restricted share awards to continuing operations									(545)	(125)	(526)
Adjusted (loss) income from continuing operations									(16,225)	29,007	627
Income from discontinued operations, including gain on sale of real estate									0	354,418	24,477
Allocation of earnings from discontinued operations to unvested restricted share awards									0	(1,837)	0
Adjusted income from discontinued operations									0	352,581	24,477
Adjusted net (loss) income									$ (16,225)	$ 381,588	$ 25,104
Denominator:
Weighted average shares outstanding – basic (in shares)									82,348	80,257	78,960
Effect of dilutive securities:
Operating partnership units									0	12	12
Employee restricted share awards									0	66	70
Weighted average shares outstanding – diluted (in shares)									82,348	80,335	79,042
Earnings per common share, basic:
Continuing operations, basic (in dollars per share)	$ (0.13)	$ (0.01)	$ (0.07)	$ 0.02	$ 0.66	$ (0.10)	$ (0.08)	$ (0.13)	$ (0.20)	$ 0.36	$ 0.01
Discontinued operations, basic (in dollars per share)									0	4.39	0.31
Net income attributable to the controlling interests per share (in dollars per share)	(0.13)	(0.01)	(0.07)	0.02	0.66	4.14	0.01	(0.06)	(0.20)	4.75	0.32
Earnings per common share, diluted:
Continuing operations, diluted (in dollars per share)	(0.13)	(0.01)	(0.07)	0.02	0.66	(0.10)	(0.08)	(0.13)	(0.20)	0.36	0.01
Discontinued operations, diluted (in dollars per share)									0	4.39	0.31
Net income attributable to the controlling interests per share (in dollars per share)	$ (0.13)	$ (0.01)	$ (0.07)	$ 0.02	$ 0.66	$ 4.14	$ 0.01	$ (0.06)	(0.20)	4.75	0.32
Dividends declared per common share (in dollars per share)									$ 1.20	$ 1.20	$ 1.20

Segment Information - Segments

Segment Information - Segments (Details)	12 Months Ended
	Dec. 31, 2020propertysegment	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Number of reportable segments | segment	2
Number of properties that do not meet criteria for reportable segment | property	8
Reportable segments | Multifamily
Segment Reporting Information [Line Items]
Real estate rental revenue as a percentage of total	0.49	0.41	0.33
Percentage of total income producing real estate assets	0.54	0.50
Reportable segments | Office
Segment Reporting Information [Line Items]
Real estate rental revenue as a percentage of total	0.45	0.53	0.61
Percentage of total income producing real estate assets	0.41	0.45
Corporate and other
Segment Reporting Information [Line Items]
Real estate rental revenue as a percentage of total	0.06	0.06	0.06
Percentage of total income producing real estate assets	0.05	0.05

Segment Information - Financial

Segment Information - Financial Information by Segment (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reconciliation [Abstract]
Real estate rental revenue		$ 71,229	$ 73,227	$ 72,870	$ 76,792	$ 80,667	$ 80,259	$ 76,820	$ 71,434	$ 294,118	$ 309,180	$ 291,730
Real estate expenses										112,909	115,580	105,592
Net operating income										181,209	193,600	186,138
Depreciation and amortization										(120,030)	(136,253)	(111,826)
General and administrative										(23,951)	(26,068)	(22,089)
Real estate impairment										0	(8,374)	(1,886)
Interest expense										(37,305)	(53,734)	(50,501)
Loss on interest rate derivatives	$ (600)									(560)	0	0
Loss on extinguishment of debt		(300)								(34)	0	(1,178)
(Loss) gain on sale of real estate		(7,500)		$ (7,500)		61,000		$ (1,000)		(15,009)	59,961	2,495
Income from operations of properties sold or held for sale										0	16,158	24,477
Gain on sale of real estate							$ 339,000			0	339,024	0
Loss on extinguishment of debt										0	(764)	0
Net (loss) income										(15,680)	383,550	25,630
Capital expenditures										58,317	68,947	72,033
Total assets	2,409,818	2,409,818				2,628,328				2,409,818	2,628,328	2,417,104
Reportable segments | Office
Segment Reconciliation [Abstract]
Real estate rental revenue										132,327	164,059	178,474
Real estate expenses										49,452	60,923	63,321
Net operating income										82,875	103,136	115,153
Capital expenditures										31,148	38,634	42,019
Total assets	940,069	940,069				1,134,147				940,069	1,134,147	1,248,673
Reportable segments | Multifamily
Segment Reconciliation [Abstract]
Real estate rental revenue										145,045	126,131	95,194
Real estate expenses										58,115	49,135	37,235
Net operating income										86,930	76,996	57,959
Capital expenditures										24,675	25,779	25,117
Total assets	1,333,235	1,333,235				1,340,634				1,333,235	1,340,634	792,170
Corporate and other
Segment Reconciliation [Abstract]
Real estate rental revenue										16,746	18,990	18,062
Real estate expenses										5,342	5,522	5,036
Net operating income										11,404	13,468	13,026
Capital expenditures										2,494	4,534	4,897
Total assets	$ 136,514	$ 136,514				$ 153,547				$ 136,514	$ 153,547	$ 376,261

Selected Quarterly Financial _3

Selected Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Real estate rental revenue	$ 71,229	$ 73,227	$ 72,870	$ 76,792	$ 80,667	$ 80,259	$ 76,820	$ 71,434	$ 294,118	$ 309,180	$ 291,730
Income (loss) from continuing operations	(11,037)	(956)	(5,406)	1,719	54,198	(8,432)	(6,191)	(10,443)	(15,680)	29,132	1,153
Net income (loss)	$ (11,037)	$ (956)	$ (5,406)	$ 1,719	$ 54,198	$ 332,770	$ 987	$ (4,405)	$ (15,680)	$ 383,550	$ 25,630
Income (loss) from continuing operations - Basic (in dollars per share)	$ (0.13)	$ (0.01)	$ (0.07)	$ 0.02	$ 0.66	$ (0.10)	$ (0.08)	$ (0.13)	$ (0.20)	$ 0.36	$ 0.01
Income (loss) from continuing operations - Diluted (in dollars per share)	(0.13)	(0.01)	(0.07)	0.02	0.66	(0.10)	(0.08)	(0.13)	(0.20)	0.36	0.01
Net income (loss) per share - Basic (in dollars per share)	(0.13)	(0.01)	(0.07)	0.02	0.66	4.14	0.01	(0.06)	(0.20)	4.75	0.32
Net income (loss) per share - Diluted (in dollars per share)	$ (0.13)	$ (0.01)	$ (0.07)	$ 0.02	$ 0.66	$ 4.14	$ 0.01	$ (0.06)	$ (0.20)	$ 4.75	$ 0.32
(Loss) gain on sale of real estate	$ (7,500)		$ (7,500)		$ 61,000		$ (1,000)		$ (15,009)	$ 59,961	$ 2,495
Gain on sale of real estate						$ 339,000			$ 0	$ 339,024	$ 0

Shareholders' Equity - Narrativ

Shareholders' Equity - Narrative (Details)	May 04, 2018USD ($)agreement
Equity [Abstract]
Number of equity distribution agreements | agreement	8
Common shares reserved for future issuance | $	$ 250,000,000

Shareholders' Equity - Issuance

Shareholders' Equity - Issuances and Net Proceeds on Equity Distribution Agreements (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Equity [Abstract]
Issuance of common shares (in shares)	2,000	1,859	1,165
Weighted average price per share	$ 23.86	$ 30	$ 31.18
Net proceeds	$ 48,355	$ 54,916	$ 35,472

Shareholders' Equity - Dividend

Shareholders' Equity - Dividend Reinvestment Program (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Dividend Reinvestment Program
Issuance of common shares (in shares)	89	173	81
Weighted average price per share	$ 24.12	$ 27.58	$ 29.18
Net proceeds	$ 2,121	$ 4,755	$ 1,973

Deferred Costs - Deferred Lease

Deferred Costs - Deferred Lease Costs and Incentives in Prepaid Expenses and Other Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Deferred leasing costs, gross	$ 55,736	$ 60,900
Deferred leasing costs, accumulated amortization	30,700	29,580
Deferred leasing costs, net	25,036	31,320
Deferred leasing incentives, gross	22,942	18,926
Deferred leasing incentives, accumulated amortization	18,076	11,133
Deferred leasing incentives, net	$ 4,866	$ 7,793

Deferred Costs - Amortization a

Deferred Costs - Amortization and Write-Offs of Deferred Leasing Costs and Incentives (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Deferred leasing costs amortization	$ 5,389	$ 6,599	$ 5,881
Deferred leasing incentives amortization	$ 2,070	$ 2,862	$ 2,811

Schedule II Valuation and Qua_2

Schedule II Valuation and Qualifying Accounts (Details) - Valuation allowance for deferred tax assets - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	$ 1,402	$ 1,419	$ 1,413
Additions Charged to Expenses	0	0	6
Net Recoveries	0	(17)	0
Balance at End of Year	$ 1,402	$ 1,402	$ 1,419

Schedule III Real Estate and _2

Schedule III Real Estate and Accumulated Depreciation - By Property (Details) ft² in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)ft²unit	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Initial Cost
Land	$ 566,013
Buildings and Improvements	1,569,915
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	885,304
Gross Amounts at Which Carried
Land	551,578
Buildings and Improvements	2,469,654
Total	3,021,232	$ 3,159,463	$ 2,973,816	$ 2,831,683
Accumulated Depreciation	$ 749,014	712,630	$ 770,535	$ 690,417
Net Rentable Square Feet (sq ft) | ft²	9,461
Units | unit	7,059
Carrying value for federal income tax purposes	$ 1,920,000
Investment in development of property	$ 37,615	124,193
Building and improvements | Minimum
Gross Amounts at Which Carried
Useful life (in years)	3 years
Building and improvements | Maximum
Gross Amounts at Which Carried
Useful life (in years)	50 years
Various development projects
Gross Amounts at Which Carried
Investment in development of property	$ 1,900
Multifamily Properties
Initial Cost
Land	269,521
Buildings and Improvements	897,579
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	475,478
Gross Amounts at Which Carried
Land	255,957
Buildings and Improvements	1,386,621
Total	1,642,578
Accumulated Depreciation	$ 315,725
Net Rentable Square Feet (sq ft) | ft²	6,097
Units | unit	7,059
Investment in development of property	$ 36,493	123,071
Multifamily Properties | 3801 Connecticut Avenue | Washington, D.C.
Initial Cost
Land	420
Buildings and Improvements	2,678
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	20,399
Gross Amounts at Which Carried
Land	420
Buildings and Improvements	23,077
Total	23,497
Accumulated Depreciation	$ 14,646
Net Rentable Square Feet (sq ft) | ft²	178
Units | unit	307
Depreciation Life	30 years
Multifamily Properties | Roosevelt Towers | Virginia
Initial Cost
Land	$ 336
Buildings and Improvements	1,996
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	13,915
Gross Amounts at Which Carried
Land	336
Buildings and Improvements	15,911
Total	16,247
Accumulated Depreciation	$ 12,104
Net Rentable Square Feet (sq ft) | ft²	170
Units | unit	191
Depreciation Life	40 years
Multifamily Properties | Park Adams | Virginia
Initial Cost
Land	$ 287
Buildings and Improvements	1,654
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	14,053
Gross Amounts at Which Carried
Land	287
Buildings and Improvements	15,707
Total	15,994
Accumulated Depreciation	$ 11,776
Net Rentable Square Feet (sq ft) | ft²	173
Units | unit	200
Depreciation Life	35 years
Multifamily Properties | The Ashby at McLean | Virginia
Initial Cost
Land	$ 4,356
Buildings and Improvements	17,102
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	28,435
Gross Amounts at Which Carried
Land	4,356
Buildings and Improvements	45,537
Total	49,893
Accumulated Depreciation	$ 30,928
Net Rentable Square Feet (sq ft) | ft²	274
Units | unit	256
Depreciation Life	30 years
Multifamily Properties | Bethesda Hill Apartments | Maryland
Initial Cost
Land	$ 3,900
Buildings and Improvements	13,412
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	16,664
Gross Amounts at Which Carried
Land	3,900
Buildings and Improvements	30,076
Total	33,976
Accumulated Depreciation	$ 22,059
Net Rentable Square Feet (sq ft) | ft²	225
Units | unit	195
Depreciation Life	30 years
Multifamily Properties | Bennett Park | Virginia
Initial Cost
Land	$ 2,861
Buildings and Improvements	917
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	82,514
Gross Amounts at Which Carried
Land	4,774
Buildings and Improvements	81,518
Total	86,292
Accumulated Depreciation	$ 43,271
Net Rentable Square Feet (sq ft) | ft²	215
Units | unit	224
Depreciation Life	28 years
Multifamily Properties | The Clayborne | Virginia
Initial Cost
Land	$ 269
Buildings and Improvements	0
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	31,574
Gross Amounts at Which Carried
Land	699
Buildings and Improvements	31,144
Total	31,843
Accumulated Depreciation	$ 17,936
Net Rentable Square Feet (sq ft) | ft²	60
Units | unit	74
Depreciation Life	26 years
Multifamily Properties | The Kenmore | Washington, D.C.
Initial Cost
Land	$ 28,222
Buildings and Improvements	33,955
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	19,618
Gross Amounts at Which Carried
Land	28,222
Buildings and Improvements	53,573
Total	81,795
Accumulated Depreciation	$ 19,891
Net Rentable Square Feet (sq ft) | ft²	268
Units | unit	374
Depreciation Life	30 years
Multifamily Properties | The Maxwell | Virginia
Initial Cost
Land	$ 12,787
Buildings and Improvements	0
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	38,240
Gross Amounts at Which Carried
Land	12,848
Buildings and Improvements	38,179
Total	51,027
Accumulated Depreciation	$ 12,541
Net Rentable Square Feet (sq ft) | ft²	116
Units | unit	163
Depreciation Life	30 years
Multifamily Properties | Yale West | Washington, D.C.
Initial Cost
Land	$ 14,684
Buildings and Improvements	62,069
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	1,775
Gross Amounts at Which Carried
Land	14,684
Buildings and Improvements	63,844
Total	78,528
Accumulated Depreciation	$ 15,728
Net Rentable Square Feet (sq ft) | ft²	141
Units | unit	135
Depreciation Life	30 years
Multifamily Properties | The Paramount | Virginia
Initial Cost
Land	$ 8,568
Buildings and Improvements	38,716
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	3,512
Gross Amounts at Which Carried
Land	8,568
Buildings and Improvements	42,228
Total	50,796
Accumulated Depreciation	$ 12,922
Net Rentable Square Feet (sq ft) | ft²	173
Units | unit	216
Depreciation Life	30 years
Multifamily Properties | The Wellington | Virginia
Initial Cost
Land	$ 30,548
Buildings and Improvements	116,563
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	17,815
Gross Amounts at Which Carried
Land	30,548
Buildings and Improvements	134,378
Total	164,926
Accumulated Depreciation	$ 27,667
Net Rentable Square Feet (sq ft) | ft²	600
Units | unit	711
Depreciation Life	30 years
Multifamily Properties | The Trove | Virginia
Initial Cost
Land	$ 15,000
Buildings and Improvements	0
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	117,215
Gross Amounts at Which Carried
Land	15,000
Buildings and Improvements	117,215
Total	132,215
Accumulated Depreciation	$ 3,261
Net Rentable Square Feet (sq ft) | ft²	293
Units | unit	401
Depreciation Life	30 years
Investment in development of property	$ 7,100
Multifamily Properties | Riverside Apartments | Virginia
Initial Cost
Land	38,924
Buildings and Improvements	184,854
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	40,324
Gross Amounts at Which Carried
Land	38,924
Buildings and Improvements	225,178
Total	264,102
Accumulated Depreciation	$ 40,760
Net Rentable Square Feet (sq ft) | ft²	1,001
Units | unit	1,222
Depreciation Life	30 years
Multifamily Properties | Riverside Apartments land parcel | Virginia
Initial Cost
Land	$ 15,968
Buildings and Improvements	0
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	12,658
Gross Amounts at Which Carried
Land	0
Buildings and Improvements	28,626
Total	28,626
Accumulated Depreciation	$ 0
Net Rentable Square Feet (sq ft) | ft²	0
Investment in development of property	$ 28,600
Multifamily Properties | Assembly Alexandria | Virginia
Initial Cost
Land	23,942
Buildings and Improvements	93,672
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	5,501
Gross Amounts at Which Carried
Land	23,942
Buildings and Improvements	99,173
Total	123,115
Accumulated Depreciation	$ 6,474
Net Rentable Square Feet (sq ft) | ft²	437
Units | unit	532
Depreciation Life	30 years
Multifamily Properties | Assembly Manassas | Virginia
Initial Cost
Land	$ 13,586
Buildings and Improvements	68,802
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	1,741
Gross Amounts at Which Carried
Land	13,586
Buildings and Improvements	70,543
Total	84,129
Accumulated Depreciation	$ 4,975
Net Rentable Square Feet (sq ft) | ft²	390
Units | unit	408
Depreciation Life	30 years
Multifamily Properties | Assembly Dulles | Virginia
Initial Cost
Land	$ 12,476
Buildings and Improvements	66,852
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	1,964
Gross Amounts at Which Carried
Land	12,476
Buildings and Improvements	68,816
Total	81,292
Accumulated Depreciation	$ 4,723
Net Rentable Square Feet (sq ft) | ft²	361
Units | unit	328
Depreciation Life	30 years
Multifamily Properties | Assembly Leesburg | Virginia
Initial Cost
Land	$ 4,113
Buildings and Improvements	21,286
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	387
Gross Amounts at Which Carried
Land	4,113
Buildings and Improvements	21,673
Total	25,786
Accumulated Depreciation	$ 1,679
Net Rentable Square Feet (sq ft) | ft²	124
Units | unit	134
Depreciation Life	30 years
Multifamily Properties | Assembly Herndon | Virginia
Initial Cost
Land	$ 11,225
Buildings and Improvements	51,534
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	4,023
Gross Amounts at Which Carried
Land	11,225
Buildings and Improvements	55,557
Total	66,782
Accumulated Depreciation	$ 3,984
Net Rentable Square Feet (sq ft) | ft²	221
Units | unit	283
Depreciation Life	30 years
Multifamily Properties | Assembly Germantown | Maryland
Initial Cost
Land	$ 7,609
Buildings and Improvements	34,431
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	1,193
Gross Amounts at Which Carried
Land	7,609
Buildings and Improvements	35,624
Total	43,233
Accumulated Depreciation	$ 2,566
Net Rentable Square Feet (sq ft) | ft²	211
Units | unit	218
Depreciation Life	30 years
Multifamily Properties | Assembly Watkins Mill | Maryland
Initial Cost
Land	$ 7,151
Buildings and Improvements	30,851
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	636
Gross Amounts at Which Carried
Land	7,151
Buildings and Improvements	31,487
Total	38,638
Accumulated Depreciation	$ 2,207
Net Rentable Square Feet (sq ft) | ft²	193
Units | unit	210
Depreciation Life	30 years
Multifamily Properties | Cascade at Landmark | Virginia
Initial Cost
Land	$ 12,289
Buildings and Improvements	56,235
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	1,322
Gross Amounts at Which Carried
Land	12,289
Buildings and Improvements	57,557
Total	69,846
Accumulated Depreciation	$ 3,627
Net Rentable Square Feet (sq ft) | ft²	273
Units | unit	277
Depreciation Life	30 years
Office Buildings
Initial Cost
Land	$ 263,316
Buildings and Improvements	591,161
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	360,482
Gross Amounts at Which Carried
Land	263,086
Buildings and Improvements	951,873
Total	1,214,959
Accumulated Depreciation	$ 374,540
Net Rentable Square Feet (sq ft) | ft²	2,665
Investment in development of property	$ 478	$ 478
Office Buildings | 1901 Pennsylvania Avenue | Washington, D.C.
Initial Cost
Land	892
Buildings and Improvements	3,481
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	21,602
Gross Amounts at Which Carried
Land	892
Buildings and Improvements	25,083
Total	25,975
Accumulated Depreciation	$ 19,521
Net Rentable Square Feet (sq ft) | ft²	101
Depreciation Life	28 years
Office Buildings | 515 King Street | Virginia
Initial Cost
Land	$ 4,102
Buildings and Improvements	3,931
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	9,319
Gross Amounts at Which Carried
Land	4,102
Buildings and Improvements	13,250
Total	17,352
Accumulated Depreciation	$ 7,709
Net Rentable Square Feet (sq ft) | ft²	75
Depreciation Life	50 years
Office Buildings | 1220 19th Street | Washington, D.C.
Initial Cost
Land	$ 7,803
Buildings and Improvements	11,366
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	18,609
Gross Amounts at Which Carried
Land	7,803
Buildings and Improvements	29,975
Total	37,778
Accumulated Depreciation	$ 20,087
Net Rentable Square Feet (sq ft) | ft²	103
Depreciation Life	30 years
Office Buildings | 1600 Wilson Boulevard | Virginia
Initial Cost
Land	$ 6,661
Buildings and Improvements	16,742
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	31,803
Gross Amounts at Which Carried
Land	6,661
Buildings and Improvements	48,545
Total	55,206
Accumulated Depreciation	$ 31,854
Net Rentable Square Feet (sq ft) | ft²	171
Depreciation Life	30 years
Office Buildings | Silverline Center | Virginia
Initial Cost
Land	$ 12,049
Buildings and Improvements	71,825
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	104,041
Gross Amounts at Which Carried
Land	12,049
Buildings and Improvements	175,866
Total	187,915
Accumulated Depreciation	$ 112,929
Net Rentable Square Feet (sq ft) | ft²	552
Depreciation Life	30 years
Office Buildings | Courthouse Square | Virginia
Initial Cost
Land	$ 0
Buildings and Improvements	17,096
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	10,248
Gross Amounts at Which Carried
Land	0
Buildings and Improvements	27,344
Total	27,344
Accumulated Depreciation	$ 18,712
Net Rentable Square Feet (sq ft) | ft²	121
Depreciation Life	30 years
Office Buildings | 2000 M Street | Washington, D.C.
Initial Cost
Land	$ 0
Buildings and Improvements	61,101
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	42,983
Gross Amounts at Which Carried
Land	0
Buildings and Improvements	104,084
Total	104,084
Accumulated Depreciation	$ 44,470
Net Rentable Square Feet (sq ft) | ft²	233
Depreciation Life	30 years
Office Buildings | 1140 Connecticut Avenue | Washington, D.C.
Initial Cost
Land	$ 25,226
Buildings and Improvements	50,495
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	19,800
Gross Amounts at Which Carried
Land	25,226
Buildings and Improvements	70,295
Total	95,521
Accumulated Depreciation	$ 27,200
Net Rentable Square Feet (sq ft) | ft²	184
Depreciation Life	30 years
Office Buildings | Fairgate at Ballston | Virginia
Initial Cost
Land	$ 17,750
Buildings and Improvements	29,885
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	8,289
Gross Amounts at Which Carried
Land	17,750
Buildings and Improvements	38,174
Total	55,924
Accumulated Depreciation	$ 14,375
Net Rentable Square Feet (sq ft) | ft²	144
Depreciation Life	30 years
Office Buildings | Army Navy Building | Washington, D.C.
Initial Cost
Land	$ 30,796
Buildings and Improvements	39,315
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	13,116
Gross Amounts at Which Carried
Land	30,796
Buildings and Improvements	52,431
Total	83,227
Accumulated Depreciation	$ 15,831
Net Rentable Square Feet (sq ft) | ft²	108
Depreciation Life	30 years
Office Buildings | 1775 Eye Street, NW | Washington, D.C.
Initial Cost
Land	$ 48,086
Buildings and Improvements	51,074
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	20,742
Gross Amounts at Which Carried
Land	48,086
Buildings and Improvements	71,816
Total	119,902
Accumulated Depreciation	$ 20,606
Net Rentable Square Feet (sq ft) | ft²	189
Depreciation Life	30 years
Office Buildings | Watergate 600 | Washington, D.C.
Initial Cost
Land	$ 45,981
Buildings and Improvements	78,325
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	43,902
Gross Amounts at Which Carried
Land	45,751
Buildings and Improvements	122,457
Total	168,208
Accumulated Depreciation	$ 19,068
Net Rentable Square Feet (sq ft) | ft²	294
Depreciation Life	30 years
Office Buildings | Arlington Tower | Virginia
Initial Cost
Land	$ 63,970
Buildings and Improvements	156,525
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	16,028
Gross Amounts at Which Carried
Land	63,970
Buildings and Improvements	172,553
Total	236,523
Accumulated Depreciation	$ 22,178
Net Rentable Square Feet (sq ft) | ft²	390
Depreciation Life	30 years
Retail Centers
Initial Cost
Land	$ 33,176
Buildings and Improvements	81,175
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	49,344
Gross Amounts at Which Carried
Land	32,535
Buildings and Improvements	131,160
Total	163,695
Accumulated Depreciation	$ 58,749
Net Rentable Square Feet (sq ft) | ft²	699
Retail Centers | Westminster | Maryland
Initial Cost
Land	$ 519
Buildings and Improvements	1,775
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	10,022
Gross Amounts at Which Carried
Land	519
Buildings and Improvements	11,797
Total	12,316
Accumulated Depreciation	$ 8,938
Net Rentable Square Feet (sq ft) | ft²	150
Depreciation Life	37 years
Retail Centers | Concord Centre | Virginia
Initial Cost
Land	$ 413
Buildings and Improvements	850
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	7,628
Gross Amounts at Which Carried
Land	413
Buildings and Improvements	8,478
Total	8,891
Accumulated Depreciation	$ 4,353
Net Rentable Square Feet (sq ft) | ft²	75
Depreciation Life	33 years
Retail Centers | Takoma Park | Maryland
Initial Cost
Land	$ 415
Buildings and Improvements	1,084
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	302
Gross Amounts at Which Carried
Land	366
Buildings and Improvements	1,435
Total	1,801
Accumulated Depreciation	$ 1,210
Net Rentable Square Feet (sq ft) | ft²	51
Depreciation Life	50 years
Retail Centers | Chevy Chase Metro Plaza | Washington, D.C.
Initial Cost
Land	$ 1,549
Buildings and Improvements	4,304
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	8,438
Gross Amounts at Which Carried
Land	1,549
Buildings and Improvements	12,742
Total	14,291
Accumulated Depreciation	$ 8,743
Net Rentable Square Feet (sq ft) | ft²	49
Depreciation Life	50 years
Retail Centers | 800 S. Washington Street | Virginia
Initial Cost
Land	$ 2,904
Buildings and Improvements	5,489
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	6,154
Gross Amounts at Which Carried
Land	2,904
Buildings and Improvements	11,643
Total	14,547
Accumulated Depreciation	$ 6,562
Net Rentable Square Feet (sq ft) | ft²	46
Depreciation Life	30 years
Retail Centers | Randolph Shopping Center | Maryland
Initial Cost
Land	$ 4,928
Buildings and Improvements	13,025
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	1,436
Gross Amounts at Which Carried
Land	4,928
Buildings and Improvements	14,461
Total	19,389
Accumulated Depreciation	$ 7,369
Net Rentable Square Feet (sq ft) | ft²	83
Depreciation Life	30 years
Retail Centers | Montrose Shopping Center | Maryland
Initial Cost
Land	$ 11,612
Buildings and Improvements	22,410
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	2,604
Gross Amounts at Which Carried
Land	11,020
Buildings and Improvements	25,606
Total	36,626
Accumulated Depreciation	$ 12,723
Net Rentable Square Feet (sq ft) | ft²	151
Depreciation Life	30 years
Retail Centers | Spring Valley Village | Washington, D.C.
Initial Cost
Land	$ 10,836
Buildings and Improvements	32,238
Net Improvements (Retirement) since Acquisition
Net Improvements (Retirement) since Acquisition	12,760
Gross Amounts at Which Carried
Land	10,836
Buildings and Improvements	44,998
Total	55,834
Accumulated Depreciation	$ 8,851
Net Rentable Square Feet (sq ft) | ft²	94
Depreciation Life	30 years

Schedule III Real Estate and _3

Schedule III Real Estate and Accumulated Depreciation - Reconciliation of Real Estate Assets and Accumulated Depreciation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Real estate assets
Balance, beginning of period	$ 3,159,463	$ 2,973,816	$ 2,831,683
Property acquisitions	0	516,054	220,495
Improvements	81,119	140,109	103,404
Impairment write-down	0	(24,432)	(2,177)
Write-off of disposed assets	(1,694)	(7,430)	(2,132)
Property sales	(217,656)	(438,654)	(177,457)
Balance, end of period	3,021,232	3,159,463	2,973,816
Accumulated depreciation
Balance, beginning of period	712,630	770,535	690,417
Depreciation	106,920	107,938	98,141
Impairment write-down	0	(16,058)	(291)
Write-off of disposed assets	(730)	(2,173)	(1,859)
Property sales	(69,806)	(147,612)	(15,873)
Balance, end of period	$ 749,014	$ 712,630	$ 770,535