JBG SMITH Properties (JBGS) 10-Q 3 Nov 20 2020 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2020	Oct. 30, 2020
Cover page.
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2020
Document Transition Report	false
Entity File Number	001-37994
Entity Registrant Name	JBG SMITH PROPERTIES
Entity Incorporation, State or Country Code	MD
Entity Tax Identification Number	81-4307010
Entity Address, Address Line One	4747 Bethesda Avenue
Entity Address, City or Town	Bethesda
Entity Address, State or Province	MD
Entity Address, Postal Zip Code	20814
Entity Address, Address Line Two	Suite 200
City Area Code	240
Local Phone Number	333-3600
Title of 12(b) Security	Common Shares, par value $0.01 per share
Trading Symbol	JBGS
Security Exchange Name	NYSE
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
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		132,464,702
Entity Central Index Key	0001689796
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Amendment Flag	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Real estate, at cost:
Land and improvements	$ 1,314,106	$ 1,240,455
Buildings and improvements	4,225,616	3,880,973
Construction in progress, including land	400,933	654,091
Real estate, at cost	5,940,655	5,775,519
Less accumulated depreciation	(1,227,027)	(1,119,571)
Real estate, net	4,713,628	4,655,948
Cash and cash equivalents	455,111	126,413
Restricted cash	37,602	16,103
Tenant and other receivables, net	47,460	52,941
Deferred rent receivable	184,394	169,721
Investments in unconsolidated real estate ventures	463,026	543,026
Other assets, net	302,014	253,687
Assets held for sale	74,089	168,412
TOTAL ASSETS	6,277,324	5,986,251
Liabilities:
Mortgages payable, net	1,690,723	1,125,777
Revolving credit facility		200,000
Unsecured term loans, net	397,808	297,295
Accounts payable and accrued expenses	111,440	157,702
Other liabilities, net	216,494	206,042
Total liabilities	2,416,465	1,986,816
Commitments and contingencies
Redeemable noncontrolling interests	490,921	612,758
Shareholders' equity:
Preferred shares, $0.01 par value - 200,000 shares authorized, none issued	0	0
Common shares, $0.01 par value - 500,000 shares authorized; 132,438 and 134,148 shares issued and outstanding as of September 30, 2020 and December 31, 2019	1,325	1,342
Additional paid-in capital	3,721,059	3,633,042
Accumulated deficit	(307,975)	(231,164)
Accumulated other comprehensive loss	(44,650)	(16,744)
Total shareholders' equity of JBG SMITH Properties	3,369,759	3,386,476
Noncontrolling interests in consolidated subsidiaries	179	201
Total equity	3,369,938	3,386,677
TOTAL LIABILITIES, REDEEMABLE NONCONTROLLING INTERESTS AND EQUITY	$ 6,277,324	$ 5,986,251

Condensed Consolidated and Comb

Condensed Consolidated and Combined Balance Sheets (Parenthetical) - $ / shares shares in Thousands	Sep. 30, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Preferred shares, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred shares, shares authorized	200,000	200,000
Preferred shares, shares issued	0	0
Common shares, par value (in dollars per share)	$ 0.01	$ 0.01
Common shares, shares authorized	500,000	500,000
Common shares, shares issued	132,438	134,148
Common shares, shares outstanding	132,438	134,148

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
REVENUE
Property rental	$ 118,680	$ 123,963	$ 354,519	$ 365,702
Third-party real estate services, including reimbursements	26,987	34,587	83,870	91,765
Other revenue	5,368	8,527	15,705	25,426
Total revenue	151,035	167,077	454,094	482,893
EXPENSES
Depreciation and amortization	56,481	46,862	157,586	141,576
Property operating	37,572	35,800	105,867	100,087
Real estate taxes	17,354	16,740	53,422	52,241
General and administrative:
Corporate and other	11,086	11,015	37,478	34,888
Third-party real estate services	28,207	29,809	86,260	86,585
Share-based compensation related to Formation Transaction and special equity awards	7,133	9,549	25,432	30,203
Transaction and other costs	845	2,059	7,526	9,928
Total expenses	158,678	151,834	473,571	455,508
OTHER INCOME (EXPENSE)
Income (loss) from unconsolidated real estate ventures, net	(965)	(1,144)	(17,142)	647
Interest and other income (loss), net		(640)	1,021	2,363
Interest expense	(16,885)	(10,583)	(44,660)	(40,864)
Gain on sale of real estate		8,088	59,477	47,121
Loss on extinguishment of debt			(33)	(1,889)
Total other income (expense)	(17,850)	(4,279)	(1,337)	7,378
INCOME (LOSS) BEFORE INCOME TAX (EXPENSE) BENEFIT	(25,493)	10,964	(20,814)	34,763
Income tax (expense) benefit	488	(432)	3,721	689
NET INCOME (LOSS)	(25,005)	10,532	(17,093)	35,452
Net (income) loss attributable to redeemable noncontrolling interests	2,212	(1,172)	445	(4,271)
NET INCOME (LOSS) ATTRIBUTABLE TO COMMON SHAREHOLDERS	$ (22,793)	$ 9,360	$ (16,648)	$ 31,181
EARNINGS (LOSS) PER COMMON SHARE:
Earnings, (loss) Per Share, Basic	$ (0.18)	$ 0.06	$ (0.14)	$ 0.23
Earnings, (loss) Per Share, Diluted	$ (0.18)	$ 0.06	$ (0.14)	$ 0.23
Weighted average number of common shares outstanding - basic	133,620	134,127	133,924	129,527
Weighted average number of common shares outstanding - diluted	133,620	134,127	133,924	129,527

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Loss [Abstract]
Net income (loss)	$ (25,005)	$ 10,532	$ (17,093)	$ 35,452
OTHER COMPREHENSIVE INCOME (LOSS):
Change in fair value of derivative financial instruments	(278)	(7,014)	(39,489)	(33,966)
Reclassification of net (income) loss on derivative financial instruments from accumulated other comprehensive loss into interest expense	3,823	(211)	8,137	(2,001)
Other comprehensive income (loss)	3,545	(7,225)	(31,352)	(35,967)
COMPREHENSIVE INCOME (LOSS)	(21,460)	3,307	(48,445)	(515)
Net (income) loss attributable to redeemable noncontrolling interests	2,212	(1,172)	445	(4,271)
Other comprehensive (income) loss attributable to redeemable noncontrolling interests	(309)	803	3,446	3,689
COMPREHENSIVE INCOME (LOSS) ATTRIBUTABLE TO JBG SMITH PROPERTIES	$ (19,557)	$ 2,938	$ (44,554)	$ (1,097)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Equity - USD ($) shares in Thousands, $ in Thousands	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Loss	Noncontrolling Interests in Consolidated Subsidiaries	Total
Balance at beginning of period at Dec. 31, 2018	$ 1,210	$ 3,155,256	$ (176,018)	$ 6,700	$ 204	$ 2,987,352
Balance at beginning of period (in shares) at Dec. 31, 2018	120,937
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss) attributable to common shareholders and noncontrolling interests			31,181			31,181
Common shares issued	$ 115	472,665				472,780
Common shares issued (in shares)	11,500
Conversion of common limited partnership units to common shares	$ 17	57,301				57,318
Conversion of common limited partnership units to common shares (in shares)	1,664
Common shares issued pursuant to Employee Share Purchase Plan		1,018				1,018
Common shares issued pursuant to Employee Share Purchase Plan ( in shares)	26
Dividends declared on common shares			(60,355)			(60,355)
Contributions from (distributions to) noncontrolling interests					126	126
Redeemable noncontrolling interests redemption value adjustment and other comprehensive (loss) income allocation		(42,907)		3,689		(39,218)
Other comprehensive loss				(35,967)		(35,967)
Balance at end of period (in shares) at Sep. 30, 2019	134,127
Balance at end of period at Sep. 30, 2019	$ 1,342	3,643,333	(205,192)	(25,578)	330	3,414,235
Balance at beginning of period at Jun. 30, 2019	$ 1,342	3,644,699	(184,373)	(19,156)	346	3,442,858
Balance at beginning of period (in shares) at Jun. 30, 2019	134,127
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss) attributable to common shareholders and noncontrolling interests			9,360			9,360
Common shares issued pursuant to Employee Share Purchase Plan		80				80
Dividends declared on common shares			(30,179)			(30,179)
Contributions from (distributions to) noncontrolling interests					(16)	(16)
Redeemable noncontrolling interests redemption value adjustment and other comprehensive (loss) income allocation		(1,446)		803		(643)
Other comprehensive loss				(7,225)		(7,225)
Balance at end of period (in shares) at Sep. 30, 2019	134,127
Balance at end of period at Sep. 30, 2019	$ 1,342	3,643,333	(205,192)	(25,578)	330	3,414,235
Balance at beginning of period at Dec. 31, 2019	$ 1,342	3,633,042	(231,164)	(16,744)	201	$ 3,386,677
Balance at beginning of period (in shares) at Dec. 31, 2019	134,148					134,148
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss) attributable to common shareholders and noncontrolling interests			(16,648)			$ (16,648)
Conversion of common limited partnership units to common shares	$ 12	40,662				40,674
Conversion of common limited partnership units to common shares (in shares)	1,112
Common shares repurchased	$ (29)	(79,540)				(79,569)
Common shares repurchased (in shares)	(2,857)
Common shares issued pursuant to Employee Share Purchase Plan		1,320				1,320
Common shares issued pursuant to Employee Share Purchase Plan ( in shares)	35
Dividends declared on common shares			(60,163)			(60,163)
Contributions from (distributions to) noncontrolling interests					(22)	(22)
Redeemable noncontrolling interests redemption value adjustment and other comprehensive (loss) income allocation		125,575		3,446		129,021
Other comprehensive loss				(31,352)		$ (31,352)
Balance at end of period (in shares) at Sep. 30, 2020	132,438					132,438
Balance at end of period at Sep. 30, 2020	$ 1,325	3,721,059	(307,975)	(44,650)	179	$ 3,369,938
Balance at beginning of period at Jun. 30, 2020	$ 1,338	3,742,205	(255,162)	(47,886)	191	3,440,686
Balance at beginning of period (in shares) at Jun. 30, 2020	133,708
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss) attributable to common shareholders and noncontrolling interests			(22,793)			(22,793)
Conversion of common limited partnership units to common shares	$ 2	4,794				4,796
Conversion of common limited partnership units to common shares (in shares)	169
Common shares repurchased	$ (15)	(38,362)				(38,377)
Common shares repurchased (in shares)	(1,439)
Common shares issued pursuant to Employee Share Purchase Plan		186				186
Dividends declared on common shares			(30,020)			(30,020)
Contributions from (distributions to) noncontrolling interests					(12)	(12)
Redeemable noncontrolling interests redemption value adjustment and other comprehensive (loss) income allocation		12,236		(309)		11,927
Other comprehensive loss				3,545		$ 3,545
Balance at end of period (in shares) at Sep. 30, 2020	132,438					132,438
Balance at end of period at Sep. 30, 2020	$ 1,325	$ 3,721,059	$ (307,975)	$ (44,650)	$ 179	$ 3,369,938

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Equity (Parenthetical) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Stockholders' Equity [Abstract]
Common Stock, Dividends, Per Share, Declared	$ 0.225	$ 0.225	$ 0.45	$ 0.45

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
OPERATING ACTIVITIES:
Net income (loss)	$ (17,093)	$ 35,452
Adjustments to reconcile net income to net cash provided by operating activities:
Share-based compensation expense	53,183	47,432
Depreciation and amortization, including amortization of debt issuance costs	160,395	144,868
Deferred rent	(19,124)	(29,164)
(Income) loss from unconsolidated real estate ventures, net	17,142	(647)
Amortization of market lease intangibles, net	(356)	(486)
Amortization of lease incentives	5,144	4,344
Loss on extinguishment of debt	33	1,889
Gain on sale of real estate	(59,477)	(47,121)
Net unrealized loss on ineffective derivative financial instruments	173	50
Losses on operating lease and other receivables	14,750	1,281
Return on capital from unconsolidated real estate ventures	3,697	1,836
Other non-cash items	265	70
Changes in operating assets and liabilities:
Tenant and other receivables	(4,757)	(9,077)
Other assets, net	(11,566)	(13,858)
Accounts payable and accrued expenses	1,366	(17,171)
Other liabilities, net	(15,747)	(7,009)
Net cash provided by operating activities	127,855	112,639
INVESTING ACTIVITIES:
Development costs, construction in progress and real estate additions	(245,456)	(294,355)
Deposits for real estate and other acquisitions	(25,274)	(9,125)
Proceeds from sale of real estate	154,493	157,810
Distributions of capital from unconsolidated real estate ventures	70,818	7,557
Investments in unconsolidated real estate ventures	(12,277)	(7,325)
Net cash used in investing activities	(57,696)	(145,438)
FINANCING ACTIVITIES:
Finance lease payments	(3,281)	(103)
Borrowings under mortgages payable	580,105
Borrowings under revolving credit facility	500,000
Borrowings under unsecured term loans	100,000
Repayments of mortgages payable	(6,680)	(482,810)
Repayments of revolving credit facility	(700,000)
Debt issuance costs	(14,856)	(515)
Proceeds from the issuance of common stock, net of issuance costs		472,780
Proceeds from common stock issued pursuant to ESPP	887	747
Common shares repurchased	(74,434)
Dividends paid to common shareholders	(90,347)	(99,654)
Distributions to redeemable noncontrolling interests	(11,333)	(13,564)
Distributions to noncontrolling interests	(23)	(19)
Contributions from noncontrolling interests		125
Net cash provided by (used in) financing activities	280,038	(123,013)
Net increase (decrease) in cash and cash equivalents and restricted cash	350,197	(155,812)
Cash and cash equivalents and restricted cash as of the beginning of the period	142,516	399,532
Cash and cash equivalents and restricted cash as of the end of the period	492,713	243,720
SUPPLEMENTAL DISCLOSURE OF CASH FLOW AND NON-CASH INFORMATION:
Cash paid for interest (net of capitalized interest of $11,545 and $23,211 in 2020 and 2019)	40,744	38,563
Accrued capital expenditures included in accounts payable and accrued expenses	51,092	99,876
Write-off of fully depreciated assets	29,393	49,319
Conversion of common limited partnership units to common shares	40,674	57,318
Recognition (derecognition) of operating lease right-of-use assets	(13,151)	35,318
Recognition (derecognition) of liabilities related to operating lease right-of-use assets	(13,151)	37,922
Recognition of finance lease right-of-use assets	42,354
Recognition of liabilities related to finance lease right-of-use assets	40,684
Cash paid for amounts included in the measurement of lease liabilities for operating leases	$ 4,603	$ 4,629

Condensed Consolidated Statem_6

Condensed Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
CASH AND CASH EQUIVALENTS AND RESTRICTED CASH AS OF END OF THE PERIOD:
Cash and cash equivalents	$ 455,111	$ 230,147	$ 455,111	$ 230,147	$ 126,413
Restricted cash	37,602	13,573	37,602	13,573	16,103
Cash and cash equivalents and restricted cash	492,713	243,720	492,713	243,720	$ 142,516	$ 399,532
Capitalized interest	$ 2,912	$ 8,258	$ 11,545	$ 23,211

Organization and Basis of Prese

Organization and Basis of Presentation	9 Months Ended
	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Basis of Presentation	1. Organization JBG SMITH Properties ("JBG SMITH") is a Maryland real estate investment trust ("REIT"), which owns and operates a portfolio of high-growth commercial and multifamily assets, many of which are amenitized with ancillary retail. JBG SMITH's portfolio reflects its longstanding strategy of owning and operating assets within Metro-served submarkets in the Washington, D.C. metropolitan area that have high barriers to entry and key urban amenities, including National Landing where it serves as the exclusive developer for Amazon’s new headquarters. Substantially all of JBG SMITH's assets are held by, and its operations are conducted through, JBG SMITH Properties LP ("JBG SMITH LP"), its operating partnership. As of September 30, 2020, JBG SMITH, as its sole general partner, controlled JBG SMITH LP and owned 90.4% of its common limited partnership units ("OP Units"). JBG SMITH is hereinafter referred to as "we," "us," "our" or other similar terms. References to "our share" refer to our ownership percentage of consolidated and unconsolidated assets in real estate ventures. We were organized for the purpose of receiving, via the spin-off on July 17, 2017 (the "Separation"), substantially all of the assets and liabilities of Vornado Realty Trust's ("Vornado") Washington, D.C. segment. On July 18, 2017, we acquired the management business and certain assets and liabilities of The JBG Companies ("JBG") (the "Combination"). The Separation and the Combination are collectively referred to as the "Formation Transaction." As of September 30, 2020, our Operating Portfolio consisted of 64 operating assets comprising 43 commercial assets totaling 13.3 million square feet (11.2 million square feet at our share) and 21 multifamily assets totaling 7,800 units (5,999 units at our share). Additionally, we have (i) two under-construction assets comprising one wholly owned commercial asset totaling 274,000 square feet and one multifamily asset totaling 322 units (161 units at our share); (ii) 10 wholly owned near-term development assets totaling 5.6 million square feet of estimated potential development density; and (iii) 28 future development assets totaling 14.2 million square feet (11.5 million square feet at our share) of estimated potential development density. We derive our revenues primarily from leases with commercial and multifamily tenants, which include fixed and percentage rents, and reimbursements from tenants for certain expenses such as real estate taxes, property operating expenses, and repairs and maintenance. In addition, our third-party asset management and real estate services business provides fee-based real estate services to third parties, the Washington Housing Initiative ("WHI"), Amazon.com, Inc. ("Amazon") and the legacy funds formerly organized by JBG (the "JBG Legacy Funds"). Basis of Presentation The accompanying unaudited condensed consolidated financial statements and notes are prepared in accordance with accounting principles generally accepted in the United States of America ("GAAP") for interim financial information and with the instructions of Form 10-Q and Article 10 of Regulation S-X. Accordingly, these condensed consolidated financial statements do not contain certain information required in annual financial statements and notes as required under GAAP. In our opinion, all adjustments considered necessary for a fair presentation have been included, and all such adjustments are of a normal recurring nature. All intercompany transactions and balances have been eliminated. The results of operations for the three and nine months ended September 30, 2020 and 2019 are not necessarily indicative of the results that may be expected for a full year. These condensed consolidated financial statements should be read in conjunction with our Annual Report on Form 10-K for the year ended December 31, 2019, filed with the Securities and Exchange Commission. The accompanying condensed consolidated financial statements include our accounts and those of our wholly owned subsidiaries and other entities, including JBG SMITH LP, in which we have a controlling financial interest. See Note 5 for additional information on our variable interest entities ("VIEs"). The portions of the equity and net income (loss) of consolidated subsidiaries that are not attributable to JBG SMITH are presented separately as amounts attributable to noncontrolling interests in our condensed consolidated financial statements. References to our financial statements refer to our condensed consolidated financial statements as of September 30, 2020 and December 31, 2019, and for the three and nine months ended September 30, 2020 and 2019. References to our balance sheets refer to our condensed consolidated balance sheets as of September 30, 2020 and December 31, 2019. References to our statements of operations refer to our condensed consolidated statements of operations for the three and nine months ended September 30, 2020 and 2019. References to our statements of comprehensive income (loss) refer to our condensed consolidated statements of comprehensive income (loss) for the three and nine months ended September 30, 2020 and 2019. References to our statements of cash flows refer to our condensed consolidated statements of cash flows for the nine months ended September 30, 2020 and 2019. Income Taxes We have elected to be taxed as a REIT under sections 856-860 of the Internal Revenue Code of 1986, as amended (the "Code"). Under those sections, a REIT which distributes at least 90% of its REIT taxable income as dividends to its shareholders each year and which meets certain other conditions will not be taxed on that portion of its taxable income which is distributed to its shareholders. We intend to adhere to these requirements and maintain our REIT status in future periods. We also participate in the activities conducted by subsidiary entities which have elected to be treated as taxable REIT subsidiaries under the Code. As such, we are subject to federal, state and local taxes on the income from these activities. The Coronavirus Aid, Relief, and Economic Security Act (the "CARES Act") that was enacted on March 27, 2020 includes several significant tax provisions that could impact us and our taxable REIT subsidiaries ("TRSs"). These changes include: ● the elimination of the taxable income limit for net operating losses ("NOLs") for all taxable years beginning before January 1, 2021, thereby permitting corporate taxpayers to use NOLs to fully offset taxable income (although we, as a REIT, will continue to only be able to use NOLs against taxable income remaining after taking into account any dividends paid deduction); ● the ability for our TRSs to utilize carryback NOLs arising in 2018, 2019 and 2020 to the five taxable years preceding the taxable year of the loss; ● an increase of the business interest limitation under Section 163(j) of the Code from 30% to 50% for taxable years beginning in 2019 and 2020, and the addition of an election by taxpayers to use their 2019 adjusted taxable income as their adjusted taxable income in 2020 for purposes of applying the limitation; and ● a " technical correction " amending Section 168(e)(3)(E) of the Code to add "qualified improvement property" to "15-year property" and assigning a class life of 20-years under Section 168(g)(3)(B) of the Code to qualified improvement property under Section 168(e)(3)(E)(vii) of the Code . During the nine months ended September 30, 2020, as a result of the CARES Act, we made adjustments to the net deferred tax liability amounts, which relate to "qualified improvement property" owned by our TRSs.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2020
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Significant Accounting Policies There were no material changes to our significant accounting policies disclosed in our Annual Report on Form 10-K for the year ended December 31, 2019. Use of Estimates The preparation of the financial statements in conformity with GAAP requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities as of the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. The most significant of these estimates include: (i) the underlying cash flows and holding periods used in assessing impairment; (ii) the determination of useful lives for tangible and intangible assets; and (iii) the assessment of the collectability of receivables, including deferred rent receivables. Due to the current pandemic of the novel coronavirus, or COVID-19, commencing in March 2020, authorities in jurisdictions where our properties are located issued stay-at-home orders and restrictions on travel and permitted businesses operations. The effects of COVID-19 have most significantly impacted the operations of many of our retail tenants, which generated approximately 7% of our revenue for the year ended December 31, 2019, revenue from our multifamily assets, our commercial parking revenue and our interest in the operations of the Crystal City Marriott and The Marriott Wardman Park hotels. The extent to which COVID-19 impacts us and our tenants will depend on future developments, which are highly uncertain. At this time, there are no outstanding stay-at-home orders in jurisdictions where our properties are located; however, the extent and duration of restrictions on travel and permitted businesses operations and other effects of COVID-19 on us and our tenants have affected estimates used in the preparation of the underlying cash flows used in assessing our long-lived assets for impairment and the assessment of the collectability of receivables from tenants, including deferred rent receivables. We have made what we believe to be appropriate accounting estimates based on the facts and circumstances available as of the reporting date. To the extent these estimates differ from actual results, our consolidated financial statements may be materially affected. Recent Accounting Pronouncements Reference Rate Reform In March 2020, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update 2020-04, Reference Rate Reform ("Topic 848"). Topic 848 contains practical expedients for reference rate reform related activities that impact debt, leases, derivatives and other contracts. The guidance in Topic 848 is optional and may be elected over the period March 12, 2020 through December 31, 2022 as reference rate reform activities occur. ​ COVID-19 Lease Modification Accounting Relief Due to the business disruptions and challenges severely affecting the global economy caused by COVID-19, we have provided rent deferrals and other lease concessions to certain tenants. In April 2020, the FASB issued a Staff Q&A that allows lessors to elect not to evaluate whether lease-related relief provided to mitigate the economic effects of COVID-19 is a lease modification under Accounting Standards Codification Topic 842, Leases ("Topic 842") if certain criteria are met. This election allows us to bypass a lease-by-lease analysis, and instead choose whether to apply the lease modification accounting framework, with such election applied consistently to leases with similar characteristics and circumstances. We have elected to apply the lease modification policy relief and have accounted for lease-related relief provided to mitigate the economic effects of COVID-19 as lease modifications under Topic 842, regardless of whether the right to such relief was embedded within the terms of the lessee’s lease. During the three and nine months ended September 30, 2020, we entered into rent deferral agreements with certain tenants, many of which were placed on the cash basis of accounting, resulting in the deferral to future periods of $1.2 million and $2.4 million of rent that had been contractually due in the second and third quarters. We are in the process of negotiating additional rent deferrals and other lease concessions with some of our tenants, which have been considered when establishing credit losses against billed and deferred rent receivables. ​ During the three and nine months ended September 30, 2020, we recorded $3.2 million and $7.9 million of credit losses against billed rent receivables and $935,000 and $4.5 million against deferred (straight-line) rent receivables. These losses are due to the effects of COVID-19 primarily on retail tenants, that are unable to pay rent while businesses are closed or not operating at full capacity. During the second quarter of 2020, we also recorded $2.4 million of reserves against receivables from a parking operator that filed for bankruptcy protection. Additionally, during the second quarter of 2020, we determined that our investment in the venture that owns The Marriott Wardman Park hotel was impaired due to a decline in the fair value of the underlying asset and recorded an impairment charge of $6.5 million (see Note 4 for additional information). ​

Disposition and Assets Held for

Disposition and Assets Held for Sale	9 Months Ended
	Sep. 30, 2020
Discontinued Operations and Disposal Groups [Abstract]
Disposition and Assets Held for Sale	3. Disposition The following is a summary of disposition activity for the nine months ended September 30, 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gain on ​ ​ ​ ​ ​ ​ ​ ​ Total ​ Gross ​ Cash ​ Sale of ​ ​ ​ ​ ​ ​ ​ ​ Square ​ Sales ​ Proceeds ​ Real Date Disposed Assets Segment Location Feet Price from Sale Estate ​ ​ ​ ​ ​ ​ ​ ​ (In thousands) January 15, 2020 ​ Metropolitan Park (1) ​ Other ​ Arlington, Virginia ​ 2,150 ​ $ 154,952 ​ $ 154,493 ​ $ 59,477 (1) The property, which was sold to Amazon, was part of a like-kind exchange. See Note 5 for additional information. Total square feet represents potential development density approved by Arlington County. In June 2020, we recognized a loss of $3.0 million from the sale of 11333 Woodglen Drive/NoBe II Land/Woodglen ("Woodglen") by our unconsolidated real estate venture with Landmark Partners (“Landmark”). See Note 4 for additional information. Assets Held for Sale As of September 30, 2020 and December 31, 2019, certain real estate properties were classified as held for sale. The amounts included in "Assets held for sale" in our balance sheets primarily represent the carrying value of real estate. The following is a summary of assets held for sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total ​ Assets Held Assets Segment Location Square Feet (1) for Sale ​ ​ ​ ​ ​ ​ (In thousands) September 30, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ Pen Place (2) ​ Other ​ Arlington, Virginia ​ 2,080 ​ $ 74,089 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ Pen Place (2) ​ Other ​ Arlington, Virginia ​ 2,080 ​ $ 73,895 Metropolitan Park (3) ​ Other ​ Arlington, Virginia ​ 2,150 ​ ​ 94,517 ​ ​ ​ ​ ​ ​ 4,230 ​ $ 168,412 (1) Represents estimated or approved potential development density. (2) In March 2019, we entered into an agreement for the sale of Pen Place for $149.9 million, subject to customary closing conditions. We expect the sale of Pen Place to Amazon to close in 2021. (3) As noted above, we sold Metropolitan Park to Amazon in January 2020 . ​

Investments in Unconsolidated R

Investments in Unconsolidated Real Estate Ventures	9 Months Ended
	Sep. 30, 2020
Equity Method Investments and Joint Ventures [Abstract]
Investments in Unconsolidated Real Estate Ventures	4. Investments in Unconsolidated Real Estate Ventures The following is a summary of the composition of our investments in unconsolidated real estate ventures: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Ownership ​ ​ ​ Real Estate Venture Partners Interest (1) September 30, 2020 December 31, 2019 ​ ​ ​ ​ ​ (In thousands) ​ Prudential Global Investment Management 50.0% ​ $ 217,398 ​ $ 215,624 ​ Landmark 1.8% - 49.0% ​ 68,331 ​ 77,944 ​ CBREI Venture 5.0% - 64.0% ​ 65,598 ​ 68,405 ​ Canadian Pension Plan Investment Board ("CPPIB") (2) 55.0% ​ 48,041 ​ 109,911 ​ Berkshire Group 50.0% ​ 49,329 ​ ​ 46,391 ​ Brandywine Realty Trust 30.0% ​ 13,769 ​ 13,830 ​ Pacific Life Insurance Company (3) 20.0% ​ — ​ 10,385 ​ Other ​ ​ 560 ​ ​ 536 ​ Total investments in unconsolidated real estate ventures ​ ​ ​ $ 463,026 ​ $ 543,026 ​ (1) Ownership interests as of September 30, 2020. We have multiple investments with certain venture partners with varying ownership interests. (2) In April 2020, our real estate venture with CPPIB entered into a mortgage loan with a maximum principal balance of $160.0 million collateralized by 1900 N Street. The venture initially received proceeds of $134.5 million from the mortgage loan, with an additional $25.5 million available in the future. During the second quarter of 2020, we received a distribution of $70.8 million from the venture. (3) During the second quarter of 2020 , we determined that our investment in the venture that owns The Marriott Wardman Park hotel was impaired due to a decline in the fair value of the underlying asset and recorded an impairment charge of $6.5 million, which reduced the net book value of our investment to zero , and we suspended equity loss recognition for the venture after June 30, 2020. On October 1, 2020, we transferred our interest in this venture to our venture partner. In June 2020, our unconsolidated real estate venture with Landmark sold Woodglen, commercial and future development assets located in Rockville, Maryland, for $17.8 million. We recognized our proportionate share of the loss from the sale of $3.0 million, which is included in "Income (loss) from unconsolidated real estate ventures, net" in our statements of operations for the nine months ended September 30, 2020. Additionally, in connection with the sale, our unconsolidated real estate venture repaid the related mortgage payable of $12.2 million. We provide leasing, property management and other real estate services to our unconsolidated real estate ventures. We recognized revenue, including expense reimbursements, of $6.3 million and $19.3 million for the three and nine months ended September 30, 2020, and $7.2 million and $21.0 million for the three and nine months ended September 30, 2019 for such services. Reconsideration events could cause us to consolidate these unconsolidated real estate ventures in the future or deconsolidate a consolidated entity. We evaluate reconsideration events as we become aware of them. Reconsideration events include amendments to real estate venture agreements and changes in our partner's ability to make contributions to the venture. Under certain circumstances, we may purchase our partner's interest. The following is a summary of the debt of our unconsolidated real estate ventures: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ ​ ​ ​ ​ Average Effective ​ ​ ​ Interest Rate (1) September 30, 2020 December 31, 2019 ​ ​ ​ ​ (In thousands) Variable rate (2) 2.34% ​ $ 773,872 ​ $ 629,479 Fixed rate (3) (4) 3.79% ​ 444,775 ​ 561,236 Unconsolidated real estate ventures - mortgages payable ​ ​ ​ 1,218,647 ​ 1,190,715 Unamortized deferred financing costs ​ ​ ​ (7,437) ​ (2,859) Unconsolidated real estate ventures - mortgages payable, net (4) (5) ​ ​ ​ $ 1,211,210 ​ $ 1,187,856 (1) Weighted average effective interest rate as of September 30, 2020. (2) Includes variable rate mortgages payable with interest rate cap agreements. (3) Includes variable rate mortgages payable with interest rates fixed by interest rate swap agreements. (4) Excludes a $129.0 million mortgage loan collateralized by The Marriott Wardman Park hotel as of September 30, 2020. On October 1, 2020, we transferred our interest in the related venture to our venture partner. (5) See Note 17 for additional information on guarantees of the debt of certain of our unconsolidated real estate ventures. The following is a summary of the financial information for our unconsolidated real estate ventures: ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2020 December 31, 2019 ​ (In thousands) Combined balance sheet information: (1) ​ ​ ​ ​ ​ ​ Real estate, net ​ $ 2,287,736 ​ $ 2,493,961 Other assets, net ​ 274,321 ​ 291,092 Total assets ​ $ 2,562,057 ​ $ 2,785,053 ​ ​ ​ ​ ​ ​ ​ Borrowings, net ​ $ 1,211,210 ​ $ 1,187,856 Other liabilities, net ​ 143,939 ​ 168,243 Total liabilities ​ 1,355,149 ​ 1,356,099 Total equity ​ 1,206,908 ​ 1,428,954 Total liabilities and equity ​ $ 2,562,057 ​ $ 2,785,053 (1) Excludes all assets and liabilities related to The Marriott Wardman Park hotel as of September 30, 2020. On October 1, 2020, we transferred our interest in the related venture to our venture partner. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2020 2019 ​ 2020 2019 ​ (In thousands) Combined income statement information: (1) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total revenue ​ $ 47,235 ​ $ 65,110 ​ $ 162,128 ​ $ 199,897 Operating income (loss) (2) ​ ​ 1,296 ​ ​ 10,925 ​ (24,418) ​ 21,034 Net loss (2) ​ ​ (6,265) ​ ​ (3,602) ​ (60,331) ​ (20,289) (1) Excludes information related to the venture that owns The Marriott Wardman Park hotel for the three months ended September 30, 2020 as we suspended equity loss recognition for the venture after June 30, 2020. On October 1, 2020, we transferred our interest in the related venture to our venture partner. (2) Includes the loss from the sale of Woodglen of $16.4 million recognized by our unconsolidated real estate venture with Landmark during the nine months ended September 30, 2020.

Variable Interest Entities

Variable Interest Entities	9 Months Ended
	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Variable Interest Entities	5. We hold various interests in entities deemed to be VIEs, which we evaluate at acquisition, formation, after a change in the ownership agreement or after a change in the real estate venture's economics to determine if the VIEs should be consolidated in our financial statements or should no longer be considered a VIE. Certain criteria we assess in determining whether we are the primary beneficiary of the VIE and, therefore, should consolidate the VIE include our control over significant business activities, our voting rights and the noncontrolling interest kick-out rights. Unconsolidated VIEs As of September 30, 2020 and December 31, 2019, we had interests in entities deemed to be VIEs that are in the development stage and do not hold sufficient equity at risk, or conduct substantially all their operations on behalf of an investor with disproportionately few voting rights. Although we are engaged to act as the managing partner in charge of day-to-day operations of these investees, we are not the primary beneficiary of these VIEs, as we do not hold unilateral power over activities that, when taken together, most significantly impact the respective VIE's performance. We account for our investment in these entities under the equity method. As of September 30, 2020 and December 31, 2019, the net carrying amounts of our investment in these entities were $116.0 million and $242.9 million, which are included in "Investments in unconsolidated real estate ventures" in our balance sheets. Our equity in the income of unconsolidated VIEs is included in "Income (loss) from unconsolidated real estate ventures, net" in our statements of operations. Our maximum loss exposure in these entities is limited to our investments, construction commitments and certain guarantees. See Note 17 for additional information. Consolidated VIEs We consolidate a VIE when we control the significant business activities of an entity. An entity is a VIE because it is in the development stage and/or does not hold sufficient equity at risk. We are the primary beneficiary of a VIE because the noncontrolling interest holder does not have substantive kick-out or participating rights, and we control the significant business activities. JBG SMITH LP is our sole consolidated VIE. We hold 90.4% of the limited partnership interest in JBG SMITH LP, act as the general partner and exercise full responsibility, discretion and control over its day-to-day management. The noncontrolling interests of JBG SMITH LP do not have substantive liquidation rights, substantive kick-out rights without cause, or substantive participating rights that could be exercised by a simple majority of noncontrolling interest limited partners (including by such a limited partner unilaterally). Because the noncontrolling interest holders do not have these rights, JBG SMITH LP is a VIE. As general partner, we have the power to direct the activities of JBG SMITH LP that most significantly affect its performance, and through our majority interest, we have both the right to receive benefits from and the obligation to absorb losses of JBG SMITH LP. Accordingly, we are the primary beneficiary of JBG SMITH LP and consolidate it in our financial statements. Because we conduct our business and hold our assets and liabilities through JBG SMITH LP, its total assets and liabilities comprise substantially all of our consolidated assets and liabilities. In conjunction with the acquisition of F1RST Residences in December 2019, we entered into a like-kind exchange agreement with a third-party intermediary. As of December 31, 2019, the third-party intermediary was the legal owner of the entity that owned this property. We determined we were the primary beneficiary of the VIE, and accordingly, we consolidated the property and its operations as of the acquisition date. Legal ownership of this entity was transferred to us by the third-party intermediary when the like-kind exchange agreement was completed with the sale of Metropolitan Park in January 2020. During the second quarter of 2020, an under-construction multifamily asset at The Wren (formerly referred to as 965 Florida Avenue) in Washington, D.C. that we own through a consolidated real estate venture, which we had deemed to be a VIE, began placing units into service and commenced operations. We no longer deemed the real estate venture to be a VIE because it was determined to have sufficient equity to finance its activities without additional support. See Note 9 for additional information.

Other Assets, Net

Other Assets, Net	9 Months Ended
	Sep. 30, 2020
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Other Assets, Net	6. The following is a summary of other assets, net: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2020 December 31, 2019 ​ ​ (In thousands) Deferred leasing costs, net ​ $ 119,636 ​ $ 126,016 Lease intangible assets, net ​ 17,148 ​ 23,644 Management and leasing contracts, net ​ ​ 26,989 ​ ​ 31,515 Other identified intangible assets, net ​ 17,277 ​ 17,105 Operating lease right-of-use assets, net ​ 6,286 ​ 19,865 Finance lease right-of-use assets, net (1) ​ ​ 42,103 ​ ​ — Prepaid expenses ​ 20,372 ​ 12,556 Deferred financing costs on credit facility, net ​ 7,075 ​ 3,071 Deposits (2) ​ 28,410 ​ 3,210 Other ​ 16,718 ​ 16,705 Total other assets, net ​ $ 302,014 ​ $ 253,687 (1) Related to an amendment of the ground lease for 1730 M Street executed during the nine months ended September 30, 2020. The amendment extended the expiration date of the lease from April 2061 to December 2118, and resulted in its reclassification from an operating to a finance lease. (2) Includes deposits totaling $25.3 million with the Federal Communications Commission in connection with the acquisition of wireless spectrum licenses.

Debt

Debt	9 Months Ended
	Sep. 30, 2020
Debt Disclosure [Abstract]
Debt	7. Mortgages Payable The following is a summary of mortgages payable: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted Average ​ ​ ​ ​ ​ ​ ​ ​ ​ Effective ​ ​ ​ ​ Interest Rate (1) ​ September 30, 2020 December 31, 2019 ​ ​ ​ ​ ​ (In thousands) Variable rate (2) 2.18% ​ ​ $ 679,446 ​ $ 2,200 Fixed rate (3) 4.37% ​ ​ 1,021,825 ​ 1,125,648 Mortgages payable ​ ​ ​ ​ 1,701,271 ​ 1,127,848 Unamortized deferred financing costs and premium/ discount, net ​ ​ ​ ​ (10,548) ​ (2,071) Mortgages payable, net ​ ​ ​ ​ $ 1,690,723 ​ $ 1,125,777 (1) Weighted average effective interest rate as of September 30, 2020. (2) Includes variable rate mortgages payable with interest rate cap agreements. (3) Includes variable rate mortgages payable with interest rates fixed by interest rate swap agreements. As of September 30, 2020 and December 31, 2019, the net carrying value of real estate collateralizing our mortgages payable totaled $2.0 billion and $1.4 billion. Our mortgages payable contain covenants that limit our ability to incur additional indebtedness on these properties and, in certain circumstances, require lender approval of tenant leases and/or yield maintenance upon repayment prior to maturity. Certain mortgages payable are recourse to us. See Note 17 for additional information. During the nine months ended September 30, 2020, we entered into four separate mortgage loans with an aggregate principal balance of $560.0 million, collateralized by 4747 Bethesda Avenue, The Bartlett, 1221 Van Street and 220 20th Street, and refinanced the mortgage loan collateralized by RTC-West, increasing the principal balance by $20.2 million. As of September 30, 2020 and December 31, 2019, we had various interest rate swap and cap agreements on certain mortgages payable with an aggregate notional value of $1.3 billion and $867.6 million. See Note 15 for additional information. Credit Facility As of September 30, 2020, our $1.4 billion credit facility consisted of a $1.0 billion revolving credit facility maturing in January 2025, a $200.0 million unsecured term loan ("Tranche A-1 Term Loan") maturing in January 2023 and a $200.0 million unsecured term loan ("Tranche A-2 Term Loan") maturing in July 2024. The following is a summary of amounts outstanding under the credit facility: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Effective ​ ​ ​ ​ Interest Rate (1) ​ September 30, 2020 December 31, 2019 ​ ​ ​ ​ ​ (In thousands) Revolving credit facility (2) (3) (4) 1.20% ​ ​ $ — ​ $ 200,000 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Tranche A-1 Term Loan (5) 2.59% ​ ​ $ 200,000 ​ $ 100,000 Tranche A-2 Term Loan (6) 2.49% ​ ​ 200,000 ​ 200,000 Unsecured term loans ​ ​ 400,000 ​ 300,000 Unamortized deferred financing costs, net ​ ​ (2,192) ​ (2,705) Unsecured term loans, net ​ ​ $ 397,808 ​ $ 297,295 (1) Effective interest rate as of September 30, 2020. (2) As of both September 30, 2020 and December 31, 2019, letters of credit with an aggregate face amount of $1.5 million were outstanding under our revolving credit facility. (3) As of September 30, 2020 and December 31, 2019, net deferred financing costs related to our revolving credit facility totaling $7.1 million and $3.1 million were included in "Other assets, net." (4) The interest rate for our revolving credit facility excludes a 0.15% facility fee. (5) As of September 30, 2020 and December 31, 2019, $200.0 million and $100.0 million of the outstanding balance was fixed by interest rate swap agreements. The interest rate swaps mature concurrently with the term loan and provide a weighted average interest rate of 1.39% . (6) As of September 30, 2020 and December 31, 2019, $200.0 million and $137.6 million of the outstanding balance was fixed by interest rate swap agreements. As of September 30, 2020, the interest rate swaps mature concurrently with the term loan and provide a weighted average interest rate of 1.34% .

Other Liabilities, Net

Other Liabilities, Net	9 Months Ended
	Sep. 30, 2020
Other Liabilities Disclosure [Abstract]
Other Liabilities, Net	8. Other Liabilities, Net The following is a summary of other liabilities, net: ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2020 December 31, 2019 ​ ​ (In thousands) Lease intangible liabilities, net ​ $ 10,753 ​ $ 12,324 Lease assumption liabilities ​ 11,683 ​ 17,589 Lease incentive liabilities ​ 15,408 ​ 20,854 Liabilities related to operating lease right-of-use assets ​ 11,204 ​ 28,476 Liabilities related to finance lease right-of-use assets (1) ​ 40,049 ​ — Prepaid rent ​ 25,734 ​ 23,612 Security deposits ​ 14,431 ​ 16,348 Environmental liabilities ​ 17,898 ​ 17,898 Net deferred tax liability ​ 3,179 ​ 5,542 Dividends payable ​ — ​ 34,012 Derivative agreements, at fair value ​ 49,236 ​ 17,440 Other ​ 16,919 ​ 11,947 Total other liabilities, net ​ $ 216,494 ​ $ 206,042 (1) Related to an amendment of the ground lease for 1730 M Street executed during the nine months ended September 30, 2020. The amendment extended the expiration date of the lease from April 2061 to December 2118, and resulted in its reclassification from an operating to a finance lease.

Redeemable Noncontrolling Inter

Redeemable Noncontrolling Interests	9 Months Ended
	Sep. 30, 2020
Noncontrolling Interest [Abstract]
Redeemable Noncontrolling Interests	9. JBG SMITH LP OP Units held by persons other than JBG SMITH are redeemable for cash or, at our election, our common shares, subject to certain limitations. During the nine months ended September 30, 2020 and 2019, unitholders redeemed 1.1 million and 1.7 million OP Units, which we elected to redeem for an equivalent number of our common shares. As of September 30, 2020, outstanding OP Units totaled 14.0 million, representing a 9.6% ownership interest in JBG SMITH LP. On our balance sheets, our OP Units and certain vested long-term incentive partnership units ("LTIP Units") are presented at the higher of their redemption value or their carrying value, with such adjustments recognized in "Additional paid-in capital." Redemption value per OP Unit is equivalent to the market value of one of our common shares at the end of the period. In October 2020, unitholders redeemed 26,538 OP Units, which we elected to redeem for an equivalent number of our common shares. Consolidated Real Estate Venture We are a partner in a consolidated real estate venture that owns a multifamily asset located in Washington, D.C. Pursuant to the terms of the real estate venture agreement, we will fund all capital contributions until our ownership interest reaches a maximum of 97.0%. Our partner can redeem its interest for cash under certain conditions. As of September 30, 2020, we held a 95.9% ownership interest in the real estate venture. The following is a summary of the activity of redeemable noncontrolling interests: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ ​ 2020 ​ 2019 ​ ​ ​ ​ ​ Consolidated ​ ​ ​ ​ ​ ​ ​ Consolidated ​ ​ ​ ​ ​ JBG ​ Real Estate ​ ​ ​ ​ JBG ​ Real Estate ​ ​ ​ ​ SMITH LP Venture Total SMITH LP Venture Total ​ (In thousands) Balance as of the beginning of the period ​ $ 493,067 ​ $ 6,016 ​ $ 499,083 ​ $ 568,242 ​ $ 5,986 ​ $ 574,228 OP Unit redemptions ​ (4,796) ​ — ​ (4,796) ​ — ​ — ​ — Net income (loss) attributable to redeemable noncontrolling interests ​ (2,176) ​ (36) ​ (2,212) ​ 1,172 ​ — ​ 1,172 Other comprehensive income (loss) ​ 309 ​ — ​ 309 ​ (803) ​ — ​ (803) Distributions ​ (3,723) ​ — ​ (3,723) ​ (3,831) ​ — ​ (3,831) Share-based compensation expense ​ 14,496 ​ — ​ 14,496 ​ 14,320 ​ — ​ 14,320 Adjustment to redemption value ​ (14,012) ​ 1,776 ​ (12,236) ​ 1,446 ​ — ​ 1,446 Balance as of the end of the period ​ $ 483,165 ​ $ 7,756 ​ $ 490,921 ​ $ 580,546 ​ $ 5,986 ​ $ 586,532 ​ ​ Nine Months Ended September 30, ​ ​ 2020 ​ 2019 ​ ​ ​ ​ ​ Consolidated ​ ​ ​ ​ ​ ​ ​ Consolidated ​ ​ ​ ​ ​ JBG ​ Real Estate ​ ​ ​ ​ JBG ​ Real Estate ​ ​ ​ ​ SMITH LP Venture Total SMITH LP Venture Total ​ (In thousands) Balance as of the beginning of the period ​ $ 606,699 ​ $ 6,059 ​ $ 612,758 ​ $ 552,159 ​ $ 5,981 ​ $ 558,140 OP Unit redemptions ​ (40,674) ​ — ​ (40,674) ​ (57,318) ​ — ​ (57,318) LTIP Units issued in lieu of cash bonuses (1) ​ 4,066 ​ — ​ 4,066 ​ 3,954 ​ — ​ 3,954 Net income (loss) attributable to redeemable noncontrolling interests ​ (366) ​ (79) ​ (445) ​ 4,266 ​ 5 ​ 4,271 Other comprehensive income (loss) ​ (3,446) ​ — ​ (3,446) ​ (3,689) ​ — ​ (3,689) Distributions ​ (7,505) ​ — ​ (7,505) ​ (7,670) ​ — ​ (7,670) Share-based compensation expense ​ 51,742 ​ — ​ 51,742 ​ 45,937 ​ — ​ 45,937 Adjustment to redemption value ​ (127,351) ​ 1,776 ​ (125,575) ​ 42,907 ​ — ​ 42,907 Balance as of the end of the period ​ $ 483,165 ​ $ 7,756 ​ $ 490,921 ​ $ 580,546 ​ $ 5,986 ​ $ 586,532 (1) See Note 11 for additional information.

Property Rental Revenue

Property Rental Revenue	9 Months Ended
	Sep. 30, 2020
Property Rentals Revenue [Abstract]
Property Rental Revenue	10. Property Rental Revenue The following is a summary of property rental revenue from our non-cancellable leases: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2020 2019 ​ 2020 2019 ​ ​ (In thousands) Fixed ​ $ 109,321 ​ $ 114,538 ​ $ 326,866 ​ $ 342,268 Variable ​ ​ 9,359 ​ ​ 9,425 ​ ​ 27,653 ​ ​ 23,434 Property rental revenue ​ $ 118,680 ​ $ 123,963 ​ $ 354,519 ​ $ 365,702 ​

Share-Based Payments

Share-Based Payments	9 Months Ended
	Sep. 30, 2020
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-Based Payments	11. LTIP Units and Time-Based LTIP Units During the nine months ended September 30, 2020, we granted 381,504 LTIP Units with time-based vesting requirements ("Time-Based LTIP Units") to management and other employees with a weighted average grant-date fair value of $38.52 per unit that vest over four years, 25.0% per year, subject to continued employment. Compensation expense for these units is being recognized over a four-year period. The aggregate grant-date fair value of these Time-Based LTIP Units granted during the nine months ended September 30, 2020 was $14.7 million, valued using Monte Carlo simulations. During the nine months ended September 30, 2020, we granted 90,094 fully vested LTIP Units, with a grant-date fair value of $40.13 per unit, to certain executives who elected to receive all or a portion of their cash bonus paid in 2020, related to 2019 service, as LTIP Units. Compensation expense totaling $3.6 million for these LTIP Units was recognized in 2019. In April 2020, as part of their annual compensation, we granted a total of 54,607 fully vested LTIP Units to certain of our trustees with an aggregate grant-date fair value of $1.5 million. The following is a summary of the significant assumptions used to value the LTIP Units and Time-Based LTIP Units: ​ ​ ​ ​ Expected volatility 18.0% to 29.0% Risk-free interest rate 0.3% to 1.5% Post-grant restriction periods 2 to 3 years ​ Performance-Based LTIP Units During the nine months ended September 30, 2020, we granted 593,100 LTIP Units with performance-based vesting requirements ("Performance-Based LTIP Units") to management and other employees with a weighted average grant-date fair value of $18.67 per unit. Our Performance-Based LTIP Units have a three-year performance period. 50% of any Performance-Based LTIP Units that are earned vest at the end of the three-year performance period and the remaining 50% vest on the fourth anniversary of the date of grant, subject to continued employment. If, however, the Performance-Based LTIP Units do not achieve a positive absolute total shareholder return ("TSR") at the end of the three-year performance period, but satisfy the relative performance criteria thereof, 50% of the units that otherwise could have been earned will be forfeited, and the remaining 50% will be earned and vest if and when we achieve a positive TSR during the succeeding seven years, measured at the end of each quarter. The aggregate grant-date fair value of the Performance-Based LTIP Units granted during the nine months ended September 30, 2020 was $11.1 million, valued using Monte Carlo simulations. Compensation expense for the Performance-Based LTIP Units is being recognized over a four-year period. The following is a summary of the significant assumptions used to value the Performance-Based LTIP Units: ​ ​ ​ ​ Expected volatility 15.0% Dividend yield 2.3% Risk-free interest rate 1.3% ​ During the three months ended September 30, 2020, the three-year performance period ended for the Performance-Based LTIP Units granted on August 1, 2017. While our relative TSR over the three-year performance period would have allowed these grants to be fully earned, because our TSR over the three-year performance period was negative, 50% of the units (289,765 units) were forfeited, and the remaining 50% will be earned and vest if and when we achieve a positive TSR during the succeeding seven years. ESPP Pursuant to the ESPP, employees purchased 35,307 common shares for $887,000 during the nine months ended September 30, 2020. The following is a summary of the significant assumptions used to value the ESPP common shares using the Black-Scholes model: ​ ​ ​ ​ Expected volatility 13.0% Dividend yield 1.1% Risk-free interest rate 1.7% Expected life ​ 6 months ​ Share-Based Compensation Expense The following is a summary of share-based compensation expense: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2020 2019 ​ 2020 2019 ​ (In thousands) Time-Based LTIP Units ​ $ 3,364 ​ $ 2,755 ​ $ 11,003 ​ $ 8,529 Performance-Based LTIP Units ​ 3,999 ​ 2,016 ​ 14,207 ​ 6,205 LTIP Units ​ — ​ — ​ 1,100 ​ 1,000 Other equity awards (1) ​ 1,690 ​ 1,403 ​ 4,829 ​ 3,443 Share-based compensation expense - other ​ 9,053 ​ 6,174 ​ 31,139 ​ 19,177 Formation Awards ​ 875 ​ 1,227 ​ 3,473 ​ 4,116 OP Units (2) ​ 4,780 ​ 6,747 ​ 17,398 ​ 21,491 LTIP Units (2) ​ 95 ​ 117 ​ 310 ​ 340 Special Performance-Based LTIP Units (3) ​ 657 ​ 654 ​ 2,015 ​ 1,938 Special Time-Based LTIP Units (3) ​ 726 ​ 804 ​ 2,236 ​ 2,318 Share-based compensation related to Formation Transaction and special equity awards (4) ​ 7,133 ​ 9,549 ​ 25,432 ​ 30,203 Total share-based compensation expense ​ 16,186 ​ 15,723 ​ 56,571 ​ 49,380 Less amount capitalized ​ (1,177) ​ (406) ​ (3,388) ​ (1,948) Share-based compensation expense ​ $ 15,009 ​ $ 15,317 ​ $ 53,183 ​ $ 47,432 (1) Primarily comprising compensation expense for certain executives who have elected to receive all or a portion of any cash bonus that may be paid in the subsequent year related to past service in the form of fully vested LTIP Units and related to our ESPP. (2) Represents share-based compensation expense for LTIP Units and OP Units issued in the Formation Transaction, which are subject to post-Combination employment obligations. (3) Represents equity awards issued related to our successful pursuit of Amazon's additional headquarters in National Landing. (4) Included in "General and administrative expense: Share-based compensation related to Formation Transaction and special equity awards" in the accompanying statements of operations. As of September 30, 2020, we had $59.7 million of total unrecognized compensation expense related to unvested share-based payment arrangements, which is expected to be recognized over a weighted average period of 1.9 years.

Transaction and Other Costs

Transaction and Other Costs	9 Months Ended
	Sep. 30, 2020
Other Income and Expenses [Abstract]
Schedule of Transaction and Other Costs	12. The following is a summary of transaction and other costs: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2020 2019 ​ 2020 2019 ​ (In thousands) Demolition costs (1) ​ $ 179 ​ $ 503 ​ $ 179 ​ $ 4,693 Integration and severance costs ​ 406 ​ 1,021 ​ 3,066 ​ 4,274 Completed, potential and pursued transaction expenses ​ 260 ​ 535 ​ 281 ​ 961 Other (2) ​ — ​ — ​ 4,000 ​ — Transaction and other costs ​ $ 845 ​ $ 2,059 ​ $ 7,526 ​ $ 9,928 (1) Related to 223 23 rd Street and 2300 Crystal Drive for the three and nine months ended September 30, 2020. Related to 1900 Crystal Drive for the three and nine months ended September 30, 2019. (2) Represents a charitable commitment to the Washington Housing Conservancy, a non-profit that acquires and owns affordable workforce housing in the Washington D.C. metropolitan region.

Interest Expense

Interest Expense	9 Months Ended
	Sep. 30, 2020
Interest Expense [Abstract]
Schedule of Interest Expense	13. Interest Expense The following is a summary of interest expense: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2020 2019 ​ 2020 2019 ​ (In thousands) Interest expense before capitalized interest ​ $ 18,274 ​ $ 17,911 ​ $ 52,751 ​ $ 60,758 Amortization of deferred financing costs ​ 857 ​ 698 ​ 2,255 ​ 2,576 Interest expense related to finance lease right-of-use assets ​ ​ 464 ​ ​ 230 ​ ​ 1,026 ​ ​ 691 Net unrealized loss on derivative financial instruments not designated as cash flow hedges ​ 202 ​ 2 ​ 173 ​ 50 Capitalized interest ​ (2,912) ​ (8,258) ​ (11,545) ​ (23,211) Interest expense ​ $ 16,885 ​ $ 10,583 ​ $ 44,660 ​ $ 40,864 ​

Shareholders' Equity and Earnin

Shareholders' Equity and Earnings Per Common Share	9 Months Ended
	Sep. 30, 2020
Shareholders' Equity and Earnings Per Common Share
Shareholders' Equity and Earnings Per Common Share	14. Common Shares Repurchased In March 2020, our Board of Trustees authorized the repurchase of up to $500 million of our outstanding common shares. During the three and nine months ended September 30, 2020, we repurchased and retired 1.4 million and 2.9 million common shares for $38.4 million and $79.6 million, an average purchase price of $26.64 and $27.82 per share. Earnings Per Common Share ​ The following is a summary of the calculation of basic and diluted earnings per common share and a reconciliation of the amounts of net income (loss) available to common shareholders used in calculating basic and diluted earnings per common share to net income (loss): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ ​ 2020 2019 ​ 2020 2019 ​ ​ (In thousands, except per share amounts) Net income (loss) ​ $ (25,005) ​ $ 10,532 ​ $ (17,093) ​ $ 35,452 Net (income) loss attributable to redeemable noncontrolling interests ​ ​ 2,212 ​ (1,172) ​ 445 ​ (4,271) Net income (loss) attributable to common shareholders ​ ​ (22,793) ​ ​ 9,360 ​ ​ (16,648) ​ ​ 31,181 Distributions to participating securities ​ ​ (822) ​ ​ (679) ​ (1,729) ​ (1,674) Net income (loss) available to common shareholders — basic and diluted ​ $ (23,615) ​ $ 8,681 ​ $ (18,377) ​ $ 29,507 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted average number of common shares outstanding — basic and diluted ​ ​ 133,620 ​ ​ 134,127 ​ 133,924 ​ 129,527 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Earnings (loss) per common share: ​ ​ ​ ​ ​ ​ ​ ​ Basic ​ $ (0.18) ​ $ 0.06 ​ $ (0.14) ​ $ 0.23 Diluted ​ $ (0.18) ​ $ 0.06 ​ $ (0.14) ​ $ 0.23 ​ The effect of the redemption of OP Units and Time-Based LTIP Units that were outstanding as of September 30, 2020 and 2019 is excluded in the computation of diluted earnings per common share as the assumed exchange of such units for common shares on a one-for-one basis was antidilutive (the assumed redemption of these units would have no impact on the determination of diluted earnings per share). Since OP Units and Time-Based LTIP Units, which are held by noncontrolling interests, are attributed gains at an identical proportion to the common shareholders, the gains attributable and their equivalent weighted average OP Unit and Time-Based LTIP Unit impact are excluded from net income (loss) available to common shareholders and from the weighted average number of common shares outstanding in calculating diluted earnings per common share. Performance-Based LTIP Units, Special Performance-Based LTIP Units and Formation Awards, which totaled 4.4 million and 4.9 million for the three and nine months ended September 30, 2020, and 4.7 million for the three and nine months ended September 30, 2019, were excluded from the calculation of diluted earnings per common share as they were antidilutive, but potentially could be dilutive in the future.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	15. Fair Value Measurements on a Recurring Basis To manage or hedge our exposure to interest rate risk, we follow established risk management policies and procedures, including the use of a variety of derivative financial instruments. We do not enter into derivative financial instruments for speculative purposes. As of September 30, 2020 and December 31, 2019, we had various derivative financial instruments consisting of interest rate swap and cap agreements that are measured at fair value on a recurring basis. The net unrealized loss on our derivative financial instruments designated as cash flow hedges was $49.1 million and $17.7 million as of September 30, 2020 and December 31, 2019 and was recorded in "Accumulated other comprehensive loss" in our balance sheets, of which a portion was reclassified to "Redeemable noncontrolling interests." Within the next 12 months, we expect to reclassify $17.5 million as an increase to interest expense. Accounting Standards Codification 820 ("Topic 820"), Fair Value Measurement and Disclosures, defines fair value and establishes a framework for measuring fair value. The objective of fair value is to determine the price that would be received upon the sale of an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (the exit price). Topic 820 establishes a fair value hierarchy that prioritizes observable and unobservable inputs used to measure fair value into three levels: Level 1 — quoted prices (unadjusted) in active markets that are accessible at the measurement date for assets or liabilities; Level 2 — observable prices that are based on inputs not quoted in active markets, but corroborated by market data; and Level 3 — unobservable inputs that are used when little or no market data is available. The fair values of the derivative financial instruments are based on the estimated amounts we would receive or pay to terminate the contracts at the reporting date and are determined using interest rate pricing models and observable inputs. The derivative financial instruments are classified within Level 2 of the valuation hierarchy. The following is a summary of assets and liabilities measured at fair value on a recurring basis: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements ​ Total Level 1 Level 2 Level 3 ​ ​ (In thousands) September 30, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivative financial instruments designated as cash flow hedges: ​ ​ ​ ​ Classified as liabilities in "Other liabilities, net" ​ $ 49,236 ​ — ​ $ 49,236 ​ — Derivative financial instruments not designated as cash flow hedges: ​ ​ ​ ​ Classified as assets in "Other assets, net" ​ 47 ​ — ​ 47 ​ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ ​ Derivative financial instruments designated as cash flow hedges: ​ ​ ​ ​ Classified as liabilities in "Other liabilities, net" ​ $ 17,440 ​ — ​ $ 17,440 ​ — ​ The fair values of our derivative financial instruments were determined using widely accepted valuation techniques, including discounted cash flow analysis on the expected cash flows of the derivative financial instrument. This analysis reflected the contractual terms of the derivative, including the period to maturity, and used observable market-based inputs, including interest rate market data and implied volatilities in such interest rates. While it was determined that the majority of the inputs used to value the derivatives fall within Level 2 of the fair value hierarchy under authoritative accounting guidance, the credit valuation adjustments associated with the derivatives also utilized Level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default. However, as of September 30, 2020 and December 31, 2019, the significance of the impact of the credit valuation adjustments on the overall valuation of the derivative financial instruments was assessed, and it was determined that these adjustments were not significant to the overall valuation of the derivative financial instruments. As a result, it was determined that the derivative financial instruments in their entirety should be classified in Level 2 of the fair value hierarchy. The net unrealized gains and losses included in "Other comprehensive loss" in our statements of comprehensive income (loss) for the three and nine months ended September 30, 2020 and 2019 were attributable to the net change in unrealized gains or losses related to the interest rate swaps that were outstanding during those periods, none of which were reported in our statements of operations as the interest rate swaps were documented and qualified as hedging instruments. Financial Assets and Liabilities Not Measured at Fair Value As of September 30, 2020 and December 31, 2019, all financial instruments and liabilities were reflected in our balance sheets at amounts which, in our estimation, reasonably approximated their fair values, except for the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2020 ​ December 31, 2019 ​ Carrying ​ Carrying ​ ​ ​ Amount (1) ​ Fair Value ​ Amount (1) ​ Fair Value ​ (In thousands) Financial liabilities: ​ ​ ​ ​ Mortgages payable ​ $ 1,701,271 ​ $ 1,699,355 ​ $ 1,127,848 ​ $ 1,162,890 Revolving credit facility ​ — ​ — ​ 200,000 ​ 200,177 Unsecured term loans ​ 400,000 ​ 389,493 ​ 300,000 ​ 300,607 (1) The carrying amount consists of principal only. The fair values of the mortgages payable, revolving credit facility and unsecured term loans were determined using Level 2 inputs of the fair value hierarchy.

Segment Information

Segment Information	9 Months Ended
	Sep. 30, 2020
Segment Reporting [Abstract]
Segment Information	16. We review operating and financial data for each property on an individual basis; therefore, each of our individual properties is a separate operating segment. We define our reportable segments to be aligned with our method of internal reporting and the way our Chief Executive Officer, who is also our Chief Operating Decision Maker ("CODM"), makes key operating decisions, evaluates financial results, allocates resources and manages our business. Accordingly, we aggregate our operating segments into three reportable segments (commercial, multifamily, and third-party asset management and real estate services) based on the economic characteristics and nature of our assets and services. The CODM measures and evaluates the performance of our operating segments, with the exception of the third-party asset management and real estate services business, based on the net operating income ("NOI") of properties within each segment. NOI includes property rental revenue and other property revenue, and deducts property operating expenses and real estate taxes. With respect to the third-party asset management and real estate services business, the CODM reviews revenue streams generated by this segment ("Third-party real estate services, including reimbursements"), as well as the expenses attributable to the segment ("General and administrative: third-party real estate services"), which are both disclosed separately in our statements of operations. The following represents the components of revenue from our third-party real estate services business: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2020 2019 ​ 2020 2019 ​ (In thousands) Property management fees ​ $ 4,694 ​ $ 5,758 ​ $ 15,453 ​ $ 16,873 Asset management fees ​ 2,301 ​ 3,577 ​ 7,400 ​ 10,612 Development fees ​ 2,614 ​ 6,783 ​ 8,474 ​ 10,912 Leasing fees ​ 1,086 ​ 2,033 ​ 3,627 ​ 5,331 Construction management fees ​ 584 ​ 370 ​ 2,057 ​ 1,469 Other service revenue ​ 2,000 ​ 1,005 ​ 5,452 ​ 3,626 Third-party real estate services revenue, excluding reimbursements ​ 13,279 ​ 19,526 ​ 42,463 ​ 48,823 Reimbursements revenue (1) ​ 13,708 ​ 15,061 ​ 41,407 ​ 42,942 Third-party real estate services revenue, including reimbursements ​ ​ 26,987 ​ ​ 34,587 ​ ​ 83,870 ​ ​ 91,765 Third-party real estate services expenses ​ ​ 28,207 ​ ​ 29,809 ​ ​ 86,260 ​ ​ 86,585 Third-party real estate services revenue less expenses ​ $ (1,220) ​ $ 4,778 ​ $ (2,390) ​ $ 5,180 (1) Represents reimbursement of expenses incurred by us on behalf of third parties, including allocated payroll costs and amounts paid to third-party contractors for construction management projects. Management company assets primarily consist of management and leasing contracts with a net book value of $27.0 million and $31.5 million and are classified in "Other assets, net" in our balance sheets as of September 30, 2020 and December 31, 2019. Consistent with internal reporting presented to our CODM and our definition of NOI, the third-party asset management and real estate services operating results are excluded from the NOI data below. The following is the reconciliation of net income (loss) attributable to common shareholders to consolidated NOI: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2020 2019 ​ 2020 2019 ​ (In thousands) Net income (loss) attributable to common shareholders ​ $ (22,793) ​ $ 9,360 ​ $ (16,648) ​ $ 31,181 Add: ​ ​ ​ ​ Depreciation and amortization expense ​ 56,481 ​ 46,862 ​ 157,586 ​ 141,576 General and administrative expense: ​ ​ ​ ​ Corporate and other ​ 11,086 ​ 11,015 ​ 37,478 ​ 34,888 Third-party real estate services ​ 28,207 ​ 29,809 ​ 86,260 ​ 86,585 Share-based compensation related to Formation Transaction and special equity awards ​ 7,133 ​ 9,549 ​ 25,432 ​ 30,203 Transaction and other costs ​ 845 ​ 2,059 ​ 7,526 ​ 9,928 Interest expense ​ 16,885 ​ 10,583 ​ 44,660 ​ 40,864 Loss on extinguishment of debt ​ — ​ — ​ 33 ​ 1,889 Income tax expense (benefit) ​ (488) ​ 432 ​ (3,721) ​ (689) Net income (loss) attributable to redeemable noncontrolling interests ​ (2,212) ​ 1,172 ​ (445) ​ 4,271 Less: ​ ​ ​ ​ Third-party real estate services, including reimbursements revenue ​ 26,987 ​ 34,587 ​ 83,870 ​ 91,765 Other revenue (1) ​ 2,292 ​ 2,196 ​ 5,438 ​ 5,951 Income (loss) from unconsolidated real estate ventures, net ​ (965) ​ (1,144) ​ (17,142) ​ 647 Interest and other income (loss), net ​ — ​ (640) ​ 1,021 ​ 2,363 Gain on sale of real estate ​ — ​ 8,088 ​ 59,477 ​ 47,121 Consolidated NOI ​ $ 66,830 ​ $ 77,754 ​ $ 205,497 ​ $ 232,849 (1) Excludes parking revenue of $3.1 million and $10.3 million for the three and nine months ended September 30, 2020, and $6.3 million and $19.5 million for the three and nine months ended September 30, 2019. The following is a summary of NOI by segment. Items classified in the Other column include future development assets, corporate entities and the elimination of intersegment activity. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, 2020 ​ Commercial Multifamily Other Total ​ (In thousands) Property rental revenue ​ $ 90,050 ​ $ 30,452 ​ $ (1,822) ​ $ 118,680 Other property revenue ​ 3,002 ​ 74 ​ — ​ 3,076 Total property revenue ​ 93,052 ​ 30,526 ​ (1,822) ​ 121,756 Property expense: ​ ​ ​ ​ ​ ​ ​ Property operating ​ 26,701 ​ 13,226 ​ (2,355) ​ 37,572 Real estate taxes ​ 12,136 ​ 4,656 ​ 562 ​ 17,354 Total property expense ​ 38,837 ​ 17,882 ​ (1,793) ​ 54,926 Consolidated NOI ​ $ 54,215 ​ $ 12,644 ​ $ (29) ​ $ 66,830 ​ ​ Three Months Ended September 30, 2019 ​ Commercial Multifamily Other Total ​ (In thousands) Property rental revenue ​ $ 94,678 ​ $ 28,946 ​ $ 339 ​ $ 123,963 Other property revenue ​ 6,237 ​ 94 ​ — ​ 6,331 Total property revenue ​ 100,915 ​ 29,040 ​ 339 ​ 130,294 Property expense: ​ ​ ​ ​ ​ Property operating ​ 27,200 ​ 9,490 ​ (890) ​ 35,800 Real estate taxes ​ 12,004 ​ 3,552 ​ 1,184 ​ 16,740 Total property expense ​ 39,204 ​ 13,042 ​ 294 ​ 52,540 Consolidated NOI ​ $ 61,711 ​ $ 15,998 ​ $ 45 ​ $ 77,754 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, 2020 ​ Commercial Multifamily Other Total ​ (In thousands) Property rental revenue ​ $ 266,823 ​ $ 94,873 ​ $ (7,177) ​ $ 354,519 Other property revenue ​ 10,018 ​ 249 ​ — ​ 10,267 Total property revenue ​ 276,841 ​ 95,122 ​ (7,177) ​ 364,786 Property expense: ​ ​ ​ ​ ​ Property operating ​ 78,645 ​ 34,238 ​ (7,016) ​ 105,867 Real estate taxes ​ 36,532 ​ 14,088 ​ 2,802 ​ 53,422 Total property expense ​ 115,177 ​ 48,326 ​ (4,214) ​ 159,289 Consolidated NOI ​ $ 161,664 ​ $ 46,796 ​ $ (2,963) ​ $ 205,497 ​ ​ Nine Months Ended September 30, 2019 ​ Commercial Multifamily Other Total ​ ​ (In thousands) Property rental revenue ​ $ 285,551 ​ $ 86,069 ​ $ (5,918) ​ $ 365,702 Other property revenue ​ 19,212 ​ 263 ​ — ​ 19,475 Total property revenue ​ 304,763 ​ 86,332 ​ (5,918) ​ 385,177 Property expense: ​ ​ ​ ​ Property operating ​ 84,089 ​ 25,662 ​ (9,664) ​ 100,087 Real estate taxes ​ 37,257 ​ 11,243 ​ 3,741 ​ 52,241 Total property expense ​ 121,346 ​ 36,905 ​ (5,923) ​ 152,328 Consolidated NOI ​ $ 183,417 ​ $ 49,427 ​ $ 5 ​ $ 232,849 ​ The following is a summary of certain balance sheet data by segment: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial Multifamily Other Total ​ ​ (In thousands) September 30, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Real estate, at cost ​ $ 3,506,113 ​ $ 2,034,045 ​ $ 400,497 ​ $ 5,940,655 Investments in unconsolidated real estate ventures ​ 330,111 ​ 108,110 ​ 24,805 ​ 463,026 Total assets (1) ​ 3,473,426 ​ 1,798,714 ​ 1,005,184 ​ 6,277,324 December 31, 2019 ​ ​ ​ ​ Real estate, at cost ​ $ 3,415,294 ​ $ 1,998,297 ​ $ 361,928 ​ $ 5,775,519 Investments in unconsolidated real estate ventures ​ 396,199 ​ 107,882 ​ 38,945 ​ 543,026 Total assets (1) ​ 3,361,122 ​ 1,682,872 ​ 942,257 ​ 5,986,251 (1) Includes assets held for sale. See Note 3 for additional information.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	17. Commitments and Contingencies Insurance We maintain general liability insurance with limits of $150.0 million per occurrence and in the aggregate, and property and rental value insurance coverage with limits of $1.5 billion per occurrence, with sub-limits for certain perils such as floods and earthquakes on each of our properties. We also maintain coverage, through our wholly owned captive insurance subsidiary, for a portion of the first loss on the above limits and for both terrorist acts and for nuclear, biological, chemical or radiological terrorism events with limits of $2.0 billion per occurrence. These policies are partially reinsured by third-party insurance providers. We will continue to monitor the state of the insurance market, and the scope and costs of coverage for acts of terrorism. We cannot anticipate what coverage will be available on commercially reasonable terms in the future. We are responsible for deductibles and losses in excess of the insurance coverage, which could be material. Our debt, consisting of mortgages payable secured by our properties, a revolving credit facility and unsecured term loans, contains customary covenants requiring adequate insurance coverage. Although we believe that we currently have adequate insurance coverage, we may not be able to obtain an equivalent amount of coverage at reasonable costs in the future. If lenders insist on greater coverage than we are able to obtain, it could adversely affect the ability to finance or refinance our properties. Construction Commitments As of September 30, 2020, we had construction in progress that will require an additional $34.0 million to complete ($20.2 million related to our consolidated entities and $13.8 million related to our unconsolidated real estate ventures at our share), based on our current plans and estimates, which we anticipate will be primarily expended over the next one Environmental Matters Most of our assets have been subject, at some point, to environmental assessments that are intended to evaluate the environmental condition of the subject and surrounding assets. The environmental assessments did not reveal any material environmental contamination that we believe would have a material adverse effect on our overall business, financial condition or results of operations, or that have not been anticipated and remediated during site redevelopment as required by law. Nevertheless, there can be no assurance that the identification of new areas of contamination, changes in the extent or known scope of contamination, the discovery of additional sites or changes in cleanup requirements would not result in significant cost to us. Environmental liabilities totaled $17.9 million as of both September 30, 2020 and December 31, 2019 and are included in "Other liabilities, net" in our balance sheets. Other There are various legal actions against us in the ordinary course of business. In our opinion, the outcome of such matters will not have a material adverse effect on our financial condition, results of operations or cash flows. From time to time, we (or ventures in which we have an ownership interest) have agreed, and may in the future agree with respect to unconsolidated real estate ventures, to (i) guarantee portions of the principal, interest and other amounts in connection with borrowings, (ii) provide customary environmental indemnifications and nonrecourse carve-outs (e.g., guarantees against fraud, misrepresentation and bankruptcy) in connection with borrowings or (iii) provide guarantees to lenders and other third parties for the completion of development projects. We customarily have agreements with our outside venture partners whereby the partners agree to reimburse the real estate venture or us for their share of any payments made under certain of these guarantees. At times, we also have agreements with certain of our outside venture partners whereby we agree to either indemnify the partners and/or the associated ventures with respect to certain contingent liabilities associated with operating assets or to reimburse our partner for its share of any payments made by them under certain guarantees. Guarantees (excluding environmental) customarily terminate either upon the satisfaction of specified circumstances or repayment of the underlying debt. Amounts that we may be required to pay in future periods in relation to guarantees associated with budget overruns or operating losses are not estimable. As of September 30, 2020, we had additional capital commitments and certain recorded guarantees to our unconsolidated real estate ventures totaling $56.9 million. As of September 30, 2020, we had no principal payment guarantees related to our unconsolidated real estate ventures. ​ Additionally, with respect to borrowings of our consolidated entities, we have agreed, and may in the future agree, to (i) guarantee portions of the principal, interest and other amounts, (ii) provide customary environmental indemnifications and nonrecourse carve-outs (e.g., guarantees against fraud, misrepresentation and bankruptcy) or (iii) provide guarantees to lenders, tenants and other third parties for the completion of development projects. In connection with the Formation Transaction, we have an agreement with Vornado regarding tax matters (the "Tax Matters Agreement") that provides special rules that allocate tax liabilities if the distribution of JBG SMITH shares by Vornado, together with certain related transactions, is determined not to be tax-free. Under the Tax Matters Agreement, we may be required to indemnify Vornado against any taxes and related amounts and costs resulting from a violation by us of the Tax Matters Agreement.

Transactions with Related Parti

Transactions with Related Parties	9 Months Ended
	Sep. 30, 2020
Related Party Transactions [Abstract]
Transactions with Related Parties	18. Our third-party asset management and real estate services business provides fee-based real estate services to third parties, the WHI, Amazon and the JBG Legacy Funds. We provide services for the benefit of the JBG Legacy Funds that own interests in the assets retained by the JBG Legacy Funds. In connection with the contribution to us of the assets formerly owned by the JBG Legacy Funds as part of the Formation Transaction, the general partner and managing member interests in the JBG Legacy Funds that were held by certain former JBG executives (and who became members of our management team and/or Board of Trustees) were not transferred to us and remain under the control of these individuals. In addition, certain members of our senior management and Board of Trustees have an ownership interest in the JBG Legacy Funds and own carried interests in each fund and in certain of our real estate ventures that entitle them to receive cash payments if the fund or real estate venture achieves certain return thresholds. The WHI was launched by us and the Federal City Council in June 2018 as a scalable market-driven model that uses private capital to help address the scarcity of housing for middle income families. We are the manager for the WHI Impact Pool, which is the social impact investment vehicle of the WHI. As of September 30, 2020, the WHI Impact Pool had completed closings of capital commitments totaling $112.0 million, which included a commitment from us of $10.9 million. The third-party real estate services revenue, including expense reimbursements, from the JBG Legacy Funds and the WHI Impact Pool was $4.6 million and $17.3 million for the three and nine months ended September 30, 2020, and $10.2 million and $28.6 million for the three and nine months ended September 30, 2019. As of September 30, 2020 and December 31, 2019, we had receivables from the JBG Legacy Funds and the WHI Impact Pool totaling $8.1 million and $6.2 million for such services. We rented our former corporate offices from an unconsolidated real estate venture and made payments totaling $403,000 and $4.1 million for the three and nine months ended September 30, 2020, and $867,000 and $3.4 million for the three and nine months ended September 30, 2019. In November 2019, we relocated our corporate headquarters. Upon the relocation of our corporate headquarters, we impaired the right-of-use asset due to our change in the use of the asset. ​ We have agreements with Building Maintenance Services ("BMS"), an entity in which we have a minor preferred interest, to supervise cleaning, engineering and security services at our properties. We paid BMS $4.0 million and $12.6 million during the three and nine months ended September 30, 2020, and $5.5 million and $16.1 million during the three and nine months ended September 30, 2019 which is included in "Property operating expenses" in our statements of operations.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2020
Subsequent Events [Abstract]
Subsequent Events	19. On October 29, 2020, our Board of Trustees declared a quarterly dividend of $0.225 per common share, payable on November 30, 2020 to shareholders of record as of November 13, 2020.

Organization and Basis of Pre_2

Organization and Basis of Presentation Accounting (Policies)	9 Months Ended
	Sep. 30, 2020
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements and notes are prepared in accordance with accounting principles generally accepted in the United States of America ("GAAP") for interim financial information and with the instructions of Form 10-Q and Article 10 of Regulation S-X. Accordingly, these condensed consolidated financial statements do not contain certain information required in annual financial statements and notes as required under GAAP. In our opinion, all adjustments considered necessary for a fair presentation have been included, and all such adjustments are of a normal recurring nature. All intercompany transactions and balances have been eliminated. The results of operations for the three and nine months ended September 30, 2020 and 2019 are not necessarily indicative of the results that may be expected for a full year. These condensed consolidated financial statements should be read in conjunction with our Annual Report on Form 10-K for the year ended December 31, 2019, filed with the Securities and Exchange Commission. The accompanying condensed consolidated financial statements include our accounts and those of our wholly owned subsidiaries and other entities, including JBG SMITH LP, in which we have a controlling financial interest. See Note 5 for additional information on our variable interest entities ("VIEs"). The portions of the equity and net income (loss) of consolidated subsidiaries that are not attributable to JBG SMITH are presented separately as amounts attributable to noncontrolling interests in our condensed consolidated financial statements. References to our financial statements refer to our condensed consolidated financial statements as of September 30, 2020 and December 31, 2019, and for the three and nine months ended September 30, 2020 and 2019. References to our balance sheets refer to our condensed consolidated balance sheets as of September 30, 2020 and December 31, 2019. References to our statements of operations refer to our condensed consolidated statements of operations for the three and nine months ended September 30, 2020 and 2019. References to our statements of comprehensive income (loss) refer to our condensed consolidated statements of comprehensive income (loss) for the three and nine months ended September 30, 2020 and 2019. References to our statements of cash flows refer to our condensed consolidated statements of cash flows for the nine months ended September 30, 2020 and 2019.
Income Taxes	Income Taxes We have elected to be taxed as a REIT under sections 856-860 of the Internal Revenue Code of 1986, as amended (the "Code"). Under those sections, a REIT which distributes at least 90% of its REIT taxable income as dividends to its shareholders each year and which meets certain other conditions will not be taxed on that portion of its taxable income which is distributed to its shareholders. We intend to adhere to these requirements and maintain our REIT status in future periods. We also participate in the activities conducted by subsidiary entities which have elected to be treated as taxable REIT subsidiaries under the Code. As such, we are subject to federal, state and local taxes on the income from these activities. The Coronavirus Aid, Relief, and Economic Security Act (the "CARES Act") that was enacted on March 27, 2020 includes several significant tax provisions that could impact us and our taxable REIT subsidiaries ("TRSs"). These changes include: ● the elimination of the taxable income limit for net operating losses ("NOLs") for all taxable years beginning before January 1, 2021, thereby permitting corporate taxpayers to use NOLs to fully offset taxable income (although we, as a REIT, will continue to only be able to use NOLs against taxable income remaining after taking into account any dividends paid deduction); ● the ability for our TRSs to utilize carryback NOLs arising in 2018, 2019 and 2020 to the five taxable years preceding the taxable year of the loss; ● an increase of the business interest limitation under Section 163(j) of the Code from 30% to 50% for taxable years beginning in 2019 and 2020, and the addition of an election by taxpayers to use their 2019 adjusted taxable income as their adjusted taxable income in 2020 for purposes of applying the limitation; and ● a " technical correction " amending Section 168(e)(3)(E) of the Code to add "qualified improvement property" to "15-year property" and assigning a class life of 20-years under Section 168(g)(3)(B) of the Code to qualified improvement property under Section 168(e)(3)(E)(vii) of the Code . During the nine months ended September 30, 2020, as a result of the CARES Act, we made adjustments to the net deferred tax liability amounts, which relate to "qualified improvement property" owned by our TRSs.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2020
Accounting Policies [Abstract]
Use of Estimates	Use of Estimates The preparation of the financial statements in conformity with GAAP requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities as of the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. The most significant of these estimates include: (i) the underlying cash flows and holding periods used in assessing impairment; (ii) the determination of useful lives for tangible and intangible assets; and (iii) the assessment of the collectability of receivables, including deferred rent receivables. Due to the current pandemic of the novel coronavirus, or COVID-19, commencing in March 2020, authorities in jurisdictions where our properties are located issued stay-at-home orders and restrictions on travel and permitted businesses operations. The effects of COVID-19 have most significantly impacted the operations of many of our retail tenants, which generated approximately 7% of our revenue for the year ended December 31, 2019, revenue from our multifamily assets, our commercial parking revenue and our interest in the operations of the Crystal City Marriott and The Marriott Wardman Park hotels. The extent to which COVID-19 impacts us and our tenants will depend on future developments, which are highly uncertain. At this time, there are no outstanding stay-at-home orders in jurisdictions where our properties are located; however, the extent and duration of restrictions on travel and permitted businesses operations and other effects of COVID-19 on us and our tenants have affected estimates used in the preparation of the underlying cash flows used in assessing our long-lived assets for impairment and the assessment of the collectability of receivables from tenants, including deferred rent receivables. We have made what we believe to be appropriate accounting estimates based on the facts and circumstances available as of the reporting date. To the extent these estimates differ from actual results, our consolidated financial statements may be materially affected.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Reference Rate Reform In March 2020, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update 2020-04, Reference Rate Reform ("Topic 848"). Topic 848 contains practical expedients for reference rate reform related activities that impact debt, leases, derivatives and other contracts. The guidance in Topic 848 is optional and may be elected over the period March 12, 2020 through December 31, 2022 as reference rate reform activities occur. ​ COVID-19 Lease Modification Accounting Relief Due to the business disruptions and challenges severely affecting the global economy caused by COVID-19, we have provided rent deferrals and other lease concessions to certain tenants. In April 2020, the FASB issued a Staff Q&A that allows lessors to elect not to evaluate whether lease-related relief provided to mitigate the economic effects of COVID-19 is a lease modification under Accounting Standards Codification Topic 842, Leases ("Topic 842") if certain criteria are met. This election allows us to bypass a lease-by-lease analysis, and instead choose whether to apply the lease modification accounting framework, with such election applied consistently to leases with similar characteristics and circumstances. We have elected to apply the lease modification policy relief and have accounted for lease-related relief provided to mitigate the economic effects of COVID-19 as lease modifications under Topic 842, regardless of whether the right to such relief was embedded within the terms of the lessee’s lease. During the three and nine months ended September 30, 2020, we entered into rent deferral agreements with certain tenants, many of which were placed on the cash basis of accounting, resulting in the deferral to future periods of $1.2 million and $2.4 million of rent that had been contractually due in the second and third quarters. We are in the process of negotiating additional rent deferrals and other lease concessions with some of our tenants, which have been considered when establishing credit losses against billed and deferred rent receivables. ​ During the three and nine months ended September 30, 2020, we recorded $3.2 million and $7.9 million of credit losses against billed rent receivables and $935,000 and $4.5 million against deferred (straight-line) rent receivables. These losses are due to the effects of COVID-19 primarily on retail tenants, that are unable to pay rent while businesses are closed or not operating at full capacity. During the second quarter of 2020, we also recorded $2.4 million of reserves against receivables from a parking operator that filed for bankruptcy protection. Additionally, during the second quarter of 2020, we determined that our investment in the venture that owns The Marriott Wardman Park hotel was impaired due to a decline in the fair value of the underlying asset and recorded an impairment charge of $6.5 million (see Note 4 for additional information).

Disposition and Assets Held f_2

Disposition and Assets Held for Sale (Tables)	9 Months Ended
	Sep. 30, 2020
Discontinued Operations and Disposal Groups [Abstract]
Summary of disposition activity	The following is a summary of disposition activity for the nine months ended September 30, 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gain on ​ ​ ​ ​ ​ ​ ​ ​ Total ​ Gross ​ Cash ​ Sale of ​ ​ ​ ​ ​ ​ ​ ​ Square ​ Sales ​ Proceeds ​ Real Date Disposed Assets Segment Location Feet Price from Sale Estate ​ ​ ​ ​ ​ ​ ​ ​ (In thousands) January 15, 2020 ​ Metropolitan Park (1) ​ Other ​ Arlington, Virginia ​ 2,150 ​ $ 154,952 ​ $ 154,493 ​ $ 59,477 (1) The property, which was sold to Amazon, was part of a like-kind exchange. See Note 5 for additional information. Total square feet represents potential development density approved by Arlington County.
Summary of assets held for sale	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total ​ Assets Held Assets Segment Location Square Feet (1) for Sale ​ ​ ​ ​ ​ ​ (In thousands) September 30, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ Pen Place (2) ​ Other ​ Arlington, Virginia ​ 2,080 ​ $ 74,089 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ Pen Place (2) ​ Other ​ Arlington, Virginia ​ 2,080 ​ $ 73,895 Metropolitan Park (3) ​ Other ​ Arlington, Virginia ​ 2,150 ​ ​ 94,517 ​ ​ ​ ​ ​ ​ 4,230 ​ $ 168,412 (1) Represents estimated or approved potential development density. (2) In March 2019, we entered into an agreement for the sale of Pen Place for $149.9 million, subject to customary closing conditions. We expect the sale of Pen Place to Amazon to close in 2021. (3) As noted above, we sold Metropolitan Park to Amazon in January 2020 .

Investments in Unconsolidated_2

Investments in Unconsolidated Real Estate Ventures (Tables)	9 Months Ended
	Sep. 30, 2020
Equity Method Investments and Joint Ventures [Abstract]
Summary of Unconsolidated Investments	The following is a summary of the composition of our investments in unconsolidated real estate ventures: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Ownership ​ ​ ​ Real Estate Venture Partners Interest (1) September 30, 2020 December 31, 2019 ​ ​ ​ ​ ​ (In thousands) ​ Prudential Global Investment Management 50.0% ​ $ 217,398 ​ $ 215,624 ​ Landmark 1.8% - 49.0% ​ 68,331 ​ 77,944 ​ CBREI Venture 5.0% - 64.0% ​ 65,598 ​ 68,405 ​ Canadian Pension Plan Investment Board ("CPPIB") (2) 55.0% ​ 48,041 ​ 109,911 ​ Berkshire Group 50.0% ​ 49,329 ​ ​ 46,391 ​ Brandywine Realty Trust 30.0% ​ 13,769 ​ 13,830 ​ Pacific Life Insurance Company (3) 20.0% ​ — ​ 10,385 ​ Other ​ ​ 560 ​ ​ 536 ​ Total investments in unconsolidated real estate ventures ​ ​ ​ $ 463,026 ​ $ 543,026 ​ (1) Ownership interests as of September 30, 2020. We have multiple investments with certain venture partners with varying ownership interests. (2) In April 2020, our real estate venture with CPPIB entered into a mortgage loan with a maximum principal balance of $160.0 million collateralized by 1900 N Street. The venture initially received proceeds of $134.5 million from the mortgage loan, with an additional $25.5 million available in the future. During the second quarter of 2020, we received a distribution of $70.8 million from the venture. (3) During the second quarter of 2020 , we determined that our investment in the venture that owns The Marriott Wardman Park hotel was impaired due to a decline in the fair value of the underlying asset and recorded an impairment charge of $6.5 million, which reduced the net book value of our investment to zero , and we suspended equity loss recognition for the venture after June 30, 2020. On October 1, 2020, we transferred our interest in this venture to our venture partner. The following is a summary of the debt of our unconsolidated real estate ventures: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ ​ ​ ​ ​ Average Effective ​ ​ ​ Interest Rate (1) September 30, 2020 December 31, 2019 ​ ​ ​ ​ (In thousands) Variable rate (2) 2.34% ​ $ 773,872 ​ $ 629,479 Fixed rate (3) (4) 3.79% ​ 444,775 ​ 561,236 Unconsolidated real estate ventures - mortgages payable ​ ​ ​ 1,218,647 ​ 1,190,715 Unamortized deferred financing costs ​ ​ ​ (7,437) ​ (2,859) Unconsolidated real estate ventures - mortgages payable, net (4) (5) ​ ​ ​ $ 1,211,210 ​ $ 1,187,856 (1) Weighted average effective interest rate as of September 30, 2020. (2) Includes variable rate mortgages payable with interest rate cap agreements. (3) Includes variable rate mortgages payable with interest rates fixed by interest rate swap agreements. (4) Excludes a $129.0 million mortgage loan collateralized by The Marriott Wardman Park hotel as of September 30, 2020. On October 1, 2020, we transferred our interest in the related venture to our venture partner. (5) See Note 17 for additional information on guarantees of the debt of certain of our unconsolidated real estate ventures. ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2020 December 31, 2019 ​ (In thousands) Combined balance sheet information: (1) ​ ​ ​ ​ ​ ​ Real estate, net ​ $ 2,287,736 ​ $ 2,493,961 Other assets, net ​ 274,321 ​ 291,092 Total assets ​ $ 2,562,057 ​ $ 2,785,053 ​ ​ ​ ​ ​ ​ ​ Borrowings, net ​ $ 1,211,210 ​ $ 1,187,856 Other liabilities, net ​ 143,939 ​ 168,243 Total liabilities ​ 1,355,149 ​ 1,356,099 Total equity ​ 1,206,908 ​ 1,428,954 Total liabilities and equity ​ $ 2,562,057 ​ $ 2,785,053 (1) Excludes all assets and liabilities related to The Marriott Wardman Park hotel as of September 30, 2020. On October 1, 2020, we transferred our interest in the related venture to our venture partner. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2020 2019 ​ 2020 2019 ​ (In thousands) Combined income statement information: (1) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total revenue ​ $ 47,235 ​ $ 65,110 ​ $ 162,128 ​ $ 199,897 Operating income (loss) (2) ​ ​ 1,296 ​ ​ 10,925 ​ (24,418) ​ 21,034 Net loss (2) ​ ​ (6,265) ​ ​ (3,602) ​ (60,331) ​ (20,289) (1) Excludes information related to the venture that owns The Marriott Wardman Park hotel for the three months ended September 30, 2020 as we suspended equity loss recognition for the venture after June 30, 2020. On October 1, 2020, we transferred our interest in the related venture to our venture partner. (2) Includes the loss from the sale of Woodglen of $16.4 million recognized by our unconsolidated real estate venture with Landmark during the nine months ended September 30, 2020.

Other Assets, Net (Tables)

Other Assets, Net (Tables)	9 Months Ended
	Sep. 30, 2020
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Summary of Other Assets, Net	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2020 December 31, 2019 ​ ​ (In thousands) Deferred leasing costs, net ​ $ 119,636 ​ $ 126,016 Lease intangible assets, net ​ 17,148 ​ 23,644 Management and leasing contracts, net ​ ​ 26,989 ​ ​ 31,515 Other identified intangible assets, net ​ 17,277 ​ 17,105 Operating lease right-of-use assets, net ​ 6,286 ​ 19,865 Finance lease right-of-use assets, net (1) ​ ​ 42,103 ​ ​ — Prepaid expenses ​ 20,372 ​ 12,556 Deferred financing costs on credit facility, net ​ 7,075 ​ 3,071 Deposits (2) ​ 28,410 ​ 3,210 Other ​ 16,718 ​ 16,705 Total other assets, net ​ $ 302,014 ​ $ 253,687 (1) Related to an amendment of the ground lease for 1730 M Street executed during the nine months ended September 30, 2020. The amendment extended the expiration date of the lease from April 2061 to December 2118, and resulted in its reclassification from an operating to a finance lease. (2) Includes deposits totaling $25.3 million with the Federal Communications Commission in connection with the acquisition of wireless spectrum licenses.

Debt (Tables)

Debt (Tables)	9 Months Ended
	Sep. 30, 2020
Mortgages Payable
Debt Instrument [Line Items]
Summary of Debt	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted Average ​ ​ ​ ​ ​ ​ ​ ​ ​ Effective ​ ​ ​ ​ Interest Rate (1) ​ September 30, 2020 December 31, 2019 ​ ​ ​ ​ ​ (In thousands) Variable rate (2) 2.18% ​ ​ $ 679,446 ​ $ 2,200 Fixed rate (3) 4.37% ​ ​ 1,021,825 ​ 1,125,648 Mortgages payable ​ ​ ​ ​ 1,701,271 ​ 1,127,848 Unamortized deferred financing costs and premium/ discount, net ​ ​ ​ ​ (10,548) ​ (2,071) Mortgages payable, net ​ ​ ​ ​ $ 1,690,723 ​ $ 1,125,777 (1) Weighted average effective interest rate as of September 30, 2020. (2) Includes variable rate mortgages payable with interest rate cap agreements. (3) Includes variable rate mortgages payable with interest rates fixed by interest rate swap agreements.
Credit Facility
Debt Instrument [Line Items]
Summary of Debt	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Effective ​ ​ ​ ​ Interest Rate (1) ​ September 30, 2020 December 31, 2019 ​ ​ ​ ​ ​ (In thousands) Revolving credit facility (2) (3) (4) 1.20% ​ ​ $ — ​ $ 200,000 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Tranche A-1 Term Loan (5) 2.59% ​ ​ $ 200,000 ​ $ 100,000 Tranche A-2 Term Loan (6) 2.49% ​ ​ 200,000 ​ 200,000 Unsecured term loans ​ ​ 400,000 ​ 300,000 Unamortized deferred financing costs, net ​ ​ (2,192) ​ (2,705) Unsecured term loans, net ​ ​ $ 397,808 ​ $ 297,295 (1) Effective interest rate as of September 30, 2020. (2) As of both September 30, 2020 and December 31, 2019, letters of credit with an aggregate face amount of $1.5 million were outstanding under our revolving credit facility. (3) As of September 30, 2020 and December 31, 2019, net deferred financing costs related to our revolving credit facility totaling $7.1 million and $3.1 million were included in "Other assets, net." (4) The interest rate for our revolving credit facility excludes a 0.15% facility fee. (5) As of September 30, 2020 and December 31, 2019, $200.0 million and $100.0 million of the outstanding balance was fixed by interest rate swap agreements. The interest rate swaps mature concurrently with the term loan and provide a weighted average interest rate of 1.39% . (6) As of September 30, 2020 and December 31, 2019, $200.0 million and $137.6 million of the outstanding balance was fixed by interest rate swap agreements. As of September 30, 2020, the interest rate swaps mature concurrently with the term loan and provide a weighted average interest rate of 1.34% .

Other Liabilities, Net (Tables)

Other Liabilities, Net (Tables)	9 Months Ended
	Sep. 30, 2020
Other Liabilities Disclosure [Abstract]
Composition of Other Liabilities, Net	​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2020 December 31, 2019 ​ ​ (In thousands) Lease intangible liabilities, net ​ $ 10,753 ​ $ 12,324 Lease assumption liabilities ​ 11,683 ​ 17,589 Lease incentive liabilities ​ 15,408 ​ 20,854 Liabilities related to operating lease right-of-use assets ​ 11,204 ​ 28,476 Liabilities related to finance lease right-of-use assets (1) ​ 40,049 ​ — Prepaid rent ​ 25,734 ​ 23,612 Security deposits ​ 14,431 ​ 16,348 Environmental liabilities ​ 17,898 ​ 17,898 Net deferred tax liability ​ 3,179 ​ 5,542 Dividends payable ​ — ​ 34,012 Derivative agreements, at fair value ​ 49,236 ​ 17,440 Other ​ 16,919 ​ 11,947 Total other liabilities, net ​ $ 216,494 ​ $ 206,042 (1) Related to an amendment of the ground lease for 1730 M Street executed during the nine months ended September 30, 2020. The amendment extended the expiration date of the lease from April 2061 to December 2118, and resulted in its reclassification from an operating to a finance lease.

Redeemable Noncontrolling Int_2

Redeemable Noncontrolling Interests (Tables)	9 Months Ended
	Sep. 30, 2020
Noncontrolling Interest [Abstract]
Redeemable Noncontrolling Interests	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ ​ 2020 ​ 2019 ​ ​ ​ ​ ​ Consolidated ​ ​ ​ ​ ​ ​ ​ Consolidated ​ ​ ​ ​ ​ JBG ​ Real Estate ​ ​ ​ ​ JBG ​ Real Estate ​ ​ ​ ​ SMITH LP Venture Total SMITH LP Venture Total ​ (In thousands) Balance as of the beginning of the period ​ $ 493,067 ​ $ 6,016 ​ $ 499,083 ​ $ 568,242 ​ $ 5,986 ​ $ 574,228 OP Unit redemptions ​ (4,796) ​ — ​ (4,796) ​ — ​ — ​ — Net income (loss) attributable to redeemable noncontrolling interests ​ (2,176) ​ (36) ​ (2,212) ​ 1,172 ​ — ​ 1,172 Other comprehensive income (loss) ​ 309 ​ — ​ 309 ​ (803) ​ — ​ (803) Distributions ​ (3,723) ​ — ​ (3,723) ​ (3,831) ​ — ​ (3,831) Share-based compensation expense ​ 14,496 ​ — ​ 14,496 ​ 14,320 ​ — ​ 14,320 Adjustment to redemption value ​ (14,012) ​ 1,776 ​ (12,236) ​ 1,446 ​ — ​ 1,446 Balance as of the end of the period ​ $ 483,165 ​ $ 7,756 ​ $ 490,921 ​ $ 580,546 ​ $ 5,986 ​ $ 586,532 ​ ​ Nine Months Ended September 30, ​ ​ 2020 ​ 2019 ​ ​ ​ ​ ​ Consolidated ​ ​ ​ ​ ​ ​ ​ Consolidated ​ ​ ​ ​ ​ JBG ​ Real Estate ​ ​ ​ ​ JBG ​ Real Estate ​ ​ ​ ​ SMITH LP Venture Total SMITH LP Venture Total ​ (In thousands) Balance as of the beginning of the period ​ $ 606,699 ​ $ 6,059 ​ $ 612,758 ​ $ 552,159 ​ $ 5,981 ​ $ 558,140 OP Unit redemptions ​ (40,674) ​ — ​ (40,674) ​ (57,318) ​ — ​ (57,318) LTIP Units issued in lieu of cash bonuses (1) ​ 4,066 ​ — ​ 4,066 ​ 3,954 ​ — ​ 3,954 Net income (loss) attributable to redeemable noncontrolling interests ​ (366) ​ (79) ​ (445) ​ 4,266 ​ 5 ​ 4,271 Other comprehensive income (loss) ​ (3,446) ​ — ​ (3,446) ​ (3,689) ​ — ​ (3,689) Distributions ​ (7,505) ​ — ​ (7,505) ​ (7,670) ​ — ​ (7,670) Share-based compensation expense ​ 51,742 ​ — ​ 51,742 ​ 45,937 ​ — ​ 45,937 Adjustment to redemption value ​ (127,351) ​ 1,776 ​ (125,575) ​ 42,907 ​ — ​ 42,907 Balance as of the end of the period ​ $ 483,165 ​ $ 7,756 ​ $ 490,921 ​ $ 580,546 ​ $ 5,986 ​ $ 586,532 (1) See Note 11 for additional information.

Property Rental Revenue (Tables

Property Rental Revenue (Tables)	9 Months Ended
	Sep. 30, 2020
Property Rentals Revenue [Abstract]
Property Rental Revenue	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2020 2019 ​ 2020 2019 ​ ​ (In thousands) Fixed ​ $ 109,321 ​ $ 114,538 ​ $ 326,866 ​ $ 342,268 Variable ​ ​ 9,359 ​ ​ 9,425 ​ ​ 27,653 ​ ​ 23,434 Property rental revenue ​ $ 118,680 ​ $ 123,963 ​ $ 354,519 ​ $ 365,702

Share-Based Payments (Tables)

Share-Based Payments (Tables)	9 Months Ended
	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Summary of Share-Based Compensation Expense	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2020 2019 ​ 2020 2019 ​ (In thousands) Time-Based LTIP Units ​ $ 3,364 ​ $ 2,755 ​ $ 11,003 ​ $ 8,529 Performance-Based LTIP Units ​ 3,999 ​ 2,016 ​ 14,207 ​ 6,205 LTIP Units ​ — ​ — ​ 1,100 ​ 1,000 Other equity awards (1) ​ 1,690 ​ 1,403 ​ 4,829 ​ 3,443 Share-based compensation expense - other ​ 9,053 ​ 6,174 ​ 31,139 ​ 19,177 Formation Awards ​ 875 ​ 1,227 ​ 3,473 ​ 4,116 OP Units (2) ​ 4,780 ​ 6,747 ​ 17,398 ​ 21,491 LTIP Units (2) ​ 95 ​ 117 ​ 310 ​ 340 Special Performance-Based LTIP Units (3) ​ 657 ​ 654 ​ 2,015 ​ 1,938 Special Time-Based LTIP Units (3) ​ 726 ​ 804 ​ 2,236 ​ 2,318 Share-based compensation related to Formation Transaction and special equity awards (4) ​ 7,133 ​ 9,549 ​ 25,432 ​ 30,203 Total share-based compensation expense ​ 16,186 ​ 15,723 ​ 56,571 ​ 49,380 Less amount capitalized ​ (1,177) ​ (406) ​ (3,388) ​ (1,948) Share-based compensation expense ​ $ 15,009 ​ $ 15,317 ​ $ 53,183 ​ $ 47,432 (1) Primarily comprising compensation expense for certain executives who have elected to receive all or a portion of any cash bonus that may be paid in the subsequent year related to past service in the form of fully vested LTIP Units and related to our ESPP. (2) Represents share-based compensation expense for LTIP Units and OP Units issued in the Formation Transaction, which are subject to post-Combination employment obligations. (3) Represents equity awards issued related to our successful pursuit of Amazon's additional headquarters in National Landing. (4) Included in "General and administrative expense: Share-based compensation related to Formation Transaction and special equity awards" in the accompanying statements of operations.
LTIP Units and Time-Based LTIP Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Summary of of the significant assumptions of awards	​ ​ ​ ​ Expected volatility 18.0% to 29.0% Risk-free interest rate 0.3% to 1.5% Post-grant restriction periods 2 to 3 years ​
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Summary of of the significant assumptions of awards	​ ​ ​ ​ Expected volatility 15.0% Dividend yield 2.3% Risk-free interest rate 1.3%
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Summary of of the significant assumptions of awards	​ ​ ​ ​ Expected volatility 13.0% Dividend yield 1.1% Risk-free interest rate 1.7% Expected life ​ 6 months

Transaction and Other Costs (Ta

Transaction and Other Costs (Tables)	9 Months Ended
	Sep. 30, 2020
Other Income and Expenses [Abstract]
Schedule of transaction and other costs	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2020 2019 ​ 2020 2019 ​ (In thousands) Demolition costs (1) ​ $ 179 ​ $ 503 ​ $ 179 ​ $ 4,693 Integration and severance costs ​ 406 ​ 1,021 ​ 3,066 ​ 4,274 Completed, potential and pursued transaction expenses ​ 260 ​ 535 ​ 281 ​ 961 Other (2) ​ — ​ — ​ 4,000 ​ — Transaction and other costs ​ $ 845 ​ $ 2,059 ​ $ 7,526 ​ $ 9,928 (1) Related to 223 23 rd Street and 2300 Crystal Drive for the three and nine months ended September 30, 2020. Related to 1900 Crystal Drive for the three and nine months ended September 30, 2019. (2) Represents a charitable commitment to the Washington Housing Conservancy, a non-profit that acquires and owns affordable workforce housing in the Washington D.C. metropolitan region.

Interest Expense (Tables)

Interest Expense (Tables)	9 Months Ended
	Sep. 30, 2020
Interest Expense [Abstract]
Schedule of Interest Expense	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2020 2019 ​ 2020 2019 ​ (In thousands) Interest expense before capitalized interest ​ $ 18,274 ​ $ 17,911 ​ $ 52,751 ​ $ 60,758 Amortization of deferred financing costs ​ 857 ​ 698 ​ 2,255 ​ 2,576 Interest expense related to finance lease right-of-use assets ​ ​ 464 ​ ​ 230 ​ ​ 1,026 ​ ​ 691 Net unrealized loss on derivative financial instruments not designated as cash flow hedges ​ 202 ​ 2 ​ 173 ​ 50 Capitalized interest ​ (2,912) ​ (8,258) ​ (11,545) ​ (23,211) Interest expense ​ $ 16,885 ​ $ 10,583 ​ $ 44,660 ​ $ 40,864

Shareholders' Equity and Earn_2

Shareholders' Equity and Earnings Per Common Share (Tables)	9 Months Ended
	Sep. 30, 2020
Shareholders' Equity and Earnings Per Common Share
Schedule of basic and diluted earnings per common share to net income	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ ​ 2020 2019 ​ 2020 2019 ​ ​ (In thousands, except per share amounts) Net income (loss) ​ $ (25,005) ​ $ 10,532 ​ $ (17,093) ​ $ 35,452 Net (income) loss attributable to redeemable noncontrolling interests ​ ​ 2,212 ​ (1,172) ​ 445 ​ (4,271) Net income (loss) attributable to common shareholders ​ ​ (22,793) ​ ​ 9,360 ​ ​ (16,648) ​ ​ 31,181 Distributions to participating securities ​ ​ (822) ​ ​ (679) ​ (1,729) ​ (1,674) Net income (loss) available to common shareholders — basic and diluted ​ $ (23,615) ​ $ 8,681 ​ $ (18,377) ​ $ 29,507 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted average number of common shares outstanding — basic and diluted ​ ​ 133,620 ​ ​ 134,127 ​ 133,924 ​ 129,527 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Earnings (loss) per common share: ​ ​ ​ ​ ​ ​ ​ ​ Basic ​ $ (0.18) ​ $ 0.06 ​ $ (0.14) ​ $ 0.23 Diluted ​ $ (0.18) ​ $ 0.06 ​ $ (0.14) ​ $ 0.23

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2020
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements ​ Total Level 1 Level 2 Level 3 ​ ​ (In thousands) September 30, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivative financial instruments designated as cash flow hedges: ​ ​ ​ ​ Classified as liabilities in "Other liabilities, net" ​ $ 49,236 ​ — ​ $ 49,236 ​ — Derivative financial instruments not designated as cash flow hedges: ​ ​ ​ ​ Classified as assets in "Other assets, net" ​ 47 ​ — ​ 47 ​ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ ​ Derivative financial instruments designated as cash flow hedges: ​ ​ ​ ​ Classified as liabilities in "Other liabilities, net" ​ $ 17,440 ​ — ​ $ 17,440 ​ —
Schedule of Financial Instruments and Liabilities as Reflected on Balance Sheet	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2020 ​ December 31, 2019 ​ Carrying ​ Carrying ​ ​ ​ Amount (1) ​ Fair Value ​ Amount (1) ​ Fair Value ​ (In thousands) Financial liabilities: ​ ​ ​ ​ Mortgages payable ​ $ 1,701,271 ​ $ 1,699,355 ​ $ 1,127,848 ​ $ 1,162,890 Revolving credit facility ​ — ​ — ​ 200,000 ​ 200,177 Unsecured term loans ​ 400,000 ​ 389,493 ​ 300,000 ​ 300,607 (1) The carrying amount consists of principal only.

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2020
Segment Reporting [Abstract]
Schedule of components of revenue from third-party real estate services business	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2020 2019 ​ 2020 2019 ​ (In thousands) Property management fees ​ $ 4,694 ​ $ 5,758 ​ $ 15,453 ​ $ 16,873 Asset management fees ​ 2,301 ​ 3,577 ​ 7,400 ​ 10,612 Development fees ​ 2,614 ​ 6,783 ​ 8,474 ​ 10,912 Leasing fees ​ 1,086 ​ 2,033 ​ 3,627 ​ 5,331 Construction management fees ​ 584 ​ 370 ​ 2,057 ​ 1,469 Other service revenue ​ 2,000 ​ 1,005 ​ 5,452 ​ 3,626 Third-party real estate services revenue, excluding reimbursements ​ 13,279 ​ 19,526 ​ 42,463 ​ 48,823 Reimbursements revenue (1) ​ 13,708 ​ 15,061 ​ 41,407 ​ 42,942 Third-party real estate services revenue, including reimbursements ​ ​ 26,987 ​ ​ 34,587 ​ ​ 83,870 ​ ​ 91,765 Third-party real estate services expenses ​ ​ 28,207 ​ ​ 29,809 ​ ​ 86,260 ​ ​ 86,585 Third-party real estate services revenue less expenses ​ $ (1,220) ​ $ 4,778 ​ $ (2,390) ​ $ 5,180 (1) Represents reimbursement of expenses incurred by us on behalf of third parties, including allocated payroll costs and amounts paid to third-party contractors for construction management projects.
Segment information	The following is the reconciliation of net income (loss) attributable to common shareholders to consolidated NOI: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2020 2019 ​ 2020 2019 ​ (In thousands) Net income (loss) attributable to common shareholders ​ $ (22,793) ​ $ 9,360 ​ $ (16,648) ​ $ 31,181 Add: ​ ​ ​ ​ Depreciation and amortization expense ​ 56,481 ​ 46,862 ​ 157,586 ​ 141,576 General and administrative expense: ​ ​ ​ ​ Corporate and other ​ 11,086 ​ 11,015 ​ 37,478 ​ 34,888 Third-party real estate services ​ 28,207 ​ 29,809 ​ 86,260 ​ 86,585 Share-based compensation related to Formation Transaction and special equity awards ​ 7,133 ​ 9,549 ​ 25,432 ​ 30,203 Transaction and other costs ​ 845 ​ 2,059 ​ 7,526 ​ 9,928 Interest expense ​ 16,885 ​ 10,583 ​ 44,660 ​ 40,864 Loss on extinguishment of debt ​ — ​ — ​ 33 ​ 1,889 Income tax expense (benefit) ​ (488) ​ 432 ​ (3,721) ​ (689) Net income (loss) attributable to redeemable noncontrolling interests ​ (2,212) ​ 1,172 ​ (445) ​ 4,271 Less: ​ ​ ​ ​ Third-party real estate services, including reimbursements revenue ​ 26,987 ​ 34,587 ​ 83,870 ​ 91,765 Other revenue (1) ​ 2,292 ​ 2,196 ​ 5,438 ​ 5,951 Income (loss) from unconsolidated real estate ventures, net ​ (965) ​ (1,144) ​ (17,142) ​ 647 Interest and other income (loss), net ​ — ​ (640) ​ 1,021 ​ 2,363 Gain on sale of real estate ​ — ​ 8,088 ​ 59,477 ​ 47,121 Consolidated NOI ​ $ 66,830 ​ $ 77,754 ​ $ 205,497 ​ $ 232,849 (1) Excludes parking revenue of $3.1 million and $10.3 million for the three and nine months ended September 30, 2020, and $6.3 million and $19.5 million for the three and nine months ended September 30, 2019. The following is a summary of NOI by segment. Items classified in the Other column include future development assets, corporate entities and the elimination of intersegment activity. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, 2020 ​ Commercial Multifamily Other Total ​ (In thousands) Property rental revenue ​ $ 90,050 ​ $ 30,452 ​ $ (1,822) ​ $ 118,680 Other property revenue ​ 3,002 ​ 74 ​ — ​ 3,076 Total property revenue ​ 93,052 ​ 30,526 ​ (1,822) ​ 121,756 Property expense: ​ ​ ​ ​ ​ ​ ​ Property operating ​ 26,701 ​ 13,226 ​ (2,355) ​ 37,572 Real estate taxes ​ 12,136 ​ 4,656 ​ 562 ​ 17,354 Total property expense ​ 38,837 ​ 17,882 ​ (1,793) ​ 54,926 Consolidated NOI ​ $ 54,215 ​ $ 12,644 ​ $ (29) ​ $ 66,830 ​ ​ Three Months Ended September 30, 2019 ​ Commercial Multifamily Other Total ​ (In thousands) Property rental revenue ​ $ 94,678 ​ $ 28,946 ​ $ 339 ​ $ 123,963 Other property revenue ​ 6,237 ​ 94 ​ — ​ 6,331 Total property revenue ​ 100,915 ​ 29,040 ​ 339 ​ 130,294 Property expense: ​ ​ ​ ​ ​ Property operating ​ 27,200 ​ 9,490 ​ (890) ​ 35,800 Real estate taxes ​ 12,004 ​ 3,552 ​ 1,184 ​ 16,740 Total property expense ​ 39,204 ​ 13,042 ​ 294 ​ 52,540 Consolidated NOI ​ $ 61,711 ​ $ 15,998 ​ $ 45 ​ $ 77,754 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, 2020 ​ Commercial Multifamily Other Total ​ (In thousands) Property rental revenue ​ $ 266,823 ​ $ 94,873 ​ $ (7,177) ​ $ 354,519 Other property revenue ​ 10,018 ​ 249 ​ — ​ 10,267 Total property revenue ​ 276,841 ​ 95,122 ​ (7,177) ​ 364,786 Property expense: ​ ​ ​ ​ ​ Property operating ​ 78,645 ​ 34,238 ​ (7,016) ​ 105,867 Real estate taxes ​ 36,532 ​ 14,088 ​ 2,802 ​ 53,422 Total property expense ​ 115,177 ​ 48,326 ​ (4,214) ​ 159,289 Consolidated NOI ​ $ 161,664 ​ $ 46,796 ​ $ (2,963) ​ $ 205,497 ​ ​ Nine Months Ended September 30, 2019 ​ Commercial Multifamily Other Total ​ ​ (In thousands) Property rental revenue ​ $ 285,551 ​ $ 86,069 ​ $ (5,918) ​ $ 365,702 Other property revenue ​ 19,212 ​ 263 ​ — ​ 19,475 Total property revenue ​ 304,763 ​ 86,332 ​ (5,918) ​ 385,177 Property expense: ​ ​ ​ ​ Property operating ​ 84,089 ​ 25,662 ​ (9,664) ​ 100,087 Real estate taxes ​ 37,257 ​ 11,243 ​ 3,741 ​ 52,241 Total property expense ​ 121,346 ​ 36,905 ​ (5,923) ​ 152,328 Consolidated NOI ​ $ 183,417 ​ $ 49,427 ​ $ 5 ​ $ 232,849 ​ The following is a summary of certain balance sheet data by segment: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial Multifamily Other Total ​ ​ (In thousands) September 30, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Real estate, at cost ​ $ 3,506,113 ​ $ 2,034,045 ​ $ 400,497 ​ $ 5,940,655 Investments in unconsolidated real estate ventures ​ 330,111 ​ 108,110 ​ 24,805 ​ 463,026 Total assets (1) ​ 3,473,426 ​ 1,798,714 ​ 1,005,184 ​ 6,277,324 December 31, 2019 ​ ​ ​ ​ Real estate, at cost ​ $ 3,415,294 ​ $ 1,998,297 ​ $ 361,928 ​ $ 5,775,519 Investments in unconsolidated real estate ventures ​ 396,199 ​ 107,882 ​ 38,945 ​ 543,026 Total assets (1) ​ 3,361,122 ​ 1,682,872 ​ 942,257 ​ 5,986,251 (1) Includes assets held for sale. See Note 3 for additional information.

Organization and Basis of Pre_3

Organization and Basis of Presentation - Narrative (Details)	Sep. 30, 2020ft²propertybuilding
Real Estate Properties [Line Items]
Number of Real Estate Properties	64
Under-construction assets
Real Estate Properties [Line Items]
Number of Real Estate Properties	2
Near-term Development
Real Estate Properties [Line Items]
Number of Real Estate Properties	10
Area of real estate property (in square feet) | ft²	5,600,000
Future Development
Real Estate Properties [Line Items]
Number of Real Estate Properties	28
Area of real estate property (in square feet) | ft²	14,200,000
Commercial Real Estate
Real Estate Properties [Line Items]
Number of Real Estate Properties	43
Area of real estate property (in square feet) | ft²	13,300,000
Multifamily
Real Estate Properties [Line Items]
Number of Real Estate Properties	21
Number of Units in Real Estate Property | building	7,800
Multifamily | Under-construction assets
Real Estate Properties [Line Items]
Number of Real Estate Properties	1
Number of Units in Real Estate Property | building	322
Wholly Owned Properties | Future Development
Real Estate Properties [Line Items]
Area of real estate property (in square feet) | ft²	11,500,000
Wholly Owned Properties | Commercial Real Estate
Real Estate Properties [Line Items]
Area of real estate property (in square feet) | ft²	11,200,000
Wholly Owned Properties | Commercial Real Estate | Under-construction assets
Real Estate Properties [Line Items]
Number of Real Estate Properties	1
Area of real estate property (in square feet) | ft²	274,000
Wholly Owned Properties | Multifamily
Real Estate Properties [Line Items]
Number of Units in Real Estate Property | building	5,999
Wholly Owned Properties | Multifamily | Under-construction assets
Real Estate Properties [Line Items]
Number of Units in Real Estate Property | ft²	161
JBG Smith, LP
Real Estate Properties [Line Items]
Ownership interest by parent	90.40%

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Sep. 30, 2020	Dec. 31, 2019
Lessor, Lease, Description [Line Items]
Tenant revenue (as a percent)				7.00%
Lease deferral requests granted	$ 1,200,000		$ 2,400,000
Credit losses against billed rent receivables	3,200,000		7,900,000
Credit losses against deferred (straight-line) rent receivables	$ 935,000		$ 4,500,000
Reserve against receivable from a parking operator		$ 2,400,000
Pacific Life Insurance Company | The Marriott Wardman Park hotel
Lessor, Lease, Description [Line Items]
Impairment charge		$ 6,500,000

Disposition and Assets Held f_3

Disposition and Assets Held for Sale (Details) $ in Thousands	Jan. 15, 2020USD ($)ft²	Jun. 30, 2020USD ($)	Sep. 30, 2020USD ($)ft²	Sep. 30, 2019USD ($)	Sep. 30, 2020USD ($)ft²	Sep. 30, 2019USD ($)	Dec. 31, 2019USD ($)ft²	Mar. 31, 2019USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash proceeds from sale					$ 154,493	$ 157,810
Gain on sale of real estate				$ 8,088	59,477	47,121
Loss recognized for sale			$ 965	$ 1,144	17,142	$ (647)
Assets held for sale			$ 74,089		$ 74,089		$ 168,412
Arlington, Virginia
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Area of real estate property (in square feet) | ft²							4,230
Assets held for sale							$ 168,412
Arlington, Virginia | Metropolitan Park
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Area of real estate property (in square feet) | ft²	2,150						2,150
Gross sales price	$ 154,952
Cash proceeds from sale	154,493
Gain on sale of real estate	$ 59,477
Assets held for sale							$ 94,517
Arlington, Virginia | Pen Place - Land Parcel
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Area of real estate property (in square feet) | ft²			2,080		2,080		2,080
Gross sales price								$ 149,900
Assets held for sale			$ 74,089		$ 74,089		$ 73,895
Woodglen | Landmark
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash proceeds from sale		$ 17,800
Loss recognized for sale		$ 3,000			$ 3,000

Investments in Unconsolidated_3

Investments in Unconsolidated Real Estate Ventures - Summary of Composition of Investments (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended	9 Months Ended
	Apr. 30, 2020	Jun. 30, 2020	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Schedule of Equity Method Investments [Line Items]
Total investments in unconsolidated real estate ventures			$ 463,026		$ 543,026
Distributions of capital from unconsolidated real estate ventures			$ 70,818	$ 7,557
Prudential Global Investment Management (PGIM)
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage			50.00%
Total investments in unconsolidated real estate ventures			$ 217,398		215,624
Landmark
Schedule of Equity Method Investments [Line Items]
Total investments in unconsolidated real estate ventures			$ 68,331		77,944
Landmark | Minimum
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage			1.80%
Landmark | Maximum
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage			49.00%
CBREI Venture
Schedule of Equity Method Investments [Line Items]
Total investments in unconsolidated real estate ventures			$ 65,598		68,405
CBREI Venture | Minimum
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage			5.00%
CBREI Venture | Maximum
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage			64.00%
Canadian Pension Plan Investment Board (CPPIB)
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage			55.00%
Total investments in unconsolidated real estate ventures			$ 48,041		109,911
Canadian Pension Plan Investment Board (CPPIB) | 1900 N Street
Schedule of Equity Method Investments [Line Items]
Distributions of capital from unconsolidated real estate ventures		$ 70,800
Canadian Pension Plan Investment Board (CPPIB) | 1900 N Street | Mortgages Payable
Schedule of Equity Method Investments [Line Items]
Maximum borrowing capacity	$ 160,000
Proceeds from loan	134,500
Remaining borrowing capacity	$ 25,500
Berkshire Group
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage			50.00%
Total investments in unconsolidated real estate ventures			$ 49,329		46,391
Brandywine Realty Trust
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage			30.00%
Total investments in unconsolidated real estate ventures			$ 13,769		13,830
Pacific Life Insurance Company
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage			20.00%
Total investments in unconsolidated real estate ventures		0	$ 0		10,385
Pacific Life Insurance Company | The Marriott Wardman Park hotel
Schedule of Equity Method Investments [Line Items]
Impairment charge		$ 6,500
Other
Schedule of Equity Method Investments [Line Items]
Total investments in unconsolidated real estate ventures			$ 560		$ 536

Investments in Unconsolidated_4

Investments in Unconsolidated Real Estate Ventures - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Jun. 30, 2020	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Schedule of Equity Method Investments [Line Items]
Proceeds from sale of real estate				$ 154,493	$ 157,810
Loss recognized for sale		$ 965	$ 1,144	17,142	(647)
Landmark | Woodglen
Schedule of Equity Method Investments [Line Items]
Proceeds from sale of real estate	$ 17,800
Loss recognized for sale	$ 3,000			3,000
Repayments of Secured Debt				12,200
Investments in Unconsolidated Real Estate Ventures
Schedule of Equity Method Investments [Line Items]
Property Management Fee Revenue		$ 6,300	$ 7,200	$ 19,300	$ 21,000

Investments in Unconsolidated_5

Investments in Unconsolidated Real Estate Ventures - Summary of Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Schedule of Equity Method Investments
Variable rate, weighted average interest rate	2.34%
Variable rate	$ 773,872	$ 629,479
Fixed rate, weighted average interest rate	3.79%
Fixed rate	$ 444,775	561,236
Unconsolidated real estate ventures - mortgages payable	1,218,647	1,190,715
Unamortized deferred financing costs	(7,437)	(2,859)
Unconsolidated real estate ventures - mortgages payable, net	1,211,210	$ 1,187,856
The Marriott Wardman Park hotel
Schedule of Equity Method Investments
Unconsolidated real estate ventures - mortgages payable, net	$ 129,000

Investments in Unconsolidated_6

Investments in Unconsolidated Real Estate Ventures - Condensed Combined Financial Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Combined balance sheet information:
Real estate, net	$ 2,287,736		$ 2,287,736		$ 2,493,961
Other assets, net	274,321		274,321		291,092
Total assets	2,562,057		2,562,057		2,785,053
Borrowings, net	1,211,210		1,211,210		1,187,856
Other liabilities, net	143,939		143,939		168,243
Total liabilities	1,355,149		1,355,149		1,356,099
Total equity	1,206,908		1,206,908		1,428,954
Total liabilities and equity	2,562,057		2,562,057		$ 2,785,053
Combined income statement information:
Total revenue	47,235	$ 65,110	162,128	$ 199,897
Operating income	1,296	10,925	(24,418)	21,034
Net loss	$ (6,265)	$ (3,602)	(60,331)	$ (20,289)
Landmark | Woodglen
Combined income statement information:
Loss from sale			$ 16,400

Variable Interest Entities (Det

Variable Interest Entities (Details) $ in Millions	Sep. 30, 2020USD ($)property	Dec. 31, 2019USD ($)
Variable Interest Entity [Line Items]
Number of Real Estate Properties | property	64
JBG Smith, LP
Variable Interest Entity [Line Items]
Ownership interest by parent	90.40%
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Assets | $	$ 116	$ 242.9

Other Assets, Net (Details)

Other Assets, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Deferred leasing costs, net	$ 119,636	$ 126,016
Lease intangible assets, net	17,148	23,644
Management and leasing contracts, net	26,989	31,515
Other identified intangible assets, net	17,277	17,105
Operating lease right-of-use assets, net	6,286	19,865
Finance lease right-of-use assets (1)	42,103
Prepaid expenses	20,372	12,556
Deferred financing costs on credit facility, net	7,075	3,071
Deposits	28,410	3,210
Other	16,718	16,705
Total other assets, net	302,014	253,687
Deposit to acquire wireless spectrum licenses	$ 25,300	$ 25,300

Debt - Schedule of Mortgages Pa

Debt - Schedule of Mortgages Payable (Details) - Mortgages Payable - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Variable interest rate	2.18%
Variable rate amount	$ 679,446	$ 2,200
Fixed interest rate	4.37%
Fixed rate amount	$ 1,021,825	1,125,648
Mortgages payable	1,701,271	1,127,848
Unamortized deferred financing costs and premium/ discount, net	(10,548)	(2,071)
Long-term debt, net	$ 1,690,723	$ 1,125,777

Debt - Narrative (Details)

Debt - Narrative (Details) $ in Millions	9 Months Ended
	Sep. 30, 2020USD ($)loan	Dec. 31, 2019USD ($)
Mortgages Payable
Mortgages and Line of Credit Facility [Line Items]
Net carrying value of real estate collateralizing the mortgages payable	$ 2,000	$ 1,400
Mortgages Payable | Interest rate swaps and caps
Mortgages and Line of Credit Facility [Line Items]
Derivative, notional amount	1,300	$ 867.6
Credit Facility
Mortgages and Line of Credit Facility [Line Items]
Credit facility, maximum borrowing capacity	1,400
Credit Facility | Revolving Credit Facility
Mortgages and Line of Credit Facility [Line Items]
Credit facility, maximum borrowing capacity	1,000
Credit Facility | Tranche A-1 Term Loan
Mortgages and Line of Credit Facility [Line Items]
Credit facility, maximum borrowing capacity	200
Credit Facility | Tranche A-2 Term Loan
Mortgages and Line of Credit Facility [Line Items]
Credit facility, maximum borrowing capacity	200
RTC - West | Mortgages Payable
Mortgages and Line of Credit Facility [Line Items]
Increase in principal balance	$ 20.2
4747 Bethesda Avenue, The Bartlett, 1221 Van Street and 220 20th Street
Mortgages and Line of Credit Facility [Line Items]
Number of mortgage loans | loan	4
Principal amount	$ 560

Debt - Summary of Amounts Outst

Debt - Summary of Amounts Outstanding under the Credit Facility (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Line of Credit Facility [Line Items]
Debt Issuance Costs, Line of Credit Arrangements, Net	$ 7,075	$ 3,071
Credit Facility | Revolving Credit Facility
Line of Credit Facility [Line Items]
Interest rate	1.20%
Long-term debt, net		200,000
Letters of Credit Outstanding, Amount	$ 1,500	$ 1,500
Line of Credit Facility, Commitment Fee Percentage	0.15%	0.15%
Credit Facility | Revolving Credit Facility | Other Assets Net
Line of Credit Facility [Line Items]
Debt Issuance Costs, Line of Credit Arrangements, Net	$ 7,100	$ 3,100
Credit Facility | Tranche A-1 Term Loan
Line of Credit Facility [Line Items]
Interest rate	2.59%
Debt, gross	$ 200,000	100,000
Credit Facility | Tranche A-1 Term Loan | Interest rate swap
Line of Credit Facility [Line Items]
Derivative, Notional Amount	$ 200,000	100,000
Weighted average interest rate	1.39%
Credit Facility | Tranche A-2 Term Loan
Line of Credit Facility [Line Items]
Interest rate	2.49%
Debt, gross	$ 200,000	200,000
Credit Facility | Tranche A-2 Term Loan | Interest rate swap
Line of Credit Facility [Line Items]
Derivative, Notional Amount	$ 200,000	137,600
Weighted average interest rate	1.34%
Credit Facility | Tranche A-1 and A-2 Loans
Line of Credit Facility [Line Items]
Debt, gross	$ 400,000	300,000
Unamortized deferred financing costs, net	(2,192)	(2,705)
Long-term debt, net	$ 397,808	$ 297,295

Other Liabilities, Net (Details

Other Liabilities, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Other Liabilities Disclosure [Abstract]
Lease intangible liabilities, net	$ 10,753	$ 12,324
Lease assumption liabilities	11,683	17,589
Lease incentive liabilities	15,408	20,854
Liabilities related to operating lease right-of-use assets	11,204	28,476
Liabilities related to finance lease right-of-use assets	40,049
Prepaid rent	25,734	23,612
Security deposits	14,431	16,348
Environmental liabilities	17,898	17,898
Net deferred tax liability	3,179	5,542
Dividends payable		34,012
Derivative agreements, at fair value	49,236	17,440
Other	16,919	11,947
Total other liabilities, net	$ 216,494	$ 206,042

Redeemable Noncontrolling Int_3

Redeemable Noncontrolling Interests - Narrative (Details) - shares	1 Months Ended	9 Months Ended
	Oct. 31, 2020	Sep. 30, 2020	Sep. 30, 2019
Consolidated Real Estate Venture
Noncontrolling Interest [Line Items]
Ownership interest by parent, threshold for capital contributions to cease		97.00%
OP Units
Noncontrolling Interest [Line Items]
Conversion of common limited partnership units to common shares	26,538	1,100,000	1,700,000
JBG Smith, LP
Noncontrolling Interest [Line Items]
Ownership interest by parent		90.40%
JBG Smith, LP | OP Units
Noncontrolling Interest [Line Items]
Units outstanding		14,000,000
Ownership interest by parent		9.60%
Consolidated Real Estate Venture
Noncontrolling Interest [Line Items]
Ownership interest by parent		95.90%

Redeemable Noncontrolling Int_4

Redeemable Noncontrolling Interests - Summary of the Activity of Redeemable Noncontrolling Interests (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Temporary Equity
Balance as of the beginning of the period	$ 499,083	$ 574,228	$ 612,758	$ 558,140
OP Unit redemptions	(4,796)		(40,674)	(57,318)
LTIP Units issued in lieu of cash bonuses (1)			4,066	3,954
Net income (loss) attributable to redeemable noncontrolling interests	(2,212)	1,172	(445)	4,271
Other comprehensive income (loss)	309	(803)	(3,446)	(3,689)
Distributions	(3,723)	(3,831)	(7,505)	(7,670)
Share-based compensation expense	14,496	14,320	51,742	45,937
Adjustment to redemption value	(12,236)	1,446	(125,575)	42,907
Balance as of the end of the period	490,921	586,532	490,921	586,532
JBG Smith, LP
Temporary Equity
Balance as of the beginning of the period	493,067	568,242	606,699	552,159
OP Unit redemptions	(4,796)		(40,674)	(57,318)
LTIP Units issued in lieu of cash bonuses (1)			4,066	3,954
Net income (loss) attributable to redeemable noncontrolling interests	(2,176)	1,172	(366)	4,266
Other comprehensive income (loss)	309	(803)	(3,446)	(3,689)
Distributions	(3,723)	(3,831)	(7,505)	(7,670)
Share-based compensation expense	14,496	14,320	51,742	45,937
Adjustment to redemption value	(14,012)	1,446	(127,351)	42,907
Balance as of the end of the period	483,165	580,546	483,165	580,546
Consolidated Real Estate Venture
Temporary Equity
Balance as of the beginning of the period	6,016	5,986	6,059	5,981
Net income (loss) attributable to redeemable noncontrolling interests	(36)		(79)	5
Adjustment to redemption value	1,776		1,776
Balance as of the end of the period	$ 7,756	$ 5,986	$ 7,756	$ 5,986

Property Rental Revenue (Detail

Property Rental Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Property Rentals Revenue [Abstract]
Fixed	$ 109,321	$ 114,538	$ 326,866	$ 342,268
Variable	9,359	9,425	27,653	23,434
Property rental revenue	$ 118,680	$ 123,963	$ 354,519	$ 365,702

Share-Based Payments - LTIP and

Share-Based Payments - LTIP and Time-Based LTIP Units (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	9 Months Ended
	Apr. 30, 2020	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Compensation expense recognition period (in years)		1 year 10 months 24 days
Management | Time-Based Long-Term Incentive Partnership Units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Equity grants (in shares)		381,504
Weighted average grant-date fair value (in dollars per share)		$ 38.52
Vesting period		4 years
Vesting (as a percent)		25.00%
Compensation expense recognition period (in years)		4 years
Fair value of awards on grant date		$ 14.7
Management | LTIP Units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Equity grants (in shares)		90,094
Weighted average grant-date fair value (in dollars per share)		$ 40.13
Fair value of awards on grant date		$ 3.6
Trustees | LTIP Units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Equity grants (in shares)	54,607
Fair value of awards on grant date	$ 1.5
Minimum | LTIP Units and Time-Based LTIP Units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Expected volatility		18.00%
Risk-free interest rate		0.30%
Post-grant restriction periods		2 years
Maximum | LTIP Units and Time-Based LTIP Units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Expected volatility		29.00%
Risk-free interest rate		1.50%
Post-grant restriction periods		3 years

Share-Based Payments - Performa

Share-Based Payments - Performance-Based LTIP Units (Details) - USD ($) $ / shares in Units, $ in Millions	Aug. 01, 2017	Sep. 30, 2020	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense recognition period (in years)			1 year 10 months 24 days
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity grants (in shares)			593,100
Weighted average grant-date fair value (in dollars per share)			$ 18.67
Vesting period	3 years		3 years
Fair value of awards on grant date			$ 11.1
Compensation expense recognition period (in years)			4 years
Expected volatility			15.00%
Dividend yield			2.30%
Risk-free interest rate			1.30%
Performance Shares | Tranche One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting (as a percent)			50.00%
Performance Shares | Tranche Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting (as a percent)			50.00%
Performance Shares | If Positive Absolute Total Shareholder Return, Not Achieved
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years		3 years
Performance Shares | If Positive Absolute Total Shareholder Return, Not Achieved | Tranche One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting (as a percent)			50.00%
Units forfeited (as a percentage)		50.00%
Units forfeited		(289,765)
Performance Shares | If Positive Absolute Total Shareholder Return, Achieved
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			7 years
Performance Shares | If Positive Absolute Total Shareholder Return, Achieved | Tranche Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		7 years
Vesting (as a percent)		50.00%	50.00%

Share-Based Payments - ESPP (De

Share-Based Payments - ESPP (Details) - USD ($)	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense recognition period (in years)	1 year 10 months 24 days
Proceeds from common stock issued pursuant to ESPP	$ 887,000	$ 747,000
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares issued pursuant to Employee Share Purchase Plan ( in shares)	35,307
Proceeds from common stock issued pursuant to ESPP	$ 887,000
Expected volatility	13.00%
Dividend yield	1.10%
Risk-free interest rate	1.70%
Expected life	6 months

Share-Based Payments - Summary

Share-Based Payments - Summary of Share-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	$ 16,186	$ 15,723	$ 56,571	$ 49,380
Less amount capitalized	(1,177)	(406)	(3,388)	(1,948)
Share-based compensation expense	15,009	15,317	53,183	47,432
Total unrecognized compensation expense	59,700		$ 59,700
Compensation expense recognition period (in years)			1 year 10 months 24 days
Share Based Compensation - Other
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	9,053	6,174	$ 31,139	19,177
Time-Based Long-Term Incentive Partnership Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	3,364	2,755	11,003	8,529
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	3,999	2,016	$ 14,207	6,205
Compensation expense recognition period (in years)			4 years
LTIP Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense			$ 1,100	1,000
Other Equity Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	1,690	1,403	4,829	3,443
Share Based Compensation Related To Formation Transaction and Special Equity Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	7,133	9,549	25,432	30,203
Formation Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	875	1,227	3,473	4,116
OP Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	4,780	6,747	17,398	21,491
LTIP Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	95	117	310	340
Special Performance-Based LTIP Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	657	654	2,015	1,938
Special Time-Based LTIP Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	$ 726	$ 804	$ 2,236	$ 2,318

Transaction and Other Costs (De

Transaction and Other Costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Other Income and Expenses [Abstract]
Demolition Costs	$ 179	$ 503	$ 179	$ 4,693
Integration and severance costs	406	1,021	3,066	4,274
Completed, potential and pursued transaction expenses	260	535	281	961
Other			4,000
Transaction and other costs	$ 845	$ 2,059	$ 7,526	$ 9,928

Interest Expense (Details)

Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Interest Expense [Abstract]
Interest expense before capitalized interest	$ 18,274	$ 17,911	$ 52,751	$ 60,758
Amortization of deferred financing costs	857	698	2,255	2,576
Interest expense related to finance lease right-of-use assets	464	230	1,026	691
Net unrealized loss on derivative financial instruments not designated as cash flow hedges	202	2	173	50
Capitalized interest	(2,912)	(8,258)	(11,545)	(23,211)
Interest Expense	$ 16,885	$ 10,583	$ 44,660	$ 40,864

Shareholders' Equity and Earn_3

Shareholders' Equity and Earnings Per Common Share -Common Shares Repurchased (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Mar. 31, 2020
Shareholders' Equity and Earnings Per Common Share
Authorized value of shares for repurchase			$ 500
Repurchase and retired common shares	1.4	2.9
Repurchase and retired common shares, Value	$ 38.4	$ 79.6
Average purchase price	$ 26.64	$ 27.82

Shareholders' Equity and Earn_4

Shareholders' Equity and Earnings Per Common Share - Basic and Diluted Earnings (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Shareholders' Equity and Earnings Per Common Share
Net income (loss)	$ (25,005)	$ 10,532	$ (17,093)	$ 35,452
Net (income) loss attributable to redeemable noncontrolling interests	2,212	(1,172)	445	(4,271)
NET INCOME (LOSS) ATTRIBUTABLE TO COMMON SHAREHOLDERS	(22,793)	9,360	(16,648)	31,181
Distributions to participating securities	(822)	(679)	(1,729)	(1,674)
Net income (loss) available to common shareholders - basic	(23,615)	8,681	(18,377)	29,507
Net income (loss) available to common shareholders - diluted	$ (24,726)	$ 8,681	$ (19,488)	$ 29,507
Weighted average number of common shares outstanding - basic and diluted	133,620	134,127	133,924	129,527
Earnings (loss) per common share:
Earnings, (loss) Per Share, Basic	$ (0.18)	$ 0.06	$ (0.14)	$ 0.23
Earnings, (loss) Per Share, Diluted	$ (0.18)	$ 0.06	$ (0.14)	$ 0.23

Shareholders' Equity and Earn_5

Shareholders' Equity and Earnings Per Common Share - Antidilutive (Details) - shares shares in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Shareholders' Equity and Earnings Per Common Share
Antidilutive securities excluded from computation of earnings per share (in shares)	4.4	4.7	4.9	4.7

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Net unrealized loss on derivative designated as cash flow hedge	$ 49.1	$ 17.7
Loss expected to be reclassified into interest expense within the next 12 months	$ 17.5

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis (Details) - Interest rate swaps and caps - Recurring - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Other Assets Net | Not Designated as Hedging Instrument
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Classified as assets in Other assets, net	$ 47
Other Assets Net | Not Designated as Hedging Instrument | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Classified as assets in Other assets, net	47
Other Liabilities, Net | Designated as Hedging Instrument
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Classified as liabilities in Other liabilities, net	49,236	$ 17,440
Other Liabilities, Net | Designated as Hedging Instrument | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Classified as liabilities in Other liabilities, net	$ 49,236	$ 17,440

Fair Value Measurements - Finan

Fair Value Measurements - Financial Assets and Liabilities Not Measured at Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Mortgages Payable | Fair Value
Financial liabilities:
Financial liabilities	$ 1,699,355	$ 1,162,890
Mortgages Payable | Carrying Amount
Financial liabilities:
Financial liabilities	1,701,271	1,127,848
Revolving Credit Facility | Fair Value
Financial liabilities:
Financial liabilities		200,177
Revolving Credit Facility | Carrying Amount
Financial liabilities:
Financial liabilities		200,000
Tranche A-1 and A-2 Loans | Fair Value
Financial liabilities:
Financial liabilities	389,493	300,607
Tranche A-1 and A-2 Loans | Carrying Amount
Financial liabilities:
Financial liabilities	$ 400,000	$ 300,000

Segment Information - Narrative

Segment Information - Narrative (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2020USD ($)segment	Dec. 31, 2019USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment	3
Other assets, net	$ 302,014	$ 253,687
Third-Party Real Estate Services Segment
Segment Reporting Information [Line Items]
Other assets, net	$ 27,000	$ 31,500

Segment Information - Summary o

Segment Information - Summary of Third-party Asset Management and Real Estate Services (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Third-party real estate services revenue, excluding reimbursements	$ 13,279	$ 19,526	$ 42,463	$ 48,823
Reimbursements revenue	13,708	15,061	41,407	42,942
Third-party real estate services revenue, including reimbursements	26,987	34,587	83,870	91,765
Third-party real estate services expenses	28,207	29,809	86,260	86,585
Third-party real estate services revenue less expenses	(1,220)	4,778	(2,390)	5,180
Property management fees
Third-party real estate services revenue, excluding reimbursements	4,694	5,758	15,453	16,873
Asset management fees
Third-party real estate services revenue, excluding reimbursements	2,301	3,577	7,400	10,612
Leasing fees
Third-party real estate services revenue, excluding reimbursements	1,086	2,033	3,627	5,331
Development fees
Third-party real estate services revenue, excluding reimbursements	2,614	6,783	8,474	10,912
Construction management fees
Third-party real estate services revenue, excluding reimbursements	584	370	2,057	1,469
Other service revenue
Third-party real estate services revenue, excluding reimbursements	$ 2,000	$ 1,005	$ 5,452	$ 3,626

Segment Information - Schedule

Segment Information - Schedule of Reconciliation of Net Income Attributable to Parent (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Net income (loss) attributable to common shareholders	$ (22,793)	$ 9,360	$ (16,648)	$ 31,181
Depreciation and amortization expense	56,481	46,862	157,586	141,576
Corporate and other	11,086	11,015	37,478	34,888
Third-party real estate services	28,207	29,809	86,260	86,585
Share-based compensation related to Formation Transaction and special equity awards	7,133	9,549	25,432	30,203
Transaction and other costs	845	2,059	7,526	9,928
Interest expense	16,885	10,583	44,660	40,864
Loss on extinguishment of debt			33	1,889
Income tax expense (benefit)	(488)	432	(3,721)	(689)
Net income (loss) attributable to redeemable noncontrolling interests	(2,212)	1,172	(445)	4,271
Third-party real estate services, including reimbursements revenue	26,987	34,587	83,870	91,765
Other revenue	2,292	2,196	5,438	5,951
Income (loss) from unconsolidated real estate ventures, net	(965)	(1,144)	(17,142)	647
Interest and other income (loss), net		(640)	1,021	2,363
Gain on sale of real estate		8,088	59,477	47,121
Consolidated NOI	66,830	77,754	205,497	232,849
Parking
Segment Reporting Information [Line Items]
Revenue	$ 3,100	$ 6,300	$ 10,300	$ 19,500

Segment Information - Summary_2

Segment Information - Summary of NOI by Segment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Property rental revenue	$ 118,680	$ 123,963	$ 354,519	$ 365,702
Other property revenue	3,076	6,331	10,267	19,475
Total rental revenue	121,756	130,294	364,786	385,177
Property operating	37,572	35,800	105,867	100,087
Real estate taxes	17,354	16,740	53,422	52,241
Total property expense	54,926	52,540	159,289	152,328
Consolidated NOI	66,830	77,754	205,497	232,849
Operating Segments | Commercial Segment
Segment Reporting Information [Line Items]
Property rental revenue	90,050	94,678	266,823	285,551
Other property revenue	3,002	6,237	10,018	19,212
Total rental revenue	93,052	100,915	276,841	304,763
Property operating	26,701	27,200	78,645	84,089
Real estate taxes	12,136	12,004	36,532	37,257
Total property expense	38,837	39,204	115,177	121,346
Consolidated NOI	54,215	61,711	161,664	183,417
Operating Segments | Multifamily
Segment Reporting Information [Line Items]
Property rental revenue	30,452	28,946	94,873	86,069
Other property revenue	74	94	249	263
Total rental revenue	30,526	29,040	95,122	86,332
Property operating	13,226	9,490	34,238	25,662
Real estate taxes	4,656	3,552	14,088	11,243
Total property expense	17,882	13,042	48,326	36,905
Consolidated NOI	12,644	15,998	46,796	49,427
Other
Segment Reporting Information [Line Items]
Property rental revenue	(1,822)	339	(7,177)	(5,918)
Total rental revenue	(1,822)	339	(7,177)	(5,918)
Property operating	(2,355)	(890)	(7,016)	(9,664)
Real estate taxes	562	1,184	2,802	3,741
Total property expense	(1,793)	294	(4,214)	(5,923)
Consolidated NOI	$ (29)	$ 45	$ (2,963)	$ 5

Segment Information - Summary_3

Segment Information - Summary of Certain Balance Sheet Data by Segment (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Real estate, at cost	$ 5,940,655	$ 5,775,519
Investments in unconsolidated real estate ventures	463,026	543,026
Total assets (1)	6,277,324	5,986,251
Operating Segments | Commercial Segment
Segment Reporting Information [Line Items]
Real estate, at cost	3,506,113	3,415,294
Investments in unconsolidated real estate ventures	330,111	396,199
Total assets (1)	3,473,426	3,361,122
Operating Segments | Multifamily
Segment Reporting Information [Line Items]
Real estate, at cost	2,034,045	1,998,297
Investments in unconsolidated real estate ventures	108,110	107,882
Total assets (1)	1,798,714	1,682,872
Other
Segment Reporting Information [Line Items]
Real estate, at cost	400,497	361,928
Investments in unconsolidated real estate ventures	24,805	38,945
Total assets (1)	$ 1,005,184	$ 942,257

Commitments and Contingencies -

Commitments and Contingencies - Narrative (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Real Estate Properties [Line Items]
General liability insurance limit	$ 150,000
Property and rental value insurance coverage limit	1,500,000
Terrorist acts insurance coverage limit	2,000,000
Purchase obligation	34,000
Environmental liabilities included in Other liabilities, net	17,898	$ 17,898
Consolidated Properties
Real Estate Properties [Line Items]
Purchase obligation	20,200
Principal payment guarantees	8,300
Unconsolidated Properties
Real Estate Properties [Line Items]
Purchase obligation	13,800
Additional capital funding committed amount	56,900
Principal payment guarantees	$ 0
Minimum
Real Estate Properties [Line Items]
Commitment amortization period	1 year
Maximum
Real Estate Properties [Line Items]
Commitment amortization period	2 years

Transactions with Related Par_2

Transactions with Related Parties (Details) - Affiliated Entity - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Washington Housing Initiative
Related Party Transaction [Line Items]
Qualified Affordable Housing Project Investments, Total Capital Commitments	$ 112,000,000		$ 112,000,000
Qualified Affordable Housing Project Investments, Commitment	10,900,000		10,900,000
Supervisory Services of Properties | BMS
Related Party Transaction [Line Items]
Related party transaction amount	4,000,000	$ 5,500,000	12,600,000	$ 16,100,000
Fees from Legacy JBG Funds and Washington Housing Initiative | Legacy JBG Funds and Washington Housing Initiative
Related Party Transaction [Line Items]
Revenue from related parties	4,600,000	10,200,000	17,300,000	28,600,000
Accounts Receivable, Related Parties	8,100,000		8,100,000		$ 6,200,000
Office Rent | Unconsolidated Real Estate Venture
Related Party Transaction [Line Items]
Related party transaction amount	$ 403,000	$ 867,000	$ 4,100,000	$ 3,400,000

Subsequent Events (Details)

Subsequent Events (Details) - $ / shares	Oct. 29, 2020	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Subsequent Event [Line Items]
Common Stock, Dividends, Per Share, Declared		$ 0.225	$ 0.225	$ 0.45	$ 0.45
Subsequent Event [Member]
Subsequent Event [Line Items]
Common Stock, Dividends, Per Share, Declared	$ 0.225