JBG SMITH Properties (JBGS) 10-Q 5 Nov 19 2019 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2019	Oct. 31, 2019
Cover page.
Document Transition Report	false
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2019
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	4445 Willard Avenue
Entity Address, City or Town	Chevy Chase
Entity Address, State or Province	MD
Entity Address, Postal Zip Code	20815
City Area Code	240
Local Phone Number	333-3600
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
Title of 12(b) Security	Common Shares, par value $0.01 per share
Trading Symbol	JBGS
Security Exchange Name	NYSE
Entity Common Stock, Shares Outstanding		134,127,004
Entity Central Index Key	0001689796
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Address, Address Line Two	Suite 400

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Real estate, at cost:
Land and improvements	$ 1,283,043	$ 1,371,874
Buildings and improvements	3,824,467	3,722,930
Construction in progress, including land	763,080	697,930
Real estate, at cost	5,870,590	5,792,734
Less accumulated depreciation	(1,109,897)	(1,051,875)
Real estate, net	4,760,693	4,740,859
Cash and cash equivalents	230,147	260,553
Restricted cash	13,573	138,979
Tenant and other receivables, net	53,965	46,568
Deferred rent receivable, net	172,386	143,473
Investments in and advances to unconsolidated real estate ventures	320,920	322,878
Other assets, net	301,760	264,994
Assets held for sale	168,820	78,981
TOTAL ASSETS	6,022,264	5,997,285
Liabilities:
Mortgages payable, net	1,358,571	1,838,381
Unsecured term loans, net	297,124	297,129
Accounts payable and accrued expenses	160,031	130,960
Other liabilities, net	205,705	181,606
Liabilities related to assets held for sale	66	3,717
Total liabilities	2,021,497	2,451,793
Commitments and contingencies
Redeemable noncontrolling interests	586,532	558,140
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; 134,127 and 120,937 shares issued and outstanding as of September 30, 2019 and December 31, 2018	1,342	1,210
Additional paid-in capital	3,643,333	3,155,256
Accumulated deficit	(205,192)	(176,018)
Accumulated other comprehensive income (loss)	(25,578)	6,700
Total shareholders' equity of JBG SMITH Properties	3,413,905	2,987,148
Noncontrolling interests in consolidated subsidiaries	330	204
Total equity	3,414,235	2,987,352
TOTAL LIABILITIES, REDEEMABLE NONCONTROLLING INTERESTS AND EQUITY	$ 6,022,264	$ 5,997,285

Consolidated and Combined Balan

Consolidated and Combined Balance Sheets (Parenthetical) - USD ($)	Sep. 30, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Preferred shares, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred shares, shares authorized	200,000,000	200,000,000
Preferred shares, shares issued	0	0
Preferred shares, shares outstanding	0	0
Common shares, par value (in dollars per share)	$ 0.01	$ 0.01
Common shares, shares authorized	500,000,000	500,000,000
Common shares, shares issued	134,127,000	120,937,000
Common shares, shares outstanding	134,127,000	120,937,000
Commitments and Contingencies

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
REVENUE
Property rentals		$ 126,580		$ 384,399
Operating Lease, Lease Income	$ 123,963		$ 365,702
Third-party real estate services, including reimbursements	34,587	23,788	91,765	72,278
Other income	8,527	8,075	25,426	24,250
Total revenue	167,077	158,443	482,893	480,927
EXPENSES
Depreciation and amortization	46,862	46,603	141,576	143,880
Direct Costs of Leased and Rented Property or Equipment	35,800	38,381	100,087	108,003
Real estate taxes	16,740	16,905	52,241	54,024
General and administrative:
Corporate and other	11,015	8,201	34,888	25,218
Third-party real estate services	29,809	20,754	86,585	64,552
Share-based compensation related to Formation Transaction and special equity awards	9,549	8,387	30,203	26,912
Transaction and other costs	2,059	4,126	9,928	12,134
Total expenses	151,834	143,357	455,508	434,723
Income (loss) from unconsolidated real estate ventures, net	(1,144)	13,484	647	15,418
Interest and other income (loss), net	(640)	4,091	2,363	5,177
Interest expense	(10,583)	(18,979)	(40,864)	(56,263)
Gain on sale of real estate	8,088	11,938	47,121	45,789
Loss on extinguishment of debt	0	(79)	(1,889)	(4,536)
Reduction of gain on bargain purchase	0	0	0	(7,606)
Total other income (expense)	(4,279)	10,455	7,378	(2,021)
INCOME (LOSS) BEFORE INCOME TAX BENEFIT	10,964	25,541	34,763	44,183
Income tax (expense) benefit	(432)	841	689	1,436
NET INCOME (LOSS)	10,532	26,382	35,452	45,619
Net (income) loss attributable to redeemable noncontrolling interests	(1,172)	(3,552)	(4,271)	(6,532)
Net loss attributable to noncontrolling interests	0	0	0	127
NET INCOME (LOSS) ATTRIBUTABLE TO COMMON SHAREHOLDERS	$ 9,360	$ 22,830	$ 31,181	$ 39,214
EARNINGS (LOSS) PER COMMON SHARE:
Earnings Per Share, Basic	$ 0.06	$ 0.19	$ 0.23	$ 0.33
Earnings Per Share, Diluted	$ 0.06	$ 0.19	$ 0.23	$ 0.33
Weighted average number of common shares outstanding — basic and diluted	134,127	119,835	129,527	118,588
Weighted average number of common shares outstanding — diluted	134,127	119,835	129,527	118,588

Consolidated and Combined State

Consolidated and Combined Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
NET INCOME (LOSS)	$ 10,532	$ 26,382	$ 35,452	$ 45,619
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax	(7,014)	5,142	(33,966)	24,453
Other Comprehensive Income (Loss) [Abstract]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax	211	(24)	2,001	(1,473)
Other comprehensive income (loss)	7,225	(5,166)	35,967	(25,926)
COMPREHENSIVE INCOME (LOSS)	3,307	31,548	(515)	71,545
Net (income) loss attributable to redeemable noncontrolling interests	(1,172)	(3,552)	(4,271)	(6,532)
Other comprehensive (income) loss attributable to redeemable noncontrolling interests	803	(696)	3,689	(3,406)
Net loss attributable to noncontrolling interests	0	0	0	127
COMPREHENSIVE INCOME (LOSS) ATTRIBUTABLE TO JBG SMITH PROPERTIES	$ 2,938	$ 27,300	$ (1,097)	$ 61,734

Consolidated Statements of Equi

Consolidated Statements of Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Shares	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Income	Noncontrolling Interests in Consolidated Subsidiaries
Common Stock, Dividends, Per Share, Declared	$ 0.45
Balance at beginning of period at Dec. 31, 2017	$ 2,974,814	$ 1,180	$ 3,063,625	$ (95,809)	$ 1,612	$ 4,206
Balance at beginning of period (in shares) at Dec. 31, 2017		117,955
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to common shareholders and noncontrolling interests	39,087			39,214		(127)
Conversion of common limited partnership units to common shares	109,122	$ 30	109,092
Conversion of common limited partnership units to common shares		2,962
Dividends	(53,624)			(53,624)
Distributions to noncontrolling interests	(814)					(814)
Contributions from noncontrolling interests	250					250
Redeemable noncontrolling interests redemption value adjustment and other comprehensive (income) loss allocation	(24,752)		(21,346)		(3,406)
Other Comprehensive Income (Loss), Net of Tax	25,926				25,926
Other	(472)		(472)
Balance at end of period (in shares) at Sep. 30, 2018		120,917
Balance at end of period at Sep. 30, 2018	$ 3,069,537	$ 1,210	3,150,899	(110,219)	24,132	3,515
Common Stock, Dividends, Per Share, Declared	$ 0.225
Balance at beginning of period at Jun. 30, 2018	$ 2,953,666	$ 1,180	3,035,194	(105,962)	19,662	3,592
Balance at beginning of period (in shares) at Jun. 30, 2018		117,955
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to common shareholders and noncontrolling interests	22,830			22,830		0
Conversion of common limited partnership units to common shares	109,122	$ 30	109,092
Conversion of common limited partnership units to common shares		2,962
Dividends	(27,087)			(27,087)
Distributions to noncontrolling interests	(327)					(327)
Contributions from noncontrolling interests	250					250
Redeemable noncontrolling interests redemption value adjustment and other comprehensive (income) loss allocation	5,841		6,537		(696)
Other Comprehensive Income (Loss), Net of Tax	5,166				5,166
Other	76		76
Balance at end of period (in shares) at Sep. 30, 2018		120,917
Balance at end of period at Sep. 30, 2018	$ 3,069,537	$ 1,210	3,150,899	(110,219)	24,132	3,515
Common Stock, Dividends, Per Share, Declared	$ 0.45
Balance at beginning of period at Dec. 31, 2018	$ 2,987,352	$ 1,210	3,155,256	(176,018)	6,700	204
Balance at beginning of period (in shares) at Dec. 31, 2018	120,937	120,937
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to common shareholders and noncontrolling interests	$ 31,181			31,181
Common shares issued		11,500
Conversion of common limited partnership units to common shares	$ 57,318	$ 17	57,301
Stock Issued During Period, Shares, Employee Stock Purchase Plans	26
Stock Issued During Period, Value, Employee Stock Purchase Plan	$ 1,018		1,018
Conversion of common limited partnership units to common shares	(472,780)	$ (115)	(472,665)
Conversion of common limited partnership units to common shares		1,664
Dividends	(60,355)			(60,355)
Distributions to noncontrolling interests	(47)					(47)
Contributions from noncontrolling interests	173					173
Redeemable noncontrolling interests redemption value adjustment and other comprehensive (income) loss allocation	(39,218)		(42,907)		3,689
Other Comprehensive Income (Loss), Net of Tax	$ (35,967)				(35,967)
Balance at end of period (in shares) at Sep. 30, 2019	134,127	134,127
Balance at end of period at Sep. 30, 2019	$ 3,414,235	$ 1,342	3,643,333	(205,192)	(25,578)	330
Common Stock, Dividends, Per Share, Declared	$ 0.225
Balance at beginning of period at Jun. 30, 2019	$ 3,442,858	$ 1,342	3,644,699	(184,373)	(19,156)	346
Balance at beginning of period (in shares) at Jun. 30, 2019		134,127
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to common shareholders and noncontrolling interests	$ 9,360			9,360
Stock Issued During Period, Shares, Employee Stock Purchase Plans	0
Stock Issued During Period, Value, Employee Stock Purchase Plan	$ 80		80
Dividends	(30,179)			(30,179)
Distributions to noncontrolling interests	(16)					(16)
Redeemable noncontrolling interests redemption value adjustment and other comprehensive (income) loss allocation	(643)		(1,446)		803
Other Comprehensive Income (Loss), Net of Tax	$ (7,225)				(7,225)
Balance at end of period (in shares) at Sep. 30, 2019	134,127	134,127
Balance at end of period at Sep. 30, 2019	$ 3,414,235	$ 1,342	$ 3,643,333	$ (205,192)	$ (25,578)	$ 330

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
OPERATING ACTIVITIES:
Net income	$ 35,452,000	$ 45,619,000
Adjustments to reconcile net income to net cash provided by operating activities:
Share-based compensation expense	47,432,000	39,690,000
Depreciation and amortization, including amortization of debt issuance costs	144,868,000	146,958,000
Deferred rent	(29,164,000)	(7,880,000)
Income from unconsolidated real estate ventures, net	(647,000)	(15,418,000)
Amortization of above- and below-market lease intangibles, net	(486,000)	(58,000)
Amortization of lease incentives	4,344,000	3,646,000
Reduction of gain on bargain purchase	0	(7,606,000)
Loss on extinguishment of debt	1,889,000	4,536,000
Gain on sale of real estate	(47,121,000)	(45,789,000)
Net unrealized loss (gain) on derivative financial instruments not designated as cash flow hedges	50,000	(1,264,000)
Losses on operating lease receivables	1,281,000	2,591,000
Return on capital from unconsolidated real estate ventures	1,836,000	6,820,000
Other non-cash items	20,000	1,499,000
Changes in operating assets and liabilities:
Tenant and other receivables	(9,077,000)	2,167,000
Other assets, net	(13,858,000)	(18,637,000)
Accounts payable and accrued expenses	(17,171,000)	(23,875,000)
Other liabilities, net	(7,009,000)	(11,550,000)
Net cash provided by operating activities	112,639,000	136,661,000
INVESTING ACTIVITIES:
Development costs, construction in progress and real estate additions	(294,355,000)	(260,396,000)
Deposits for real estate acquisitions	(9,125,000)	0
Proceeds from sale of real estate	157,810,000	346,149,000
Acquisition of interests in unconsolidated real estate ventures, net of cash acquired	0	(386,000)
Distributions of capital from unconsolidated real estate ventures	7,557,000	2,240,000
Proceeds from Sale of Equity Method Investments	0	24,602,000
Investments in and advances to unconsolidated real estate ventures	(7,325,000)	(22,663,000)
Other	0	(665,000)
Net cash (used in) provided by investing activities	(145,438,000)	88,881,000
FINANCING ACTIVITIES:
Acquisition of ownership interest in consolidated real estate venture	0	(548,000)
Finance lease payments	(103,000)	(82,000)
Borrowings under mortgages payable	0	43,823,000
Borrowings under revolving credit facility	0	35,000,000
Borrowings under unsecured term loans	0	250,000,000
Repayments of mortgages payable	(482,810,000)	(267,285,000)
Repayments of revolving credit facility	0	150,751,000
Debt issuance costs	515,000	372,000
Proceeds from the issuance of common stock, net of issuance costs	473,527,000	0
Dividends paid to common shareholders	(99,654,000)	(80,166,000)
Distributions to redeemable noncontrolling interests	(13,564,000)	(13,320,000)
Contributions from noncontrolling interests	125,000	250,000
Distributions to noncontrolling interests	(19,000)	(439,000)
Net cash used in financing activities	(123,013,000)	(183,890,000)
Net (decrease) increase in cash and cash equivalents and restricted cash	(155,812,000)	41,652,000
Cash and cash equivalents and restricted cash as of the beginning of the period	399,532,000	338,557,000
Cash and cash equivalents and restricted cash as of the end of the period	243,720,000	380,209,000
CASH AND CASH EQUIVALENTS AND RESTRICTED CASH AS OF END OF THE PERIOD:
Cash and cash equivalents and restricted cash	399,532,000	338,557,000
SUPPLEMENTAL DISCLOSURE OF CASH FLOW AND NON-CASH INFORMATION:
Cash paid for interest (net of capitalized interest of $23,211 and $14,863 in 2019 and 2018)	38,563,000	48,835,000
Accrued capital expenditures included in accounts payable and accrued expenses	99,876,000	78,910,000
Write-off of fully depreciated assets	49,319,000	23,049,000
Deconsolidation of 1900 N Street	0	95,923,000
Fair value of OP Unit redemptions	(57,318,000)	(109,208,000)
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	35,318,000	0
Lease liabilities related to operating right-of-use assets (1)	37,922,000	0
Cash paid for amounts included in the measurement of lease liabilities for operating leases	$ 4,629,000	$ 0

Consolidated and Combined Sta_2

Consolidated and Combined Statements of Cash Flows (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Cash Flows [Abstract]
Capitalized interest	$ 8,258	$ 5,681	$ 23,211	$ 14,863

Organization and Basis of Prese

Organization and Basis of Presentation	9 Months Ended
	Sep. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Basis of Presentation	1. Organization and Basis of Presentation Organization JBG SMITH Properties ("JBG SMITH") was organized as a Maryland real estate investment trust ("REIT") on October 27, 2016 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, JBG SMITH acquired the management business and certain assets and liabilities (the "JBG Assets") of The JBG Companies ("JBG") (the "Combination"). The Separation and the Combination are collectively referred to as the "Formation Transaction." JBG SMITH is hereinafter referred to as "we," "us," "our" or similar terms. References to "our share" refers to our ownership percentage of consolidated and unconsolidated assets in real estate ventures. Substantially all of our assets are held by, and our operations are conducted through, JBG SMITH Properties LP ("JBG SMITH LP"), our operating partnership. As of September 30, 2019 , we, as its sole general partner, controlled JBG SMITH LP and owned 89.8% of its common limited partnership units ("OP Units"). We own and operate a portfolio of high-quality commercial and multifamily assets, many of which are amenitized with ancillary retail. Our portfolio reflects our 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 being within walking distance of a Metro station. As of September 30, 2019 , our Operating Portfolio consists of 61 operating assets comprising 45 commercial assets totaling approximately 12.7 million square feet ( 11.0 million square feet at our share) and 16 multifamily assets totaling 6,321 units ( 4,537 units at our share). Additionally, we have (i) eight assets under construction comprising four commercial assets totaling approximately 943,000 square feet ( 821,000 square feet at our share) and four multifamily assets totaling 1,476 units ( 1,298 units at our share); and (ii) 40 future development assets totaling approximately 21.9 million square feet ( 18.7 million square feet at our share) of estimated potential development density. Our revenues are derived primarily from leases with commercial and multifamily tenants, which include fixed 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 and the legacy funds (the "JBG Legacy Funds") formerly organized by JBG. 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 unaudited 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, 2019 and 2018 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, 2018 , filed with the Securities and Exchange Commission. The accompanying condensed consolidated financial statements include the accounts of JBG SMITH and our wholly owned subsidiaries and those other entities, including JBG SMITH LP, in which we have a controlling financial interest, including where we have been determined to be the primary beneficiary of a variable interest entity ("VIE"). See Note 5 for additional information on our VIEs. The portions of the equity and net income 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 the financial statements refer to our condensed consolidated financial statements as of September 30, 2019 and December 31, 2018 , and for the three and nine months ended September 30, 2019 and 2018 . References to the balance sheets refer to our condensed consolidated balance sheets as of September 30, 2019 and December 31, 2018 . References to the statements of operations refer to our condensed consolidated statements of operations for the three and nine months ended September 30, 2019 and 2018 . References to the statements of comprehensive income (loss) refer to our condensed consolidated statements of comprehensive income (loss) for the three and nine months ended September 30, 2019 and 2018 . References to the statements of cash flows refer to our condensed consolidated statements of cash flows for the nine months ended September 30, 2019 and 2018 . Reclassifications Certain prior period amounts have been reclassified to conform to the current period presentation as follows: • Reclassification of parking income totaling $6.4 million and $19.3 million previously included in "Property rentals" for the three and nine months ended September 30, 2018 to "Other income" in the statements of operations. • Reclassification of tenant reimbursements totaling $9.7 million and $28.7 million for the three and nine months ended September 30, 2018 to "Property rentals" in the statements of operations. • Reclassification of $4.2 million and $12.5 million of expenses incurred in the operation and management of our properties that were previously included in "General and administrative expense: corporate and other" for the three and nine months ended September 30, 2018 to "Property operating expenses" in the statements of operations. 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.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies 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, 2018 , except as follows related to our adoption of Accounting Standards Update ("ASU") 2016-02, Leases ("Topic 842") as of January 1, 2019. Prior to the adoption of Topic 842, leases were accounted under Topic 840, Leases ("Topic 840"). Revenue Recognition We have leases with various tenants across our portfolio of properties, which generate rental income and operating cash flows for our benefit. Through these leases, we provide tenants with the right to control the use of our real estate, which tenants agree to use and control. The right to control our real estate conveys to our tenants substantially all of the economic benefits and the right to direct how and for what purpose the real estate is used throughout the period of use, thereby meeting the definition of a lease. Leases will be classified as either operating, sales-type or direct finance leases based on whether the lease is structured in effect as a financed purchase. Property rentals revenue includes base rent each tenant pays in accordance with the terms of its respective lease and is reported on a straight-line basis over the non-cancellable term of the lease, which includes the effects of periodic step-ups in rent and rent abatements under the lease. When a renewal option is included within the lease, we assess whether the option is reasonably certain of being exercised against relevant economic factors to determine whether the option period should be included as part of the lease term. Further, property rentals revenue includes tenant reimbursements revenue from the recovery of all or a portion of the operating expenses and real estate taxes of the respective assets, which are accrued as variable lease payments in the same periods as the related expenses are incurred. We commence rental revenue recognition when the tenant takes possession of the leased space or controls the physical use of the leased space and when the leased space is substantially ready for its intended use. In circumstances where we provide a tenant improvement allowance for improvements that are owned by the tenant, we recognize the allowance as a reduction of property rentals revenue on a straight-line basis over the term of the lease. Differences between rental revenue recognized and amounts due under the respective lease agreements are recorded as an increase or decrease to "Deferred rent receivable, net" on our balance sheets. Property rentals revenue also includes the amortization or accretion of acquired above-and below-market leases. We periodically evaluate the collectability of amounts due from tenants and recognize an adjustment to property rental revenue for the estimated losses resulting from the inability of tenants to make required payments under lease agreements. Any changes to the provision for lease revenue determined to be not probable of collection are included in "Property rentals" in our statements of operations. We exercise judgment in assessing the probability of collection and consider payment history and current credit status in making this determination. Third-party real estate services revenue, including reimbursements, is determined in accordance with the terms specific to each arrangement and includes property and asset management fees and transactional fees for leasing, acquisition, development and construction, financing, and legal services. These fees are determined in accordance with the terms specific to each arrangement and are recognized as the related services are performed in accordance with ASU 2014-09, Revenue from Contracts with Customers, ("Topic 606"). 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 used in assessing impairment and (ii) the determination of useful lives for tangible and intangible assets. Actual results could differ from these estimates. Recent Accounting Pronouncements Adoption of Topic 842 We enter into various lease agreements to make our properties available for use by third parties in exchange for cash consideration or to obtain the right to use properties owned by third parties to administer our business operations. We account for these leases under Topic 842, which we adopted as of January 1, 2019 using a modified retrospective approach and by applying the several transitional practical expedients including the Comparatives Under 840 expedient, the Relief Package for existing leases and the Easement expedient for existing easements, but not the Hindsight expedient. The Comparatives Under 840 expedient allows us not to recast our comparative periods in the period of adoption, and the Relief Package and Easement expedients allow us to maintain our historical accounting conclusions on current leases as of the date of adoption with respect to whether a contract contains a lease, what a lease’s classification should be, what initial direct costs are capitalizable and whether a land easement constituted a lease. We made a policy election to forgo recording right-of-use assets and the related lease liabilities for leases with initial terms of 12 months or less. The adoption of Topic 842 did not result in a material change to our recognition of property rental revenue and did not impact our opening accumulated deficit balance, but resulted in: (i) the inclusion of tenant reimbursements in "Property rentals" in our statements of operations. Such amounts were previously separately presented as "Tenant reimbursements" in the statements of operations; (ii) the recognition, as of January 1, 2019, of right-of-use assets totaling $35.3 million in "Other assets, net" and lease liabilities totaling $37.9 million in "Other liabilities, net" in our accompanying balance sheet, associated with our corporate office lease and various ground leases for which we are the lessee. The initial right-of-use assets comprised $37.9 million of lease liabilities, $3.5 million of ground lease deferred rent payable reclassified from "Other liabilities, net" and $767,000 of identified net intangible assets and $140,000 of prepaid expenses both reclassified from "Other assets, net;" (iii) the inclusion as a deduction to revenue, as of January 1, 2019, of the impact of previously recognized revenue deemed improbable of collection. Such amounts were previously recognized within "Property operating expense" in the statements of operations; and (iv) the change, as of January 1, 2019, in our capitalization policy for direct leasing costs to include only incremental costs associated with successful leasing arrangements, which would not have been incurred if the leasing arrangements had not been obtained. As a result, we no longer capitalize internal leasing costs, which are now expensed as incurred within "Corporate and other - general and administrative costs" in the statements of operations. Internal leasing costs capitalized for the three and nine months ended September 30, 2018 totaled $1.5 million and $4.3 million . Lessor Accounting Leases in which we are the lessor provide for the payment of fixed base rents payable monthly as well as reimbursements of real estate taxes, insurance and maintenance costs. The reimbursement of real estate taxes, insurance and maintenance costs, which vary each period, are non-lease components that are not the predominant activity within the contract. We have elected a practical expedient which allows us to combine certain lease and non-lease components of our operating leases. Non-lease components are recognized together with fixed base rent in "Property rentals", as variable lease income in the same periods as the related expenses are incurred. Certain commercial leases may also provide for the payment by the lessee of additional rents based on a percentage of sales, which are recorded as variable lease income in the period the additional rents are earned. The following is a summary of revenue from our non-cancellable leases included in the statements of operations: Three Months Ended September 30, 2019 Nine Months Ended September 30, 2019 (In thousands) Property rentals: Fixed $ 114,538 $ 342,268 Variable 9,425 23,434 Total $ 123,963 $ 365,702 As of September 30, 2019 , the undiscounted cash flows to be received from lease payments under our operating leases on an annual basis for the next five years and thereafter are as follows: Year ending December 31, Amount (In thousands) 2019 (1) $ 101,929 2020 367,750 2021 307,251 2022 273,711 2023 235,298 2024 208,243 Thereafter 1,109,914 ______________ (1) Amount is for the remainder of 2019. As of December 31, 2018 , future base rental revenue under our non-cancellable operating leases, as determined under Topic 840, were as follows: Year ending December 31, Amount (In thousands) 2019 $ 377,427 2020 321,205 2021 287,463 2022 256,352 2023 215,203 Thereafter 1,188,767 Lessee Accounting We are obligated under non-cancellable operating leases, including ground leases on certain of our properties through 2061 and our corporate office leases. When a renewal option is included within a lease, we assess whether the option is reasonably certain of being exercised against relevant economic factors to determine whether the option period should be included as part of the lease term. Lease payments associated with renewal periods that we are reasonably certain will be exercised are included in the measurement of the corresponding lease liability and right-of-use asset. Rent expense for our operating leases is recognized on a straight-line basis over the expected lease term and is included in our statements of operations in either "Property operating expense" or "General and administrative expense" depending on the nature of the lease. Further, we are also obligated under a non-cancellable ground lease, which we classify as a finance lease. Because ownership of the land associated with this finance lease is reasonably certain to transfer to us upon the conclusion of the lease, we recorded $16.0 million to "Land and improvements" on our balance sheet when the lease commenced in 2017. Certain lease agreements include variable lease payments that, in the future, will vary based on changes in inflationary measures, market rates or our share of expenditures of the leased premises. Such variable payments are recognized in rent expense in the period in which the variability is determined. Certain lease agreements may also include various non-lease components that primarily relate to property operating expenses associated with our office leases, which also vary each period. We have elected the practical expedient which allows us not to separate lease and non-lease components for our ground and office leases and recognize variable non-lease components in rent expense when incurred. We discount our future lease payments for each lease to calculate the related lease liability using an estimated incremental borrowing rate computed based on observable corporate borrowing rates reflective of the general economic environment, taking into consideration our creditworthiness and various financing and asset specific considerations, adjusted to approximate a secured borrowing for the lease term. As of September 30, 2019 , the weighted average discount rate used in calculating lease liabilities for our active operating and finance leases were 5.3% and 5.8% , which have weighted average remaining lease terms of 20.7 years and 7.3 years . As of September 30, 2019 , future minimum lease payments under our non-cancellable operating and finance leases are as follows: Year ending December 31, Operating Finance (In thousands) 2019 (1) $ 1,573 $ 266 2020 6,272 1,073 2021 6,201 1,095 2022 5,257 1,117 2023 2,000 1,139 2024 2,061 1,162 Thereafter 36,579 15,977 Total future minimum lease payments 59,943 21,829 Imputed interest (25,403 ) (6,228 ) Total (2) $ 34,540 $ 15,601 ______________ (1) Amounts are for the remainder of 2019. (2) The total for operating leases of $34.5 million corresponds to lease liabilities related to operating right-of-use assets and the total for finance leases of $15.6 million represents our finance lease liability, both of which are included in "Other liabilities, net" as of September 30, 2019 . See Note 8 for additional information. As of December 31, 2018 , future minimum rental payments under our non-cancellable operating leases, capital leases and lease assumption liabilities, as determined under Topic 840, were as follows: Year ending December 31, Amount (In thousands) 2019 $ 13,991 2020 13,710 2021 13,395 2022 12,554 2023 9,489 Thereafter 55,780 Total $ 118,919 For the three and nine months ended September 30, 2019 , we incurred $662,000 and $1.9 million of fixed operating and finance lease costs and $437,000 and $1.3 million of variable operating lease costs.

Acquisition, Disposals and Asse

Acquisition, Disposals and Assets Held for Sale (Notes)	9 Months Ended
	Sep. 30, 2019
Discontinued Operations and Disposal Groups [Abstract]
Mergers, Acquisitions and Dispositions Disclosures [Text Block]	Acquisition, Dispositions and Assets Held for Sale Acquisition We have agreed, subject to customary closing conditions, to acquire F1RST Residences, a 325 -unit multifamily asset in the Ballpark submarket of Washington, D.C. with approximately 21,000 square feet of street level retail, for a purchase price of approximately $160.5 million . The multifamily portion of the building is 95.4% occupied as of September 30, 2019 . We expect the transaction to close by the end of 2019. We intend to use F1RST Residences as a replacement property in a like-kind exchange for the expected proceeds from the sale of Metropolitan Park to Amazon.com, Inc. ("Amazon"). Dispositions The following is a summary of disposition activity for the nine months ended September 30, 2019 : Date Disposed Assets Segment Location Total Square Feet Gross Sales Price Cash Proceeds from Sale Gain on Sale of Real Estate (In thousands) February 4, 2019 Commerce Executive / Commerce Metro Land (1) (2) Commercial / Other Reston, Virginia 388,562 $ 114,950 $ 117,676 $ 39,033 July 31, 2019 1600 K Street Commercial Washington, D.C. 82,653 43,000 40,134 8,088 Total 471,215 $ 157,950 $ 157,810 $ 47,121 ______________ (1) The sale also included approximately 894,000 square feet of estimated potential development density. The sale was part of a reverse like-kind exchange. See Note 5 for additional information. (2) Cash proceeds include the reimbursement of $4.0 million of tenant improvement costs and leasing commissions paid by us prior to the closing. Assets Held for Sale As of September 30, 2019 and December 31, 2018 , we had certain real estate properties that 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: Assets Segment Location Total Square Feet Assets Held for Sale Liabilities Related to Assets Held for Sale (In thousands) September 30, 2019 Pen Place (1) Other Arlington, Virginia — $ 74,107 $ — Metropolitan Park (1) Other Arlington, Virginia — 94,713 66 — $ 168,820 $ 66 December 31, 2018 Commerce Executive / Commerce Metro Land (2) Commercial Reston, Virginia 388,562 $ 78,981 $ 3,717 _______________ (1) In March 2019, we entered into agreements for the sale of Pen Place and Metropolitan Park, future development assets having an aggregate estimated potential development density of up to approximately 4.1 million square feet, for approximately $293.9 million , subject to customary closing conditions. (2) As noted above, we sold Commerce Executive/Commerce Metro Land in February 2019 .

Investments in and Advances to

Investments in and Advances to Unconsolidated Real Estate Ventures	9 Months Ended
	Sep. 30, 2019
Equity Method Investments and Joint Ventures [Abstract]
Investments in and Advances to Unconsolidated Real Estate Ventures	Investments in Unconsolidated Real Estate Ventures The following is a summary of the composition of our investments in unconsolidated real estate ventures: Real Estate Venture Partners Ownership Interest (1) September 30, 2019 December 31, 2018 (In thousands) CPPIB 55.0% $ 101,465 $ 97,521 Landmark 1.8% - 49.0% 78,979 84,320 CBREI Venture 5.0% - 64.0% 69,699 73,776 Berkshire Group 50.0% 45,974 43,937 Brandywine 30.0% 13,895 13,777 CIM Group and Pacific Life Insurance Company 16.7% 10,614 9,339 Other 294 208 Total investments in unconsolidated real estate ventures $ 320,920 $ 322,878 _______________ (1) Ownership interests as of September 30, 2019 . We have multiple investments with certain venture partners with varying ownership interests. As of September 30, 2019 and December 31, 2018 , we had a zero investment balance in the real estate venture that owns 1101 17th Street and suspended the equity method of accounting as of June 30, 2018. We will recognize as income any future distributions from the venture until our share of unrecorded earnings and contributions exceeds the cumulative excess distributions previously recognized in income. During the nine months ended September 30, 2019 , we recognized income of $6.4 million related to distributions from this venture, which is included in "Income from unconsolidated real estate ventures, net" in our statement of operations. During the nine months ended September 30, 2018 , we recognized the $5.4 million of negative investment balance as income within "Income from unconsolidated real estate ventures, net" in our statements of operations as a result of the venture refinancing a mortgage payable collateralized by the property and eliminating certain principal guaranty provisions that had been included in the prior loan. For the three and nine months ended September 30, 2018 , we recognized income of $890,000 related to a distribution from 1101 17th Street, which is included in "Income from unconsolidated real estate ventures, net" in our statement of operations. The following is a summary of the debt of our unconsolidated real estate ventures: Weighted Average Effective (1) September 30, 2019 December 31, 2018 (In thousands) Variable rate (2) 4.65% $ 627,787 $ 461,704 Fixed rate (3) 3.97% 548,591 665,662 Unconsolidated real estate ventures - mortgages payable 1,176,378 1,127,366 Unamortized deferred financing costs (1,905 ) (1,998 ) Unconsolidated real estate ventures - mortgages payable, net (4) $ 1,174,473 $ 1,125,368 ______________ (1) Weighted average effective interest rate as of September 30, 2019 . (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) See Note 15 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, 2019 December 31, 2018 Combined balance sheet information: (In thousands) Real estate, net $ 2,118,483 $ 2,050,985 Other assets, net (1) 192,128 169,264 Total assets $ 2,310,611 $ 2,220,249 Borrowings, net $ 1,174,473 $ 1,125,368 Other liabilities, net (1) 138,737 94,845 Total liabilities 1,313,210 1,220,213 Total equity 997,401 1,000,036 Total liabilities and equity $ 2,310,611 $ 2,220,249 ______________ (1) On January 1, 2019, our unconsolidated real estate ventures adopted Topic 842, which required the ventures to record operating right-of-use assets totaling $52.4 million and related lease liabilities totaling $44.1 million . Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Combined income statement information: (In thousands) Total revenue $ 65,110 $ 76,247 $ 199,897 $ 236,938 Operating income 10,925 6,861 21,034 23,719 Net loss (3,602 ) (6,970 ) (20,289 ) (12,159 )

Variable Interest Entities

Variable Interest Entities	9 Months Ended
	Sep. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Variable Interest Entities	Variable Interest Entities 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 the VIEs should be consolidated relate to our at-risk equity, our control over significant business activities, our voting rights, the noncontrolling interest kick-out rights and whether we are the primary beneficiary of the VIE. Unconsolidated VIEs As of September 30, 2019 and December 31, 2018 , 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, 2019 and December 31, 2018 , the net carrying amounts of our investment in these entities were $235.1 million and $232.8 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 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 debt guarantees. See Note 15 for additional information. Consolidated VIEs JBG SMITH LP is our most significant consolidated VIE. We hold the majority limited partnership interest in the operating partnership, act as the general partner and exercise full responsibility, discretion and control over its day-to-day management. The noncontrolling interests of the operating partnership 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, the operating partnership is a VIE. As general partner, we have the power to direct the core activities of the operating partnership that most significantly affect its performance, and through our majority interest in the operating partnership have both the right to receive benefits from and the obligation to absorb losses of the operating partnership. Accordingly, we are the primary beneficiary of the operating partnership and consolidate the operating partnership in our financial statements. As we conduct our business and hold our assets and liabilities through the operating partnership, the total assets and liabilities of the operating partnership comprise substantially all of our consolidated assets and liabilities. In conjunction with the acquisition of Potomac Yard Land Bay H located in Alexandria, Virginia in December 2018, we entered into a reverse like-kind exchange agreement with a third-party intermediary. Until the earlier of the termination of the exchange agreement or 180 days after the acquisition date, the third-party intermediary was the legal owner of the entity that owned this property. The agreement that governed the operations of this entity provided us with the power to direct the activities that most significantly impacted the entity's economic performance. This entity was deemed a VIE as of December 31, 2018 primarily because it may not have had sufficient equity at risk to finance its activities without additional subordinated financial support from other parties. We determined we were the primary beneficiary of the VIE as a result of having the power to direct the activities that most significantly impact its economic performance and the obligation to absorb losses, as well as the right to receive benefits, that could be potentially significant to the VIE. 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 after the sale of Commerce Executive/Commerce Metro Land in February 2019 . We consolidate VIEs in which we control the most significant business activities. These entities are VIEs because they are in the development stage and do not hold sufficient equity at risk. We are the primary beneficiaries of these VIEs because the noncontrolling interest holders do not have substantive kick-out or participating rights, and we control all of the significant business activities. As of September 30, 2019 , excluding the operating partnership, we consolidated one VIE with total assets and liabilities of $122.1 million and $17.0 million . As of December 31, 2018 , excluding the operating partnership, we consolidated two VIEs with total assets and liabilities of $94.8 million and $43.4 million

Other Assets, Net

Other Assets, Net	9 Months Ended
	Sep. 30, 2019
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Other Assets, Net	Other Assets, Net The following is a summary of other assets, net: September 30, 2019 December 31, 2018 (In thousands) Deferred leasing costs, net $ 143,590 $ 129,601 Lease intangible assets, net 24,084 34,390 Other identified intangible assets, net 50,395 55,469 Operating right-of-use assets, net (1) 31,795 — Prepaid expenses 20,011 6,482 Deferred financing costs on credit facility, net 3,392 4,806 Deposits 12,135 3,633 Derivative agreements, at fair value — 10,383 Other 16,358 20,230 Total other assets, net $ 301,760 $ 264,994 ______________ (1) Related to our adoption of Topic 842 on January 1, 2019. See Note 2 for additional information.

Debt

Debt	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Debt	Debt Mortgages Payable The following is a summary of mortgages payable: Weighted Average (1) September 30, 2019 December 31, 2018 (In thousands) Variable rate (2) 3.67% $ 14,000 $ 308,918 Fixed rate (3) 4.20% 1,347,840 1,535,734 Mortgages payable 1,361,840 1,844,652 Unamortized deferred financing costs and premium/ discount, net (3,269 ) (6,271 ) Mortgages payable, net $ 1,358,571 $ 1,838,381 __________________________ (1) Weighted average effective interest rate as of September 30, 2019 . (2) Includes a variable rate mortgage payable with an interest rate cap agreement as of December 31, 2018 . (3) Includes variable rate mortgages payable with interest rates fixed by interest rate swap agreements. As of September 30, 2019 and December 31, 2018 , the net carrying value of real estate collateralizing our mortgages payable, excluding assets held for sale, totaled $1.8 billion and $2.3 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 of our mortgages payable are recourse to us. See Note 15 for additional information. During the nine months ended September 30, 2019 , we repaid mortgages payable with an aggregate principal balance of $475.1 million , which resulted in a loss on the extinguishment of debt of $1.9 million , which is recognized within "Loss on extinguishment of debt" in the statement of operations. As of September 30, 2019 and December 31, 2018 , we had various interest rate swap and cap agreements with an aggregate notional value of $1.1 billion and $1.3 billion on certain of our mortgages payable. See Note 13 for additional information. Credit Facility We have a $1.4 billion credit facility, consisting of a $1.0 billion revolving credit facility maturing in July 2021 , with two six -month extension options, a delayed draw $200.0 million unsecured term loan ("Tranche A-1 Term Loan") maturing in January 2023 , and a delayed draw $200.0 million unsecured term loan ("Tranche A-2 Term Loan") maturing in July 2024 . Effective as of July 17, 2019, the credit facility was amended to extend the delayed draw period of our Tranche A-1 Term Loan to July 2020 and to reduce the applicable interest rate of the Tranche A-2 Term Loan by 40 basis points , to LIBOR plus 1.15% from LIBOR plus 1.55% . As of September 30, 2019 and December 31, 2018 , we had interest rate swaps with an aggregate notional value of $100.0 million , which effectively convert the variable interest rate applicable to our Tranche A-1 Term Loan to a fixed interest rate. As of September 30, 2019 , we had interest rate swaps with an aggregate notional value of $137.6 million , which effectively convert the variable interest rate applicable to a portion of the outstanding balance of our Tranche A-2 Term Loan to a fixed interest rate. The following is a summary of amounts outstanding under the credit facility: Interest Rate (1) September 30, 2019 December 31, 2018 (In thousands) Revolving credit facility (2) (3) (4) 3.12% $ — $ — Tranche A-1 Term Loan (5) 3.32% $ 100,000 $ 100,000 Tranche A-2 Term Loan (5) 3.82% 200,000 200,000 Unsecured term loans 300,000 300,000 Unamortized deferred financing costs, net (2,876 ) (2,871 ) Unsecured term loans, net $ 297,124 $ 297,129 __________________________ (1) Interest rate as of September 30, 2019 . (2) As of September 30, 2019 and December 31, 2018 , letters of credit with an aggregate face amount of $2.4 million and $5.7 million were provided under our revolving credit facility. (3) As of September 30, 2019 and December 31, 2018 , net deferred financing costs related to our revolving credit facility totaling $3.4 million and $4.8 million were included in "Other assets, net." (4) The interest rate for the revolving credit facility excludes a 0.15% facility fee. (5) The interest rate includes the impact of interest rate swap agreements.

Other Liabilities, Net

Other Liabilities, Net	9 Months Ended
	Sep. 30, 2019
Other Liabilities Disclosure [Abstract]
Other Liabilities, Net	Other Liabilities, Net The following is a summary of other liabilities, net: September 30, 2019 December 31, 2018 (In thousands) Lease intangible liabilities, net $ 12,243 $ 14,098 Prepaid rent 25,810 21,998 Lease assumption liabilities 21,856 23,105 Lease incentive liabilities 26,317 9,317 Lease liabilities related to operating right-of-use assets (1) 34,540 — Finance lease liability 15,601 15,704 Security deposits 16,573 17,696 Environmental liabilities 17,898 17,898 Ground lease deferred rent payable (2) — 3,510 Deferred tax liability 6,250 6,878 Dividends payable — 45,193 Derivative agreements, at fair value 27,577 1,723 Other 1,040 4,486 Total other liabilities, net $ 205,705 $ 181,606 __________________________ (1) Related to our adoption of Topic 842 on January 1, 2019. See Note 2 for additional information. (2) In connection with our adoption of Topic 842 on January 1, 2019, the ground lease deferred rent payable balance as of December 31, 2018 was included in the initial determination of the operating right-of-use assets. See Note 2 for additional information.

Redeemable Noncontrolling Inter

Redeemable Noncontrolling Interests	9 Months Ended
	Sep. 30, 2019
Noncontrolling Interest [Abstract]
Redeemable Noncontrolling Interests	Redeemable Noncontrolling Interests JBG SMITH LP A portion of the OP Units held by persons other than JBG SMITH became redeemable for cash or, at our election, our common shares beginning on August 1, 2018, subject to certain limitations. During the nine months ended September 30, 2019 , unitholders redeemed 1.7 million OP Units, which we elected to redeem for an equivalent number of our common shares. As of September 30, 2019 , outstanding OP Units totaled 15.2 million , representing a 10.2% ownership interest in JBG SMITH LP. On our balance sheets, our vested or outstanding redeemable noncontrolling interests are presented at the higher of their redemption value at the end of each reporting period 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. Consolidated Real Estate Venture We are a partner in a real estate venture that owns an under construction multifamily asset located at 965 Florida Avenue 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 two years after delivery, but no later than seven years subsequent to delivery. As of September 30, 2019 , we held a 94.2% ownership interest in the real estate venture. Below is a summary of the activity of redeemable noncontrolling interests: Three Months Ended September 30, 2019 2018 JBG SMITH LP Consolidated Real Estate Venture Total JBG SMITH LP Consolidated Real Estate Venture Total (In thousands) Balance as of beginning of period $ 568,242 $ 5,986 $ 574,228 $ 659,716 $ 5,907 $ 665,623 OP Unit redemptions — — — (109,208 ) — (109,208 ) Net income attributable to redeemable noncontrolling interests 1,172 — 1,172 3,552 — 3,552 Other comprehensive income (loss) (803 ) — (803 ) 696 — 696 Contributions (distributions) (3,831 ) — (3,831 ) (4,106 ) — (4,106 ) Share-based compensation expense 14,320 — 14,320 12,298 — 12,298 Adjustment to redemption value 1,446 — 1,446 (6,537 ) — (6,537 ) Balance as of end of period $ 580,546 $ 5,986 $ 586,532 $ 556,411 $ 5,907 $ 562,318 Nine Months Ended September 30, 2019 2018 JBG SMITH LP Consolidated Real Estate Venture Total JBG SMITH LP Consolidated Real Estate Venture Total (In thousands) Balance as of beginning of period $ 552,159 $ 5,981 $ 558,140 $ 603,717 $ 5,412 $ 609,129 OP Unit redemptions (57,318 ) — (57,318 ) (109,208 ) — (109,208 ) Long-term incentive partnership units ("LTIP Units") issued in lieu of cash bonuses (1) 3,954 — 3,954 — — — Net income (loss) attributable to redeemable noncontrolling interests 4,266 5 4,271 6,537 (5 ) 6,532 Other comprehensive income (loss) (3,689 ) — (3,689 ) 3,406 — 3,406 Contributions (distributions) (7,670 ) — (7,670 ) (8,763 ) 500 (8,263 ) Share-based compensation expense 45,937 — 45,937 39,376 — 39,376 Adjustment to redemption value 42,907 — 42,907 21,346 — 21,346 Balance as of end of period $ 580,546 $ 5,986 $ 586,532 $ 556,411 $ 5,907 $ 562,318

Share-Based Payments and Employ

Share-Based Payments and Employee Benefits	9 Months Ended
	Sep. 30, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-Based Payments and Employee Benefits	Share-Based Payments and Employee Benefits LTIP and Time-Based LTIP Units During the nine months ended September 30, 2019 , we granted 351,982 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 $34.26 per unit that vest primarily over four years , 25.0% per year, subject to continued employment. Compensation expense for these units is being recognized primarily 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, 2019 was $12.1 million valued using Monte Carlo simulations. During the nine months ended September 30, 2019 , we granted 91,636 of fully vested LTIP Units, with a grant-date fair value of $34.21 per unit, to certain executives who elected to receive all or a portion of their cash bonus paid in 2019, related to 2018 service, as LTIP Units. Compensation expense totaling $3.1 million for these LTIP Units was recognized in 2018. In May 2019, as part of their annual compensation, we granted a total of 50,159 fully vested LTIP Units to certain of our trustees with an aggregate grant-date fair value of $1.8 million . The significant assumptions used to value LTIP and Time-Based LTIP Units included: Expected volatility 18.0% to 24.0% Risk-free interest rate 2.3% to 2.6% Post-grant restriction periods 2 to 3 years Performance-Based LTIP Units During the nine months ended September 30, 2019 , we granted 478,411 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 $19.49 per unit. Our Performance-Based LTIP Units have a three -year performance period. Fifty percent of any Performance-Based LTIP Units that are earned vest at the end of the three -year performance period and the remaining 50% on the fourth anniversary of the date of grant, subject to continued employment. The aggregate grant-date fair value of the Performance-Based LTIP Units granted during the nine months ended September 30, 2019 was $9.3 million valued using Monte Carlo simulations. Compensation expense for the Performance-Based LTIP Units is being recognized over a four -year period. The significant assumptions used to value the Performance-Based LTIP Units included: Expected volatility 19.0% to 23.0% Dividend yield 2.3% to 2.5% Risk-free interest rate 2.3% to 2.6% ESPP Pursuant to the ESPP, employees purchased 25,575 common shares for $747,000 during the nine months ended September 30, 2019 . The significant assumptions used to value the ESPP common shares using the Black-Scholes model included expected volatility ( 28.0% ), dividend yield ( 2.6% ), risk-free interest rate ( 2.4% ) and expected life ( six months ). Share-Based Compensation Expense Share-based compensation expense is summarized as follows: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (In thousands) Time-Based LTIP Units $ 2,755 $ 2,520 $ 8,529 $ 7,772 Performance-Based LTIP Units 2,016 1,391 6,205 3,898 LTIP Units — — 1,000 794 Other equity awards (1) 1,403 989 3,443 2,693 Share-based compensation expense - other 6,174 4,900 19,177 15,157 Formation Awards 1,227 1,375 4,116 4,192 OP Units (2) 6,747 6,943 21,491 22,512 LTIP Units (2) 117 69 340 208 Special Performance-Based LTIP Units (3) 654 — 1,938 — Special Time-Based LTIP Units (3) 804 — 2,318 — Share-based compensation related to Formation Transaction and special equity awards (4) 9,549 8,387 30,203 26,912 Total share-based compensation expense 15,723 13,287 49,380 42,069 Less amount capitalized (406 ) (873 ) (1,948 ) (2,379 ) Share-based compensation expense $ 15,317 $ 12,414 $ 47,432 $ 39,690 ______________________________________________ (1) Includes 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 expense related to our employee share purchase plan. (2) Represents share-based compensation expense for LTIP Units and OP Units subject to post-Combination employment obligations. (3) Represents equity awards issued related to our successful pursuit of Amazon's additional headquarters in Northern Virginia. (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, 2019 , we had $94.7 million of total unrecognized compensation expense related to unvested share-based payment arrangements. This expense is expected to be recognized over a weighted average period of 2.3 years.

Interest Expense Interest Expen

Interest Expense Interest Expense	9 Months Ended
	Sep. 30, 2019
Interest Expense [Abstract]
Interest Income and Interest Expense Disclosure [Text Block]	Interest Expense The following is a summary of interest expense included in the statements of operations: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (In thousands) Interest expense $ 18,141 $ 23,465 $ 61,449 $ 69,024 Amortization of deferred financing costs 698 1,043 2,576 3,501 Net loss (gain) on derivative financial instruments Net unrealized 2 287 50 (1,264 ) Net realized — (135 ) — (135 ) Capitalized interest (8,258 ) (5,681 ) (23,211 ) (14,863 ) Interest expense $ 10,583 $ 18,979 $ 40,864 $ 56,263

Earnings Per Common Share

Earnings Per Common Share	9 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
Earnings Per Common Share	Earnings Per Common Share Shareholders' Equity In April 2019, we closed an underwritten public offering of 11.5 million common shares (including 1.5 million common shares related to the exercise of the underwriters' option to cover overallotments) at $42.00 per share, which generated net proceeds, after deducting the underwriting discounts and commissions and other offering expenses, of $472.8 million . We intend to use the balance sheet capacity generated by the net proceeds of the offering to fund development opportunities and for general corporate purposes. Earnings Per Common Share The following summarizes the calculation of basic and diluted earnings per common share and provides a reconciliation of the amounts of net income available to common shareholders used in calculating basic and diluted earnings per common share: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (In thousands, except per share amounts) Net income $ 10,532 $ 26,382 $ 35,452 $ 45,619 Net income attributable to redeemable noncontrolling interests (1,172 ) (3,552 ) (4,271 ) (6,532 ) Net loss attributable to noncontrolling interests — — — 127 Net income attributable to common shareholders 9,360 22,830 31,181 39,214 Distributions to participating securities (679 ) (153 ) (1,674 ) (527 ) Net income available to common shareholders — basic and diluted $ 8,681 $ 22,677 $ 29,507 $ 38,687 Weighted average number of common shares outstanding — basic and diluted 134,127 119,835 129,527 118,588 Earnings per common share: Basic $ 0.06 $ 0.19 $ 0.23 $ 0.33 Diluted $ 0.06 $ 0.19 $ 0.23 $ 0.33 The effect of the redemption of OP Units and Time-Based LTIP Units that were outstanding as of September 30, 2019 and 2018 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 and losses 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 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 4.7 million for the three and nine months ended September 30, 2019 and 3.9 million and 3.8 million for the three and nine months ended September 30, 2018

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements Financial Assets and Liabilities Measured at Fair Value 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, 2019 and December 31, 2018 , 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) gain on our derivative financial instruments designated as cash flow hedges was $(27.7) million and $8.3 million as of September 30, 2019 and December 31, 2018 and was recorded in "Accumulated other comprehensive income (loss)" in our balance sheets, of which a portion was reclassified to "Redeemable noncontrolling interests." Within the next 12 months, we expect to reclassify $6.3 million as an increase to interest expense. The net unrealized (loss) gain on our derivative financial instruments not designated as cash flow hedges was $(2,000) and $(50,000) for the three and nine months ended September 30, 2019 and $(287,000) and $1.3 million for the three and nine months ended September 30, 2018 , and is recorded in "Interest expense" in our statements of operations and "Net unrealized gain on derivative financial instruments not designated as cash flow hedges" in our statements of cash flows. Topic 820, Fair Value Measurement and Disclosures, 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 are assets and liabilities measured at fair value on a recurring basis: Fair Value Measurements Total Level 1 Level 2 Level 3 September 30, 2019 (In thousands) Derivative financial instruments designated as cash flow hedges: Classified as liabilities in "Other liabilities, net" $ 27,577 — $ 27,577 — December 31, 2018 Derivative financial instruments designated as cash flow hedges: Classified as assets in "Other assets, net" $ 7,913 $ — $ 7,913 $ — Classified as liabilities in "Other liabilities, net" 1,723 — 1,723 — Derivative financial instruments not designated as cash flow hedges: Classified as assets in "Other assets, net" 2,470 — 2,470 — 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, 2019 and December 31, 2018 , 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 income (loss)'' in our statements of comprehensive income (loss) for the three and nine months ended September 30, 2019 and 2018 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, 2019 and December 31, 2018 , 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, 2019 December 31, 2018 Carrying Amount (1) Fair Value Carrying Amount (1) Fair Value (In thousands) Financial liabilities: Mortgages payable $ 1,361,840 $ 1,404,849 $ 1,844,652 $ 1,870,078 Unsecured term loans 300,000 301,076 300,000 300,727 ______________________________________ ( 1) The carrying amount consists of principal only.

Segment Information

Segment Information	9 Months Ended
	Sep. 30, 2019
Segment Reporting [Abstract]
Segment Information	Segment Information We review operating and financial data for each property on an individual basis; therefore, each of our individual properties is a separate operating segment. As of December 31, 2018 , we redefined our reportable segments to be aligned with our new 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. To conform to the current period presentation, we have reclassified the prior period segment financial data for certain properties that had been classified as part of other to the commercial and multifamily segments, and the elimination of intersegment activity has been included as part of other for the three and nine months ended September 30, 2018 . The commercial segment was previously referred to as the office segment. 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 operating income, 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 revenues 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 disclosed separately in the statements of operations. Management company assets primarily consist of management and leasing contracts with a net book value of $33.3 million and $38.6 million and are classified in "Other assets, net" in the balance sheets as of September 30, 2019 and December 31, 2018 . 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 table reflects the reconciliation of net income attributable to common shareholders to consolidated NOI: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (In thousands) Net income attributable to common shareholders $ 9,360 $ 22,830 $ 31,181 $ 39,214 Add: Depreciation and amortization expense 46,862 46,603 141,576 143,880 General and administrative expense: Corporate and other 11,015 8,201 34,888 25,218 Third-party real estate services 29,809 20,754 86,585 64,552 Share-based compensation related to Formation Transaction and special equity awards 9,549 8,387 30,203 26,912 Transaction and other costs 2,059 4,126 9,928 12,134 Interest expense 10,583 18,979 40,864 56,263 Loss on extinguishment of debt — 79 1,889 4,536 Reduction of gain on bargain purchase — — — 7,606 Income tax expense (benefit) 432 (841 ) (689 ) (1,436 ) Net income attributable to redeemable noncontrolling 1,172 3,552 4,271 6,532 Less: Third-party real estate services, including reimbursements 34,587 23,788 91,765 72,278 Other income (1) 2,196 1,708 5,951 4,904 Income (loss) from unconsolidated real estate ventures, net (1,144 ) 13,484 647 15,418 Interest and other income (loss), net (640 ) 4,091 2,363 5,177 Gain on sale of real estate 8,088 11,938 47,121 45,789 Net loss attributable to noncontrolling interests — — — 127 Consolidated NOI $ 77,754 $ 77,661 $ 232,849 $ 241,718 __________________________ (1) Excludes parking income of $6.3 million and $6.4 million for the three months ended September 30, 2019 and 2018 , and $19.5 million and $19.3 million for the nine months ended September 30, 2019 and 2018 . Below 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, 2019 Commercial Multifamily Other Total (In thousands) Property rentals revenue $ 94,678 $ 28,946 $ 339 $ 123,963 Other property operating income 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 Three Months Ended September 30, 2018 Commercial Multifamily Other Total (In thousands) Property rentals revenue $ 99,011 $ 27,911 $ (342 ) $ 126,580 Other property operating income 6,244 94 29 6,367 Total property revenue 105,255 28,005 (313 ) 132,947 Property expense: Property operating 29,815 8,248 318 38,381 Real estate taxes 12,479 3,558 868 16,905 Total property expense 42,294 11,806 1,186 55,286 Consolidated NOI $ 62,961 $ 16,199 $ (1,499 ) $ 77,661 Nine Months Ended September 30, 2019 Commercial Multifamily Other Total (In thousands) Property rentals revenue $ 285,551 $ 86,069 $ (5,918 ) $ 365,702 Other property operating income 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 Nine Months Ended September 30, 2018 Commercial Multifamily Other Total (In thousands) Property rentals revenue $ 304,756 $ 80,452 $ (809 ) $ 384,399 Other property operating income 18,981 281 84 19,346 Total property revenue 323,737 80,733 (725 ) 403,745 Property expense: Property operating 85,862 23,247 (1,106 ) 108,003 Real estate taxes 39,477 10,721 3,826 54,024 Total property expense 125,339 33,968 2,720 162,027 Consolidated NOI $ 198,398 $ 46,765 $ (3,445 ) $ 241,718 The following is a summary of certain balance sheet data by segment: Commercial Multifamily Other Total September 30, 2019 (In thousands) Real estate, at cost $ 3,695,072 $ 1,798,854 $ 376,664 $ 5,870,590 Investments in unconsolidated real estate ventures 174,486 108,625 37,809 320,920 Total assets (1) 3,512,802 1,663,800 845,662 6,022,264 December 31, 2018 Real estate, at cost $ 3,634,472 $ 1,656,974 $ 501,288 $ 5,792,734 Investments in unconsolidated real estate ventures 177,173 109,232 36,473 322,878 Total assets (1) 3,707,255 1,528,177 761,853 5,997,285 __________________________ (1)

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Insurance We maintain general liability insurance with limits of $200.0 million per occurrence and in the aggregate, and property and rental value insurance coverage with limits of $2.0 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, 2019 , we have construction in progress that will require an additional $283.8 million to complete ( $238.0 million related to our consolidated entities and $45.7 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 two to three years . These capital expenditures are generally due as the work is performed, and we expect to finance them with debt proceeds, proceeds from asset recapitalizations and sales, issuance and sale of equity securities and available cash. Environmental Matters Each of our properties has been subjected to varying degrees of environmental assessment at various times. 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 total $17.9 million as of September 30, 2019 and December 31, 2018 , and primarily relate to a liability to remediate pre-existing environmental matters at Potomac Yard Land Bay H, which was acquired in December 2018. 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 (1) guarantee portions of the principal, interest and other amounts in connection with borrowings, (2) provide customary environmental indemnifications and nonrecourse carve-outs (e.g., guarantees against fraud, misrepresentation and bankruptcy) in connection with borrowings and (3) provide guarantees to lenders and other third parties for the completion of development projects. We customarily have agreements with our outside 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. Amounts that may be required to be paid in future periods in relation to budget overruns or operating losses that are also included in some of our guarantees are not estimable. Guarantees (excluding environmental) terminate either upon the satisfaction of specified circumstances or repayment of the underlying debt. At times, we have agreements with our outside partners whereby we agree to reimburse our partner for their share of any payments made by them under certain guarantees. As of September 30, 2019 , we had no principal payment guarantees for our unconsolidated real estate ventures. We also may guarantee portions of the principal, interest and other amounts in connection with the borrowings of our consolidated entities. As of September 30, 2019 , the aggregate amount of principal payment guarantees was $8.3 million for our consolidated entities. As of September 30, 2019 , we expect to fund additional capital to certain of our unconsolidated investments totaling approximately $47.1 million .

Transactions with Vornado and R

Transactions with Vornado and Related Parties	9 Months Ended
	Sep. 30, 2019
Related Party Transactions [Abstract]
Related Party Transactions Disclosure [Text Block]	Transactions with Vornado and Related Parties Transactions with Vornado In connection with the Formation Transaction, we entered into an agreement with Vornado under which Vornado provided operational support for a period that ended July 18, 2019. These services included information technology, financial reporting and payroll services. The charges for these services were based on an hourly or per transaction fee arrangement including reimbursement for overhead and out-of-pocket expenses totaling $931,000 and $3.2 million for the three and nine months ended September 30, 2018 . Charges for these services for 2019 were de minimis. Pursuant to agreements, we are providing Vornado with leasing and property management services for certain of its assets that were not part of the Separation. The total revenue related to these services was $536,000 and $1.5 million for the three and nine months ended September 30, 2019 , and $507,000 and $1.6 million for the three and nine months ended September 30, 2018 . We believe that the terms of these agreements are comparable to those that would have been negotiated based on market rates. We have agreements with Building Maintenance Services ("BMS"), a wholly owned subsidiary of Vornado, to supervise cleaning, engineering and security services at our properties. We paid BMS $5.5 million and $16.1 million for the three and nine months ended September 30, 2019 , and $5.4 million and $15.5 million during the three and nine months ended September 30, 2018 , which are included in "Property operating expenses" in our statements of operations. In connection with the Formation Transaction, we have a Tax Matters Agreement with Vornado. See Note 15 for additional information. Transactions with JBG Legacy Funds and the Washington Housing Initiative ("WHI") Our third-party asset management and real estate services business provides fee-based real estate services to third parties, the JBG Legacy Funds and the WHI. 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 of the JBG Assets to us, the general partner and managing member interests in 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. To date, the WHI Impact Pool ("Impact Pool") completed closings of capital commitments totaling $93.7 million , which included a commitment from us of $9.1 million . We are the third-party manager for the Impact Pool, which is the social impact investment vehicle of the WHI. The third-party real estate services revenue, including expense reimbursements, from these JBG Legacy Funds and the Impact Pool was $10.2 million and $28.6 million for the three and nine months ended September 30, 2019 , and $8.7 million and $25.6 million for the three and nine months ended September 30, 2018 . As of September 30, 2019 and December 31, 2018 , we had receivables from the JBG Legacy Funds and the Impact Pool totaling $6.9 million and $3.6 million for such services. We rent our corporate offices from an unconsolidated real estate venture and incurred expenses totaling $1.3 million and $3.8 million for the three and nine months ended September 30, 2019 and $1.2 million and $3.6 million for the three and nine months ended September 30, 2018 , which is recorded in "General and administrative expense" in our statements of operations.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2019
Subsequent Events [Abstract]
Subsequent Events	Subsequent Event In October 2019, our Board of Trustees declared a quarterly dividend of $0.225 per common share, payable on November 29, 2019 to shareholders of record as of November 14, 2019 .

Organization and Basis of Pre_2

Organization and Basis of Presentation Accounting (Policies)	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Basis of Accounting [Text Block]	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 unaudited 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, 2019 and 2018 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, 2018 , filed with the Securities and Exchange Commission. The accompanying condensed consolidated financial statements include the accounts of JBG SMITH and our wholly owned subsidiaries and those other entities, including JBG SMITH LP, in which we have a controlling financial interest, including where we have been determined to be the primary beneficiary of a variable interest entity ("VIE"). See Note 5 for additional information on our VIEs. The portions of the equity and net income 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 the financial statements refer to our condensed consolidated financial statements as of September 30, 2019 and December 31, 2018 , and for the three and nine months ended September 30, 2019 and 2018 . References to the balance sheets refer to our condensed consolidated balance sheets as of September 30, 2019 and December 31, 2018 . References to the statements of operations refer to our condensed consolidated statements of operations for the three and nine months ended September 30, 2019 and 2018 . References to the statements of comprehensive income (loss) refer to our condensed consolidated statements of comprehensive income (loss) for the three and nine months ended September 30, 2019 and 2018 . References to the statements of cash flows refer to our condensed consolidated statements of cash flows for the nine months ended September 30, 2019 and 2018 .
Income Tax, Policy [Policy Text Block]	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.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Revenue Recognition, Policy [Policy Text Block]	Revenue Recognition We have leases with various tenants across our portfolio of properties, which generate rental income and operating cash flows for our benefit. Through these leases, we provide tenants with the right to control the use of our real estate, which tenants agree to use and control. The right to control our real estate conveys to our tenants substantially all of the economic benefits and the right to direct how and for what purpose the real estate is used throughout the period of use, thereby meeting the definition of a lease. Leases will be classified as either operating, sales-type or direct finance leases based on whether the lease is structured in effect as a financed purchase. Property rentals revenue includes base rent each tenant pays in accordance with the terms of its respective lease and is reported on a straight-line basis over the non-cancellable term of the lease, which includes the effects of periodic step-ups in rent and rent abatements under the lease. When a renewal option is included within the lease, we assess whether the option is reasonably certain of being exercised against relevant economic factors to determine whether the option period should be included as part of the lease term. Further, property rentals revenue includes tenant reimbursements revenue from the recovery of all or a portion of the operating expenses and real estate taxes of the respective assets, which are accrued as variable lease payments in the same periods as the related expenses are incurred. We commence rental revenue recognition when the tenant takes possession of the leased space or controls the physical use of the leased space and when the leased space is substantially ready for its intended use. In circumstances where we provide a tenant improvement allowance for improvements that are owned by the tenant, we recognize the allowance as a reduction of property rentals revenue on a straight-line basis over the term of the lease. Differences between rental revenue recognized and amounts due under the respective lease agreements are recorded as an increase or decrease to "Deferred rent receivable, net" on our balance sheets. Property rentals revenue also includes the amortization or accretion of acquired above-and below-market leases. We periodically evaluate the collectability of amounts due from tenants and recognize an adjustment to property rental revenue for the estimated losses resulting from the inability of tenants to make required payments under lease agreements. Any changes to the provision for lease revenue determined to be not probable of collection are included in "Property rentals" in our statements of operations. We exercise judgment in assessing the probability of collection and consider payment history and current credit status in making this determination. Third-party real estate services revenue, including reimbursements, is determined in accordance with the terms specific to each arrangement and includes property and asset management fees and transactional fees for leasing, acquisition, development and construction, financing, and legal services. These fees are determined in accordance with the terms specific to each arrangement and are recognized as the related services are performed in accordance with ASU 2014-09, Revenue from Contracts with Customers, ("Topic 606").
Use of Estimates, Policy [Policy Text Block]	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 used in assessing impairment and (ii) the determination of useful lives for tangible and intangible assets. Actual results could differ from these estimates.
New Accounting Pronouncements, Policy [Policy Text Block]	Recent Accounting Pronouncements Adoption of Topic 842 We enter into various lease agreements to make our properties available for use by third parties in exchange for cash consideration or to obtain the right to use properties owned by third parties to administer our business operations. We account for these leases under Topic 842, which we adopted as of January 1, 2019 using a modified retrospective approach and by applying the several transitional practical expedients including the Comparatives Under 840 expedient, the Relief Package for existing leases and the Easement expedient for existing easements, but not the Hindsight expedient. The Comparatives Under 840 expedient allows us not to recast our comparative periods in the period of adoption, and the Relief Package and Easement expedients allow us to maintain our historical accounting conclusions on current leases as of the date of adoption with respect to whether a contract contains a lease, what a lease’s classification should be, what initial direct costs are capitalizable and whether a land easement constituted a lease. We made a policy election to forgo recording right-of-use assets and the related lease liabilities for leases with initial terms of 12 months or less. The adoption of Topic 842 did not result in a material change to our recognition of property rental revenue and did not impact our opening accumulated deficit balance, but resulted in: (i) the inclusion of tenant reimbursements in "Property rentals" in our statements of operations. Such amounts were previously separately presented as "Tenant reimbursements" in the statements of operations; (ii) the recognition, as of January 1, 2019, of right-of-use assets totaling $35.3 million in "Other assets, net" and lease liabilities totaling $37.9 million in "Other liabilities, net" in our accompanying balance sheet, associated with our corporate office lease and various ground leases for which we are the lessee. The initial right-of-use assets comprised $37.9 million of lease liabilities, $3.5 million of ground lease deferred rent payable reclassified from "Other liabilities, net" and $767,000 of identified net intangible assets and $140,000 of prepaid expenses both reclassified from "Other assets, net;" (iii) the inclusion as a deduction to revenue, as of January 1, 2019, of the impact of previously recognized revenue deemed improbable of collection. Such amounts were previously recognized within "Property operating expense" in the statements of operations; and (iv) the change, as of January 1, 2019, in our capitalization policy for direct leasing costs to include only incremental costs associated with successful leasing arrangements, which would not have been incurred if the leasing arrangements had not been obtained. As a result, we no longer capitalize internal leasing costs, which are now expensed as incurred within "Corporate and other - general and administrative costs" in the statements of operations. Internal leasing costs capitalized for the three and nine months ended September 30, 2018 totaled $1.5 million and $4.3 million . Lessor Accounting Leases in which we are the lessor provide for the payment of fixed base rents payable monthly as well as reimbursements of real estate taxes, insurance and maintenance costs. The reimbursement of real estate taxes, insurance and maintenance costs, which vary each period, are non-lease components that are not the predominant activity within the contract. We have elected a practical expedient which allows us to combine certain lease and non-lease components of our operating leases. Non-lease components are recognized together with fixed base rent in "Property rentals", as variable lease income in the same periods as the related expenses are incurred. Certain commercial leases may also provide for the payment by the lessee of additional rents based on a percentage of sales, which are recorded as variable lease income in the period the additional rents are earned. The following is a summary of revenue from our non-cancellable leases included in the statements of operations: Three Months Ended September 30, 2019 Nine Months Ended September 30, 2019 (In thousands) Property rentals: Fixed $ 114,538 $ 342,268 Variable 9,425 23,434 Total $ 123,963 $ 365,702 As of September 30, 2019 , the undiscounted cash flows to be received from lease payments under our operating leases on an annual basis for the next five years and thereafter are as follows: Year ending December 31, Amount (In thousands) 2019 (1) $ 101,929 2020 367,750 2021 307,251 2022 273,711 2023 235,298 2024 208,243 Thereafter 1,109,914 ______________ (1) Amount is for the remainder of 2019. As of December 31, 2018 , future base rental revenue under our non-cancellable operating leases, as determined under Topic 840, were as follows: Year ending December 31, Amount (In thousands) 2019 $ 377,427 2020 321,205 2021 287,463 2022 256,352 2023 215,203 Thereafter 1,188,767 Lessee Accounting We are obligated under non-cancellable operating leases, including ground leases on certain of our properties through 2061 and our corporate office leases. When a renewal option is included within a lease, we assess whether the option is reasonably certain of being exercised against relevant economic factors to determine whether the option period should be included as part of the lease term. Lease payments associated with renewal periods that we are reasonably certain will be exercised are included in the measurement of the corresponding lease liability and right-of-use asset. Rent expense for our operating leases is recognized on a straight-line basis over the expected lease term and is included in our statements of operations in either "Property operating expense" or "General and administrative expense" depending on the nature of the lease. Further, we are also obligated under a non-cancellable ground lease, which we classify as a finance lease. Because ownership of the land associated with this finance lease is reasonably certain to transfer to us upon the conclusion of the lease, we recorded $16.0 million to "Land and improvements" on our balance sheet when the lease commenced in 2017. Certain lease agreements include variable lease payments that, in the future, will vary based on changes in inflationary measures, market rates or our share of expenditures of the leased premises. Such variable payments are recognized in rent expense in the period in which the variability is determined. Certain lease agreements may also include various non-lease components that primarily relate to property operating expenses associated with our office leases, which also vary each period. We have elected the practical expedient which allows us not to separate lease and non-lease components for our ground and office leases and recognize variable non-lease components in rent expense when incurred. We discount our future lease payments for each lease to calculate the related lease liability using an estimated incremental borrowing rate computed based on observable corporate borrowing rates reflective of the general economic environment, taking into consideration our creditworthiness and various financing and asset specific considerations, adjusted to approximate a secured borrowing for the lease term. As of September 30, 2019 , the weighted average discount rate used in calculating lease liabilities for our active operating and finance leases were 5.3% and 5.8% , which have weighted average remaining lease terms of 20.7 years and 7.3 years . As of September 30, 2019 , future minimum lease payments under our non-cancellable operating and finance leases are as follows: Year ending December 31, Operating Finance (In thousands) 2019 (1) $ 1,573 $ 266 2020 6,272 1,073 2021 6,201 1,095 2022 5,257 1,117 2023 2,000 1,139 2024 2,061 1,162 Thereafter 36,579 15,977 Total future minimum lease payments 59,943 21,829 Imputed interest (25,403 ) (6,228 ) Total (2) $ 34,540 $ 15,601 ______________ (1) Amounts are for the remainder of 2019. (2) The total for operating leases of $34.5 million corresponds to lease liabilities related to operating right-of-use assets and the total for finance leases of $15.6 million represents our finance lease liability, both of which are included in "Other liabilities, net" as of September 30, 2019 . See Note 8 for additional information. As of December 31, 2018 , future minimum rental payments under our non-cancellable operating leases, capital leases and lease assumption liabilities, as determined under Topic 840, were as follows: Year ending December 31, Amount (In thousands) 2019 $ 13,991 2020 13,710 2021 13,395 2022 12,554 2023 9,489 Thereafter 55,780 Total $ 118,919 For the three and nine months ended September 30, 2019 , we incurred $662,000 and $1.9 million of fixed operating and finance lease costs and $437,000 and $1.3 million of variable operating lease costs.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Operating Lease, Lease Income [Table Text Block]	As of September 30, 2019 , the undiscounted cash flows to be received from lease payments under our operating leases on an annual basis for the next five years and thereafter are as follows: Year ending December 31, Amount (In thousands) 2019 (1) $ 101,929 2020 367,750 2021 307,251 2022 273,711 2023 235,298 2024 208,243 Thereafter 1,109,914 The following is a summary of revenue from our non-cancellable leases included in the statements of operations: Three Months Ended September 30, 2019 Nine Months Ended September 30, 2019 (In thousands) Property rentals: Fixed $ 114,538 $ 342,268 Variable 9,425 23,434 Total $ 123,963 $ 365,702
Schedule of Future Minimum Lease Payments for Operating and Finance Leases [Table Text Block]	As of September 30, 2019 , future minimum lease payments under our non-cancellable operating and finance leases are as follows: Year ending December 31, Operating Finance (In thousands) 2019 (1) $ 1,573 $ 266 2020 6,272 1,073 2021 6,201 1,095 2022 5,257 1,117 2023 2,000 1,139 2024 2,061 1,162 Thereafter 36,579 15,977 Total future minimum lease payments 59,943 21,829 Imputed interest (25,403 ) (6,228 ) Total (2) $ 34,540 $ 15,601 ______________ (1) Amounts are for the remainder of 2019. (2) The total for operating leases of $34.5 million corresponds to lease liabilities related to operating right-of-use assets and the total for finance leases of $15.6 million represents our finance lease liability, both of which are included in "Other liabilities, net" as of September 30, 2019 . See Note 8 for additional information.
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	As of December 31, 2018 , future base rental revenue under our non-cancellable operating leases, as determined under Topic 840, were as follows: Year ending December 31, Amount (In thousands) 2019 $ 377,427 2020 321,205 2021 287,463 2022 256,352 2023 215,203 Thereafter 1,188,767
Schedule of Future Minimum Lease Payments for Capital and Operating Leases [Table Text Block]	As of December 31, 2018 , future minimum rental payments under our non-cancellable operating leases, capital leases and lease assumption liabilities, as determined under Topic 840, were as follows: Year ending December 31, Amount (In thousands) 2019 $ 13,991 2020 13,710 2021 13,395 2022 12,554 2023 9,489 Thereafter 55,780 Total $ 118,919

Acquisition, Disposals and As_2

Acquisition, Disposals and Assets Held for Sale (Tables)	9 Months Ended
	Sep. 30, 2019
Discontinued Operations and Disposal Groups [Abstract]
Disclosure of Long Lived Assets Held-for-sale [Table Text Block]	The following is a summary of assets held for sale: Assets Segment Location Total Square Feet Assets Held for Sale Liabilities Related to Assets Held for Sale (In thousands) September 30, 2019 Pen Place (1) Other Arlington, Virginia — $ 74,107 $ — Metropolitan Park (1) Other Arlington, Virginia — 94,713 66 — $ 168,820 $ 66 December 31, 2018 Commerce Executive / Commerce Metro Land (2) Commercial Reston, Virginia 388,562 $ 78,981 $ 3,717 _______________ (1) In March 2019, we entered into agreements for the sale of Pen Place and Metropolitan Park, future development assets having an aggregate estimated potential development density of up to approximately 4.1 million square feet, for approximately $293.9 million , subject to customary closing conditions. (2) As noted above, we sold Commerce Executive/Commerce Metro Land in February 2019
Disposal Groups, Including Discontinued Operations [Table Text Block]	The following is a summary of disposition activity for the nine months ended September 30, 2019 : Date Disposed Assets Segment Location Total Square Feet Gross Sales Price Cash Proceeds from Sale Gain on Sale of Real Estate (In thousands) February 4, 2019 Commerce Executive / Commerce Metro Land (1) (2) Commercial / Other Reston, Virginia 388,562 $ 114,950 $ 117,676 $ 39,033 July 31, 2019 1600 K Street Commercial Washington, D.C. 82,653 43,000 40,134 8,088 Total 471,215 $ 157,950 $ 157,810 $ 47,121 ______________ (1) The sale also included approximately 894,000 square feet of estimated potential development density. The sale was part of a reverse like-kind exchange. See Note 5 for additional information. (2) Cash proceeds include the reimbursement of $4.0 million of tenant improvement costs and leasing commissions paid by us prior to the closing.

Investments in and Advances t_2

Investments in and Advances to Unconsolidated Real Estate Ventures (Tables)	9 Months Ended
	Sep. 30, 2019
Equity Method Investments and Joint Ventures [Abstract]
Composition of Investments	The following is a summary of the debt of our unconsolidated real estate ventures: Weighted Average Effective (1) September 30, 2019 December 31, 2018 (In thousands) Variable rate (2) 4.65% $ 627,787 $ 461,704 Fixed rate (3) 3.97% 548,591 665,662 Unconsolidated real estate ventures - mortgages payable 1,176,378 1,127,366 Unamortized deferred financing costs (1,905 ) (1,998 ) Unconsolidated real estate ventures - mortgages payable, net (4) $ 1,174,473 $ 1,125,368 ______________ (1) Weighted average effective interest rate as of September 30, 2019 . (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) See Note 15 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, 2019 December 31, 2018 Combined balance sheet information: (In thousands) Real estate, net $ 2,118,483 $ 2,050,985 Other assets, net (1) 192,128 169,264 Total assets $ 2,310,611 $ 2,220,249 Borrowings, net $ 1,174,473 $ 1,125,368 Other liabilities, net (1) 138,737 94,845 Total liabilities 1,313,210 1,220,213 Total equity 997,401 1,000,036 Total liabilities and equity $ 2,310,611 $ 2,220,249 ______________ (1) On January 1, 2019, our unconsolidated real estate ventures adopted Topic 842, which required the ventures to record operating right-of-use assets totaling $52.4 million and related lease liabilities totaling $44.1 million . Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Combined income statement information: (In thousands) Total revenue $ 65,110 $ 76,247 $ 199,897 $ 236,938 Operating income 10,925 6,861 21,034 23,719 Net loss (3,602 ) (6,970 ) (20,289 ) (12,159 ) The following is a summary of the composition of our investments in unconsolidated real estate ventures: Real Estate Venture Partners Ownership Interest (1) September 30, 2019 December 31, 2018 (In thousands) CPPIB 55.0% $ 101,465 $ 97,521 Landmark 1.8% - 49.0% 78,979 84,320 CBREI Venture 5.0% - 64.0% 69,699 73,776 Berkshire Group 50.0% 45,974 43,937 Brandywine 30.0% 13,895 13,777 CIM Group and Pacific Life Insurance Company 16.7% 10,614 9,339 Other 294 208 Total investments in unconsolidated real estate ventures $ 320,920 $ 322,878 _______________ (1) Ownership interests as of September 30, 2019 . We have multiple investments with certain venture partners with varying ownership interests.

Other Assets, Net (Tables)

Other Assets, Net (Tables)	9 Months Ended
	Sep. 30, 2019
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Summary of Other Assets, Net	The following is a summary of other assets, net: September 30, 2019 December 31, 2018 (In thousands) Deferred leasing costs, net $ 143,590 $ 129,601 Lease intangible assets, net 24,084 34,390 Other identified intangible assets, net 50,395 55,469 Operating right-of-use assets, net (1) 31,795 — Prepaid expenses 20,011 6,482 Deferred financing costs on credit facility, net 3,392 4,806 Deposits 12,135 3,633 Derivative agreements, at fair value — 10,383 Other 16,358 20,230 Total other assets, net $ 301,760 $ 264,994

Debt (Tables)

Debt (Tables)	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Summary of Debt	The following is a summary of amounts outstanding under the credit facility: Interest Rate (1) September 30, 2019 December 31, 2018 (In thousands) Revolving credit facility (2) (3) (4) 3.12% $ — $ — Tranche A-1 Term Loan (5) 3.32% $ 100,000 $ 100,000 Tranche A-2 Term Loan (5) 3.82% 200,000 200,000 Unsecured term loans 300,000 300,000 Unamortized deferred financing costs, net (2,876 ) (2,871 ) Unsecured term loans, net $ 297,124 $ 297,129 __________________________ (1) Interest rate as of September 30, 2019 . (2) As of September 30, 2019 and December 31, 2018 , letters of credit with an aggregate face amount of $2.4 million and $5.7 million were provided under our revolving credit facility. (3) As of September 30, 2019 and December 31, 2018 , net deferred financing costs related to our revolving credit facility totaling $3.4 million and $4.8 million were included in "Other assets, net." (4) The interest rate for the revolving credit facility excludes a 0.15% The following is a summary of mortgages payable: Weighted Average (1) September 30, 2019 December 31, 2018 (In thousands) Variable rate (2) 3.67% $ 14,000 $ 308,918 Fixed rate (3) 4.20% 1,347,840 1,535,734 Mortgages payable 1,361,840 1,844,652 Unamortized deferred financing costs and premium/ discount, net (3,269 ) (6,271 ) Mortgages payable, net $ 1,358,571 $ 1,838,381 __________________________ (1) Weighted average effective interest rate as of September 30, 2019 . (2) Includes a variable rate mortgage payable with an interest rate cap agreement as of December 31, 2018 . (3) Includes variable rate mortgages payable with interest rates fixed by interest rate swap agreements.

Other Liabilities, Net (Tables)

Other Liabilities, Net (Tables)	9 Months Ended
	Sep. 30, 2019
Other Liabilities Disclosure [Abstract]
Composition of Other Liabilities, Net	The following is a summary of other liabilities, net: September 30, 2019 December 31, 2018 (In thousands) Lease intangible liabilities, net $ 12,243 $ 14,098 Prepaid rent 25,810 21,998 Lease assumption liabilities 21,856 23,105 Lease incentive liabilities 26,317 9,317 Lease liabilities related to operating right-of-use assets (1) 34,540 — Finance lease liability 15,601 15,704 Security deposits 16,573 17,696 Environmental liabilities 17,898 17,898 Ground lease deferred rent payable (2) — 3,510 Deferred tax liability 6,250 6,878 Dividends payable — 45,193 Derivative agreements, at fair value 27,577 1,723 Other 1,040 4,486 Total other liabilities, net $ 205,705 $ 181,606

Redeemable Noncontrolling Int_2

Redeemable Noncontrolling Interests (Tables)	9 Months Ended
	Sep. 30, 2019
Noncontrolling Interest [Abstract]
Redeemable Noncontrolling Interests	Below is a summary of the activity of redeemable noncontrolling interests: Three Months Ended September 30, 2019 2018 JBG SMITH LP Consolidated Real Estate Venture Total JBG SMITH LP Consolidated Real Estate Venture Total (In thousands) Balance as of beginning of period $ 568,242 $ 5,986 $ 574,228 $ 659,716 $ 5,907 $ 665,623 OP Unit redemptions — — — (109,208 ) — (109,208 ) Net income attributable to redeemable noncontrolling interests 1,172 — 1,172 3,552 — 3,552 Other comprehensive income (loss) (803 ) — (803 ) 696 — 696 Contributions (distributions) (3,831 ) — (3,831 ) (4,106 ) — (4,106 ) Share-based compensation expense 14,320 — 14,320 12,298 — 12,298 Adjustment to redemption value 1,446 — 1,446 (6,537 ) — (6,537 ) Balance as of end of period $ 580,546 $ 5,986 $ 586,532 $ 556,411 $ 5,907 $ 562,318 Nine Months Ended September 30, 2019 2018 JBG SMITH LP Consolidated Real Estate Venture Total JBG SMITH LP Consolidated Real Estate Venture Total (In thousands) Balance as of beginning of period $ 552,159 $ 5,981 $ 558,140 $ 603,717 $ 5,412 $ 609,129 OP Unit redemptions (57,318 ) — (57,318 ) (109,208 ) — (109,208 ) Long-term incentive partnership units ("LTIP Units") issued in lieu of cash bonuses (1) 3,954 — 3,954 — — — Net income (loss) attributable to redeemable noncontrolling interests 4,266 5 4,271 6,537 (5 ) 6,532 Other comprehensive income (loss) (3,689 ) — (3,689 ) 3,406 — 3,406 Contributions (distributions) (7,670 ) — (7,670 ) (8,763 ) 500 (8,263 ) Share-based compensation expense 45,937 — 45,937 39,376 — 39,376 Adjustment to redemption value 42,907 — 42,907 21,346 — 21,346 Balance as of end of period $ 580,546 $ 5,986 $ 586,532 $ 556,411 $ 5,907 $ 562,318

Share-Based Payments (Tables)

Share-Based Payments (Tables)	9 Months Ended
	Sep. 30, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Disclosure of Share-based Compensation Arrangements by Share-based Payment Award [Table Text Block]	The significant assumptions used to value LTIP and Time-Based LTIP Units included: Expected volatility 18.0% to 24.0% Risk-free interest rate 2.3% to 2.6% Post-grant restriction periods 2 to 3 years Expected volatility 19.0% to 23.0% Dividend yield 2.3% to 2.5% Risk-free interest rate 2.3% to 2.6% ESPP Pursuant to the ESPP, employees purchased 25,575 common shares for $747,000 during the nine months ended September 30, 2019 . The significant assumptions used to value the ESPP common shares using the Black-Scholes model included expected volatility ( 28.0% ), dividend yield ( 2.6% ), risk-free interest rate ( 2.4% ) and expected life ( six months ).
Summary of Share-Based Compensation Expense	Share-based compensation expense is summarized as follows: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (In thousands) Time-Based LTIP Units $ 2,755 $ 2,520 $ 8,529 $ 7,772 Performance-Based LTIP Units 2,016 1,391 6,205 3,898 LTIP Units — — 1,000 794 Other equity awards (1) 1,403 989 3,443 2,693 Share-based compensation expense - other 6,174 4,900 19,177 15,157 Formation Awards 1,227 1,375 4,116 4,192 OP Units (2) 6,747 6,943 21,491 22,512 LTIP Units (2) 117 69 340 208 Special Performance-Based LTIP Units (3) 654 — 1,938 — Special Time-Based LTIP Units (3) 804 — 2,318 — Share-based compensation related to Formation Transaction and special equity awards (4) 9,549 8,387 30,203 26,912 Total share-based compensation expense 15,723 13,287 49,380 42,069 Less amount capitalized (406 ) (873 ) (1,948 ) (2,379 ) Share-based compensation expense $ 15,317 $ 12,414 $ 47,432 $ 39,690 ______________________________________________ (1) Includes 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 expense related to our employee share purchase plan. (2) Represents share-based compensation expense for LTIP Units and OP Units subject to post-Combination employment obligations. (3) Represents equity awards issued related to our successful pursuit of Amazon's additional headquarters in Northern Virginia. (4) Included in "General and administrative expense: Share-based compensation related to Formation Transaction and special equity awards" in the accompanying statements of operations.

Interest Expense Interest Exp_2

Interest Expense Interest Expense (Tables)	9 Months Ended
	Sep. 30, 2019
Interest Expense [Abstract]
Interest Income and Interest Expense Disclosure [Table Text Block]	The following is a summary of interest expense included in the statements of operations: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (In thousands) Interest expense $ 18,141 $ 23,465 $ 61,449 $ 69,024 Amortization of deferred financing costs 698 1,043 2,576 3,501 Net loss (gain) on derivative financial instruments Net unrealized 2 287 50 (1,264 ) Net realized — (135 ) — (135 ) Capitalized interest (8,258 ) (5,681 ) (23,211 ) (14,863 ) Interest expense $ 10,583 $ 18,979 $ 40,864 $ 56,263

Shareholders' Equity and Earnin

Shareholders' Equity and Earnings Per Common Share EPS (Tables)	9 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]	The following summarizes the calculation of basic and diluted earnings per common share and provides a reconciliation of the amounts of net income available to common shareholders used in calculating basic and diluted earnings per common share: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (In thousands, except per share amounts) Net income $ 10,532 $ 26,382 $ 35,452 $ 45,619 Net income attributable to redeemable noncontrolling interests (1,172 ) (3,552 ) (4,271 ) (6,532 ) Net loss attributable to noncontrolling interests — — — 127 Net income attributable to common shareholders 9,360 22,830 31,181 39,214 Distributions to participating securities (679 ) (153 ) (1,674 ) (527 ) Net income available to common shareholders — basic and diluted $ 8,681 $ 22,677 $ 29,507 $ 38,687 Weighted average number of common shares outstanding — basic and diluted 134,127 119,835 129,527 118,588 Earnings per common share: Basic $ 0.06 $ 0.19 $ 0.23 $ 0.33 Diluted $ 0.06 $ 0.19 $ 0.23 $ 0.33

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	The following are assets and liabilities measured at fair value on a recurring basis: Fair Value Measurements Total Level 1 Level 2 Level 3 September 30, 2019 (In thousands) Derivative financial instruments designated as cash flow hedges: Classified as liabilities in "Other liabilities, net" $ 27,577 — $ 27,577 — December 31, 2018 Derivative financial instruments designated as cash flow hedges: Classified as assets in "Other assets, net" $ 7,913 $ — $ 7,913 $ — Classified as liabilities in "Other liabilities, net" 1,723 — 1,723 — Derivative financial instruments not designated as cash flow hedges: Classified as assets in "Other assets, net" 2,470 — 2,470 —
Schedule of Financial Instruments and Liabilities as Reflected on Balance Sheet	As of September 30, 2019 and December 31, 2018 , 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, 2019 December 31, 2018 Carrying Amount (1) Fair Value Carrying Amount (1) Fair Value (In thousands) Financial liabilities: Mortgages payable $ 1,361,840 $ 1,404,849 $ 1,844,652 $ 1,870,078 Unsecured term loans 300,000 301,076 300,000 300,727 ______________________________________ ( 1)

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2019
Segment Reporting [Abstract]
Segment information	The following table reflects the reconciliation of net income attributable to common shareholders to consolidated NOI: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (In thousands) Net income attributable to common shareholders $ 9,360 $ 22,830 $ 31,181 $ 39,214 Add: Depreciation and amortization expense 46,862 46,603 141,576 143,880 General and administrative expense: Corporate and other 11,015 8,201 34,888 25,218 Third-party real estate services 29,809 20,754 86,585 64,552 Share-based compensation related to Formation Transaction and special equity awards 9,549 8,387 30,203 26,912 Transaction and other costs 2,059 4,126 9,928 12,134 Interest expense 10,583 18,979 40,864 56,263 Loss on extinguishment of debt — 79 1,889 4,536 Reduction of gain on bargain purchase — — — 7,606 Income tax expense (benefit) 432 (841 ) (689 ) (1,436 ) Net income attributable to redeemable noncontrolling 1,172 3,552 4,271 6,532 Less: Third-party real estate services, including reimbursements 34,587 23,788 91,765 72,278 Other income (1) 2,196 1,708 5,951 4,904 Income (loss) from unconsolidated real estate ventures, net (1,144 ) 13,484 647 15,418 Interest and other income (loss), net (640 ) 4,091 2,363 5,177 Gain on sale of real estate 8,088 11,938 47,121 45,789 Net loss attributable to noncontrolling interests — — — 127 Consolidated NOI $ 77,754 $ 77,661 $ 232,849 $ 241,718 __________________________ (1) Excludes parking income of $6.3 million and $6.4 million for the three months ended September 30, 2019 and 2018 , and $19.5 million and $19.3 million for the nine months ended September 30, 2019 and 2018 . Below 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, 2019 Commercial Multifamily Other Total (In thousands) Property rentals revenue $ 94,678 $ 28,946 $ 339 $ 123,963 Other property operating income 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 Three Months Ended September 30, 2018 Commercial Multifamily Other Total (In thousands) Property rentals revenue $ 99,011 $ 27,911 $ (342 ) $ 126,580 Other property operating income 6,244 94 29 6,367 Total property revenue 105,255 28,005 (313 ) 132,947 Property expense: Property operating 29,815 8,248 318 38,381 Real estate taxes 12,479 3,558 868 16,905 Total property expense 42,294 11,806 1,186 55,286 Consolidated NOI $ 62,961 $ 16,199 $ (1,499 ) $ 77,661 Nine Months Ended September 30, 2019 Commercial Multifamily Other Total (In thousands) Property rentals revenue $ 285,551 $ 86,069 $ (5,918 ) $ 365,702 Other property operating income 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 Nine Months Ended September 30, 2018 Commercial Multifamily Other Total (In thousands) Property rentals revenue $ 304,756 $ 80,452 $ (809 ) $ 384,399 Other property operating income 18,981 281 84 19,346 Total property revenue 323,737 80,733 (725 ) 403,745 Property expense: Property operating 85,862 23,247 (1,106 ) 108,003 Real estate taxes 39,477 10,721 3,826 54,024 Total property expense 125,339 33,968 2,720 162,027 Consolidated NOI $ 198,398 $ 46,765 $ (3,445 ) $ 241,718 The following is a summary of certain balance sheet data by segment: Commercial Multifamily Other Total September 30, 2019 (In thousands) Real estate, at cost $ 3,695,072 $ 1,798,854 $ 376,664 $ 5,870,590 Investments in unconsolidated real estate ventures 174,486 108,625 37,809 320,920 Total assets (1) 3,512,802 1,663,800 845,662 6,022,264 December 31, 2018 Real estate, at cost $ 3,634,472 $ 1,656,974 $ 501,288 $ 5,792,734 Investments in unconsolidated real estate ventures 177,173 109,232 36,473 322,878 Total assets (1) 3,707,255 1,528,177 761,853 5,997,285 __________________________ (1)

Organization and Basis of Pre_3

Organization and Basis of Presentation - Narrative (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019USD ($)ft²building_unitproperties	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)ft²building_unitproperties	Sep. 30, 2018USD ($)
Real Estate Properties [Line Items]
Number of Real Estate Properties | properties	61		61
Parking Income | $	$ (6.3)	$ (6.4)	$ (19.5)	$ (19.3)
Asset under Construction
Real Estate Properties [Line Items]
Number of Real Estate Properties | properties	8		8
Future Development
Real Estate Properties [Line Items]
Number of Real Estate Properties | properties	40		40
Area of real estate property (in square feet) | ft²	21,900,000		21,900,000
Commercial Real Estate [Member]
Real Estate Properties [Line Items]
Number of Real Estate Properties | properties	45		45
Area of real estate property (in square feet) | ft²	12,700,000		12,700,000
Commercial Real Estate [Member] | Asset under Construction
Real Estate Properties [Line Items]
Number of Real Estate Properties | properties	4		4
Area of real estate property (in square feet) | ft²	943,000		943,000
Multifamily
Real Estate Properties [Line Items]
Number of Real Estate Properties | properties	16		16
Number of Units in Real Estate Property | building_unit	6,321		6,321
Multifamily | Asset under Construction
Real Estate Properties [Line Items]
Number of Real Estate Properties | properties	4		4
Number of Units in Real Estate Property | building_unit	1,476		1,476
Wholly Owned Properties | Future Development
Real Estate Properties [Line Items]
Area of real estate property (in square feet) | ft²	18,700,000		18,700,000
Wholly Owned Properties | Commercial Real Estate [Member]
Real Estate Properties [Line Items]
Area of real estate property (in square feet) | ft²	11,000,000		11,000,000
Wholly Owned Properties | Commercial Real Estate [Member] | Asset under Construction
Real Estate Properties [Line Items]
Area of real estate property (in square feet) | ft²	821,000		821,000
Wholly Owned Properties | Multifamily
Real Estate Properties [Line Items]
Number of Units in Real Estate Property | building_unit	4,537		4,537
Wholly Owned Properties | Multifamily | Asset under Construction
Real Estate Properties [Line Items]
Area of real estate property (in square feet) | ft²	1,298		1,298
Restatement Adjustment [Member]
Real Estate Properties [Line Items]
Parking Income | $		6.4		19.3
Reimbursements from Tenants | $		9.7		28.7
Cost of Other Property Operating Expense | $		$ 4.2		$ 12.5
JBG Smith, LP
Real Estate Properties [Line Items]
Ownership interest by parent	89.80%		89.80%

Summary of Significant Accoun_4

Summary of Significant Accounting Policies Narratives (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Jan. 01, 2019	Dec. 31, 2018	Dec. 31, 2017
Deferred Costs, Leasing, Net		$ 1,500,000		$ 4,300,000
Land and Land Improvements							$ 16,000,000
Operating Lease, Weighted Average Discount Rate, Percent	5.30%		5.30%
Operating right-of-use assets, net (1)	$ 31,795,000		$ 31,795,000		$ 35,300,000	$ 0
Ground lease deferred rent payable	0		0		3,500,000	3,510,000
Other identified intangible assets, net	50,395,000		50,395,000		767,000	55,469,000
Prepaid expenses	$ 20,011,000		$ 20,011,000		$ 140,000	$ 6,482,000
Finance Lease, Weighted Average Discount Rate, Percent	5.80%		5.80%
Operating Lease, Weighted Average Remaining Lease Term	20 years 8 months 12 days		20 years 8 months 12 days
Finance Lease, Weighted Average Remaining Lease Term	7 years 3 months 18 days		7 years 3 months 18 days
Fixed Operating and Finance Lease, Cost	$ 662,000		$ 1,900,000
Variable operating lease costs	$ 437,000		$ 1,300,000

Summary of Significant Accoun_5

Summary of Significant Accounting Policies Property Rentals (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Accounting Policies [Abstract]
Property rentals - fixed	$ 114,538	$ 342,268
Property rentals - variable	9,425	23,434
Property rentals - total	$ 123,963	$ 365,702

Summary of Significant Accoun_6

Summary of Significant Accounting Policies Operating Lease, Payments to be Recevied (Details) $ in Thousands	Sep. 30, 2019USD ($)
Lessor, Lease, Description [Line Items]
2019	$ 101,929
2020	367,750
2021	307,251
2022	273,711
2023	235,298
2024	208,243
Thereafter	$ 1,109,914

Summary of Significant Accoun_7

Summary of Significant Accounting Policies Future Minimum Payments Receivable (Details) $ in Thousands	Dec. 31, 2018USD ($)
2019	$ 377,427
2020	321,205
2021	287,463
2022	256,352
2023	215,203
Thereafter	$ 1,188,767

Summary of Significant Accoun_8

Summary of Significant Accounting Policies Lessee, Lease Liability, Maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Operating Leases [Line Items]
2019 (1)	$ 1,573
2020	6,272
2021	6,201
2022	5,257
2023	2,000
2024	2,061
Thereafter	36,579
Total future minimum lease payments	59,943
Imputed interest	(25,403)
Lease liabilities related to operating right-of-use assets (1)	34,540		$ 0
2019	266
2020	1,073
2021	1,095
2022	1,117
2023	1,139
2024	1,162
Thereafter	15,977
Total future minimum lease payments	21,829
Imputed interest	(6,228)
Finance lease liability	15,601		$ 15,704
Other Liabilities [Member]
Operating Leases [Line Items]
Lease liabilities related to operating right-of-use assets (1)	34,500	$ 37,900
Finance lease liability	$ 15,600

Summary of Significant Accoun_9

Summary of Significant Accounting Policies Future Minimum Rental Payments (Details) $ in Thousands	Dec. 31, 2018USD ($)
Accounting Policies [Abstract]
2019	$ 13,991
2020	13,710
2021	13,395
2022	12,554
2023	9,489
Thereafter	55,780
Total	$ 118,919

Acquisition, Disposals and As_3

Acquisition, Disposals and Assets Held for Sale Acquisition (Details) - Multifamily $ in Millions	9 Months Ended
	Sep. 30, 2019USD ($)ft²building_unit
Number of Units in Real Estate Property	6,321
F1RST Residences [Member] | Washington, D.C. [Member]
Number of Units in Real Estate Property	325
Area of real estate property (in square feet) | ft²	21,000
Payments to Acquire Businesses, Gross | $	$ 160.5
Occupancy, Percentage	95.40%

Acquisition, Disposals and As_4

Acquisition, Disposals and Assets Held for Sale Dispositions and Assets Held for Sale (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019USD ($)ft²	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)ft²	Sep. 30, 2018USD ($)	Dec. 31, 2018USD ($)ft²
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Sale of Property Held-for-sale			$ 157,950
Proceeds from sale of real estate			157,810
Gain on sale of real estate	$ 8,088	$ 11,938	47,121	$ 45,789
Assets held for sale	168,820		168,820		$ 78,981
Liabilities related to assets held for sale	$ 66		$ 66		$ 3,717
Commerce Executive / Commerce Metro Land, 1600 K Street [Domain]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Area of real estate property (in square feet) | ft²	471,215		471,215
National Landing, Virginia [Member] | Pen Place - Land Parcel [Member] | Other
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets held for sale	$ 74,107		$ 74,107
Liabilities related to assets held for sale	0		0
National Landing, Virginia [Member] | Metropolitan 6, 7 and 8 [Member] | Other
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets held for sale	94,713		94,713
Liabilities related to assets held for sale	66		66
National Landing, Virginia [Member] | Penn Place and Met 6, 7 and 8 [Member] | Other
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Sale of Property Held-for-sale	$ 293,900		$ 293,900
Reston, Virginia [Member] | Commerce Executive/Commerce Metro Land [Member] | Commercial Segment [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Area of real estate property (in square feet) | ft²	388,562		388,562		388,562
Proceeds from Sale of Property Held-for-sale			$ 114,950
Proceeds from sale of real estate			117,676
Gain on sale of real estate			39,033
Assets held for sale					$ 78,981
Liabilities related to assets held for sale					$ 3,717
Proceeds from Sale of Real Estate Held-for-Investment, Reimbursements			$ 4,000
Washington, D.C. [Member] | 1600 K Street [Member] | Commercial Segment [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Area of real estate property (in square feet) | ft²	82,653		82,653
Proceeds from Sale of Property Held-for-sale			$ 43,000
Proceeds from sale of real estate			40,134
Gain on sale of real estate			$ 8,088
Future Development
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Area of real estate property (in square feet) | ft²	21,900,000		21,900,000
Future Development | Commerce Executive/Commerce Metro Land [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Area of real estate property (in square feet) | ft²	894,000		894,000
Future Development | Penn Place and Met 6, 7 and 8 [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Area of real estate property (in square feet) | ft²	4,100,000		4,100,000

Investments in and Advances t_3

Investments in and Advances to Unconsolidated Real Estate Ventures - Summary of Composition of Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Schedule of Equity Method Investments [Line Items]
Total investments in and advances to unconsolidated real estate ventures	$ 320,920	$ 322,878
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	$ 101,465	97,521
Landmark
Schedule of Equity Method Investments [Line Items]
Total investments in unconsolidated real estate ventures	78,979	84,320
CBREI Venture
Schedule of Equity Method Investments [Line Items]
Total investments in unconsolidated real estate ventures	$ 69,699	73,776
Berkshire Group
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	50.00%
Total investments in unconsolidated real estate ventures	$ 45,974	43,937
Brandywine
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	30.00%
Total investments in unconsolidated real estate ventures	$ 13,895	13,777
CIM/PacLife
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	16.70%
Total investments in unconsolidated real estate ventures	$ 10,614	9,339
Other
Schedule of Equity Method Investments [Line Items]
Total investments in unconsolidated real estate ventures	$ 294	$ 208
Minimum | Landmark
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	1.80%
Minimum | CBREI Venture
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	5.00%
Maximum | Landmark
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	49.00%
Maximum | CBREI Venture
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	64.00%

Investments in and Advances t_4

Investments in and Advances to Unconsolidated Real Estate Ventures - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Schedule of Equity Method Investments [Line Items]
Income (Loss) from Equity Method Investments	$ (1,144,000)	$ 13,484,000	$ 647,000	$ 15,418,000
1101 17th Street [Member]
Schedule of Equity Method Investments [Line Items]
Real Estate Investments, Unconsolidated Real Estate and Other Joint Ventures, Excluding Advances	$ 0		0		$ 0
Income (Loss) from Equity Method Investments		$ 890,000	$ 6,400,000	890,000
Investments in Unconsolidated Real Estate Ventures [Member] | 1101 17th Street [Member]
Schedule of Equity Method Investments [Line Items]
Income (Loss) from Equity Method Investments				$ 5,400,000

Investments in and Advances t_5

Investments in and Advances to Unconsolidated Real Estate Ventures - Summary of Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Equity Method Investments and Joint Ventures [Abstract]
Variable rate, weighted average interest rate	4.65%
Variable rate	$ 627,787	$ 461,704
Fixed rate, weighted average interest rate	3.97%
Fixed rate	$ 548,591	665,662
Unconsolidated real estate ventures - mortgages payable	1,176,378	1,127,366
Unamortized deferred financing costs	(1,905)	(1,998)
Unconsolidated real estate ventures - mortgages payable, net	$ 1,174,473	$ 1,125,368

Investments in and Advances t_6

Investments in and Advances to Unconsolidated Real Estate Ventures - Condensed Combined Financial Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Jan. 01, 2019	Dec. 31, 2018
Equity Method Investment, Summarized Financial Information, Assets, Operating Leases, Right of Use Assets					$ 52,400
Operating Lease, Liability					$ 44,100
Combined balance sheet information:
Real estate, net	$ 2,118,483		$ 2,118,483			$ 2,050,985
Other assets, net	192,128		192,128			169,264
Total assets	2,310,611		2,310,611			2,220,249
Borrowings, net	1,174,473		1,174,473			1,125,368
Other liabilities, net	138,737		138,737			94,845
Total liabilities	1,313,210		1,313,210			1,220,213
Total equity	997,401		997,401			1,000,036
Total liabilities and equity	2,310,611		2,310,611			$ 2,220,249
Combined income statement information:
Total revenue	65,110	$ 76,247	199,897	$ 236,938
Operating income	10,925	6,861	21,034	23,719
Net loss	$ (3,602)	$ (6,970)	$ (20,289)	$ (12,159)

Variable Interest Entities (Det

Variable Interest Entities (Details) $ in Millions	Sep. 30, 2019USD ($)properties	Dec. 31, 2018USD ($)
Variable Interest Entity [Line Items]
Number of Real Estate Properties | properties	61
Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Assets	$ 235.1	$ 232.8
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Assets	122.1	94.8
Liabilities	$ 17	$ 43.4
Number of Real Estate Properties	1	2

Other Assets, Net Summary of Ot

Other Assets, Net Summary of Other Assets, Net (Details) - USD ($)	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Deferred leasing costs, net	$ 143,590,000		$ 129,601,000
Lease intangible assets, net	24,084,000		34,390,000
Other identified intangible assets, net	50,395,000	$ 767,000	55,469,000
Operating right-of-use assets, net (1)	31,795,000	35,300,000	0
Prepaid expenses	20,011,000	$ 140,000	6,482,000
Deferred financing costs on credit facility, net	3,392,000		4,806,000
Deposits	12,135,000		3,633,000
Derivative agreements, at fair value	0		10,383,000
Other	16,358,000		20,230,000
Total other assets, net	$ 301,760,000		$ 264,994,000

Debt - Schedule of Mortgages Pa

Debt - Schedule of Mortgages Payable (Details) - Mortgages payable - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Variable interest rate	3.67%
Variable rate amount	$ 14,000	$ 308,918
Fixed interest rate	4.20%
Fixed rate amount	$ 1,347,840	1,535,734
Mortgages payable	1,361,840	1,844,652
Unamortized deferred financing costs and premium/ discount, net	(3,269)	(6,271)
Mortgages payable, net	$ 1,358,571	$ 1,838,381

Debt - Narrative (Details)

Debt - Narrative (Details) $ in Thousands	Jul. 17, 2019	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Dec. 31, 2018USD ($)
Line of Credit Facility [Line Items]
Loss on extinguishment of debt		$ 0	$ (79)	$ (1,889)	$ (4,536)
Mortgages payable
Line of Credit Facility [Line Items]
Net carrying value of real estate collateralizing the mortgages payable		1,800,000		1,800,000		$ 2,300,000
Repayments of Secured Debt				475,100
Derivative, notional amount		1,100,000		1,100,000		$ 1,300,000
Line of credit
Line of Credit Facility [Line Items]
Credit facility, maximum borrowing capacity		1,400,000		1,400,000
Line of credit | Revolving credit facility
Line of Credit Facility [Line Items]
Credit facility, maximum borrowing capacity		$ 1,000,000		$ 1,000,000
Debt Instrument, Number Of Term Extension Options		2		2
Line of credit | Tranche A-1 Term Loan
Line of Credit Facility [Line Items]
Derivative, notional amount		$ 100,000		$ 100,000
Credit facility, maximum borrowing capacity		200,000		200,000
Line of credit | Tranche A-2 Term Loan
Line of Credit Facility [Line Items]
Derivative, notional amount		137,600		137,600
Credit facility, maximum borrowing capacity		$ 200,000		$ 200,000
London Interbank Offered Rate (LIBOR) [Member] | Line of credit | Tranche A-2 Term Loan
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate, Reduction	40.00%
Debt Instrument, Basis Spread on Variable Rate	1.15%			1.55%
Other Expense [Member]
Line of Credit Facility [Line Items]
Loss on extinguishment of debt				$ 1,900

Debt - Summary of Amounts Outst

Debt - Summary of Amounts Outstanding under the Credit Facility (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Line of Credit Facility [Line Items]
Debt Issuance Costs, Line of Credit Arrangements, Net	$ 3,392	$ 4,806
Tranche A-1 and A-2 Loans [Member]
Line of Credit Facility [Line Items]
Debt, gross	300,000	300,000
Unamortized deferred financing costs, net	(2,876)	(2,871)
Mortgages payable, net	$ 297,124	297,129
Line of credit | Revolving credit facility
Line of Credit Facility [Line Items]
Interest Rate (1)	3.12%
Mortgages payable, net	$ 0	0
Letters of Credit Outstanding, Amount	$ 2,400	5,700
Line of Credit Facility, Commitment Fee Percentage	0.15%
Line of credit | Tranche A-1 Term Loan
Line of Credit Facility [Line Items]
Interest Rate (1)	3.32%
Debt, gross	$ 100,000	100,000
Derivative, Notional Amount	$ 100,000
Line of credit | Tranche A-2 Term Loan
Line of Credit Facility [Line Items]
Interest Rate (1)	3.82%
Debt, gross	$ 200,000	$ 200,000
Derivative, Notional Amount	$ 137,600

Other Liabilities, Net Summary

Other Liabilities, Net Summary of Other Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Schedule of Other Liabilities [Line Items]
Lease intangible liabilities, net	$ 12,243		$ 14,098
Prepaid rent	25,810		21,998
Lease assumption liabilities	21,856		23,105
Lease incentive liabilities	26,317		9,317
Lease liabilities related to operating right-of-use assets (1)	34,540		0
Finance lease liability	15,601		15,704
Security deposits	16,573		17,696
Environmental liabilities	17,898		17,898
Ground lease deferred rent payable	0	$ 3,500	3,510
Deferred tax liability	6,250		6,878
Dividends payable	0		45,193
Derivative agreements, at fair value	27,577		1,723
Other	1,040		4,486
Total other liabilities, net	$ 205,705		$ 181,606

Redeemable Noncontrolling Int_3

Redeemable Noncontrolling Interests - Narrative (Details) shares in Millions	9 Months Ended
	Sep. 30, 2019shares
Consolidated Real Estate Venture
Noncontrolling Interest [Line Items]
Ownership interest by parent	94.20%
Ownership interest by parent, threshold for capital contributions to cease	97.00%
OP Units [Member]
Noncontrolling Interest [Line Items]
Common shares and OP Units issued in consideration	15.2
Conversion of common limited partnership units to common shares	1.7
OP Units [Member] | JBG Smith, LP
Noncontrolling Interest [Line Items]
Ownership interest by parent	10.20%
Minimum
Noncontrolling Interest [Line Items]
Redemption period	2 years
Maximum
Noncontrolling Interest [Line Items]
Redemption period	7 years

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, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Temporary Equity
Beginning Balance	$ 574,228	$ 665,623	$ 558,140	$ 609,129
Fair value of OP Unit redemptions	0	(109,208)	(57,318)	(109,208)
Long-term incentive partnership units (LTIP Units) issued in lieu of cash bonuses (1)			3,954	0
Net income (loss) attributable to redeemable noncontrolling interests	1,172	3,552	4,271	6,532
Other comprehensive income	(803)	696	(3,689)	3,406
Temporary Equity, Contributions (Distributions)	(3,831)	(4,106)	(7,670)	(8,263)
Share-based compensation expense	14,320	12,298	45,937	39,376
Adjustment to redemption value	1,446	(6,537)	42,907	21,346
Ending Balance	586,532	562,318	586,532	562,318
JBG Smith, LP
Temporary Equity
Beginning Balance	568,242	659,716	552,159	603,717
Fair value of OP Unit redemptions	0	(109,208)	(57,318)	(109,208)
Long-term incentive partnership units (LTIP Units) issued in lieu of cash bonuses (1)			3,954	0
Net income (loss) attributable to redeemable noncontrolling interests	1,172	3,552	4,266	6,537
Other comprehensive income	(803)	696	(3,689)	3,406
Temporary Equity, Contributions (Distributions)	(3,831)	(4,106)	(7,670)	(8,763)
Share-based compensation expense	14,320	12,298	45,937	39,376
Adjustment to redemption value	1,446	(6,537)	42,907	21,346
Ending Balance	580,546	556,411	580,546	556,411
Consolidated Real Estate Venture
Temporary Equity
Beginning Balance	5,986	5,907	5,981	5,412
Fair value of OP Unit redemptions	0	0	0	0
Long-term incentive partnership units (LTIP Units) issued in lieu of cash bonuses (1)			0	0
Net income (loss) attributable to redeemable noncontrolling interests	0	0	5	(5)
Other comprehensive income	0	0	0	0
Temporary Equity, Contributions (Distributions)	0	0	0	500
Share-based compensation expense	0	0	0	0
Adjustment to redemption value	0	0	0	0
Ending Balance	$ 5,986	$ 5,907	$ 5,986	$ 5,907

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
	May 31, 2019	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Compensation expense recognition period (in years)		2 years 3 months 18 days
Management [Member] | Time-Based LTIP Units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Equity grants (in shares)		351,982
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights		P4Y
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage		25.00%
Compensation expense recognition period (in years)		4 years
Fair value of awards on grant date		$ 12.1
Weighted Average Grant-Date Fair Value
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value		$ 34.26
Management [Member] | LTIP Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Equity grants (in shares)		91,636
Fair value of awards on grant date		$ 3.1
Weighted Average Grant-Date Fair Value
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value		$ 34.21
Director [Member] | LTIP Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Equity grants (in shares)	50,159
Fair value of awards on grant date	$ 1.8
Measurement Input, Price Volatility [Member] | LTIP and Time-Based LTIP Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Minimum		18.00%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Maximum		24.00%
Measurement Input, Risk Free Interest Rate [Member] | LTIP and Time-Based LTIP Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate, Minimum		2.30%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate		2.60%
Minimum | Measurement Input, Expected Term [Member] | LTIP and Time-Based LTIP Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term		2 years
Maximum | Measurement Input, Expected Term [Member] | LTIP and Time-Based LTIP Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term		3 years

Share-Based Payments - Performa

Share-Based Payments - Performance-Based LTIP Units (Details) $ / shares in Units, $ in Millions	9 Months Ended
	Sep. 30, 2019USD ($)$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense recognition period (in years)	2 years 3 months 18 days
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense recognition period (in years)	4 years
Equity grants (in shares) | shares	478,411
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years
Fair value of awards on grant date | $	$ 9.3
Weighted Average Grant-Date Fair Value
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value | $ / shares	$ 19.49
Performance Shares [Member] | Share-based Compensation Award, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage	50.00%
Performance Shares [Member] | Share-based Compensation Award, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage	50.00%
Measurement Input, Price Volatility [Member] | Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Minimum	19.00%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Maximum	23.00%
Measurement Input, Risk Free Interest Rate [Member] | Performance Shares [Member]
Weighted Average Grant-Date Fair Value
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate, Minimum	2.30%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate, Maximum	2.60%
Minimum | Measurement Input, Expected Dividend Rate [Member] | Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate	2.30%
Maximum | Measurement Input, Expected Dividend Rate [Member] | Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate	2.50%

Share-Based Payments - Employee

Share-Based Payments - Employee Stock Purchase Plan (Details) - USD ($)	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Stock Issued During Period, Shares, Employee Stock Purchase Plans	0	26,000
Employee Stock [Member]
Stock Issued During Period, Shares, Employee Stock Purchase Plans		25,575
Proceeds from Stock Plans		$ 747,000
Measurement Input, Price Volatility [Member] | Employee Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Weighted Average Volatility Rate		28.00%
Measurement Input, Expected Dividend Rate [Member] | Employee Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate		2.60%
Measurement Input, Risk Free Interest Rate [Member] | Employee Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate		2.40%
Measurement Input, Expected Term [Member] | Employee Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term		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, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation related to Formation Transaction and special equity awards	$ 9,549	$ 8,387	$ 30,203	$ 26,912
Allocated Share-based Compensation Expense, Before Capitalization	15,723	13,287	49,380	42,069
Less amount capitalized	(406)	(873)	(1,948)	(2,379)
Share-based compensation expense	15,317	12,414	47,432	39,690
Total unrecognized compensation expense	94,700		$ 94,700
Compensation expense recognition period (in years)			2 years 3 months 18 days
Time-Based LTIP Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	2,755	2,520	$ 8,529	7,772
Performance-Based LTIP Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	2,016	1,391	$ 6,205	3,898
Compensation expense recognition period (in years)			4 years
Long-Term Incentive Partnership Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	0	0	$ 1,000	794
Other Equity Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	1,403	989	3,443	2,693
Share-based compensation expense - other
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	6,174	4,900	19,177	15,157
Formation Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	1,227	1,375	4,116	4,192
OP Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	6,747	6,943	21,491	22,512
LTIP Units Related to Formation Transaction And Other [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	117	69	340	208
Special Performance-Based LTIP Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	654	0	1,938	0
Special Time-Based LTIP Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	804	0	2,318	0
Share-based compensation related to Formation Transaction
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation related to Formation Transaction and special equity awards	$ 9,549	$ 8,387	$ 30,203	$ 26,912

Interest Expense Interest Exp_3

Interest Expense Interest Expense (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Interest expense	$ 18,141,000	$ 23,465,000	$ 61,449,000	$ 69,024,000
Amortization of deferred financing costs	698,000	1,043,000	2,576,000	3,501,000
Net unrealized loss (gain) on derivative financial instruments not designated as cash flow hedges	2,000	287,000	50,000	(1,264,000)
Derivative, Gain (Loss) on Derivative, Net	0	(135,000)	0	(135,000)
Capitalized interest	(8,258,000)	(5,681,000)	(23,211,000)	(14,863,000)
Interest Expense	$ 10,583,000	$ 18,979,000	$ 40,864,000	$ 56,263,000

Shareholders' Equity and Earn_2

Shareholders' Equity and Earnings Per Common Share Narrative (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	1 Months Ended	9 Months Ended
	Apr. 30, 2019	Sep. 30, 2019	Sep. 30, 2018	Apr. 15, 2019	Dec. 31, 2018
Earnings Per Share [Abstract]
Common Stock, Shares, Issued		134,127		11,500	120,937
Excess Stock, Shares Issued				1,500
Shares Issued, Price Per Share				$ 42
Proceeds from the issuance of common stock, net of issuance costs	$ 472,800	$ 473,527	$ 0

Shareholders' Equity and Earn_3

Shareholders' Equity and Earnings Per Common Share Schedule of Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share [Abstract]
Net income	$ 10,532	$ 26,382	$ 35,452	$ 45,619
Net (income) loss attributable to redeemable noncontrolling interests	(1,172)	(3,552)	(4,271)	(6,532)
Net loss attributable to noncontrolling interests	0	0	0	127
Net income (loss) attributable to common shareholders	(9,360)	(22,830)	(31,181)	(39,214)
Distributions to participating securities	(679)	(153)	(1,674)	(527)
Net income available to common shareholders — basic and diluted	$ 8,681	$ 22,677	$ 29,507	$ 38,687
Weighted average number of common shares outstanding — basic and diluted	134,127	119,835	129,527	118,588
Earnings (loss) per common share:
Earnings Per Share, Basic	$ 0.06	$ 0.19	$ 0.23	$ 0.33
Earnings Per Share, Diluted	$ 0.06	$ 0.19	$ 0.23	$ 0.33

Shareholders' Equity and Earn_4

Shareholders' Equity and Earnings Per Common Share Antidilutive Securities Excluded (Details) - shares shares in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	4.7	3.9	4.7	3.8

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Net unrealized gain (loss) on derivative designated as cash flow hedge			$ (27,700,000)		$ 8,300,000
Loss expected to be reclassified into interest expense within the next 12 months			6,300,000
Net unrealized loss (gain) on derivative financial instruments not designated as cash flow hedges	$ 2,000	$ 287,000	$ 50,000	$ (1,264,000)

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis (Details) - Interest rate swap and caps - Recurring - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Other Assets, Net | Designated as Hedging Instrument
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Classified as assets in Other assets, net		$ 7,913
Other Assets, Net | Designated as Hedging Instrument | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Classified as assets in Other assets, net		0
Other Assets, Net | 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		7,913
Other Assets, Net | Designated as Hedging Instrument | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Classified as assets in Other assets, net		0
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		2,470
Other Assets, Net | Not Designated as Hedging Instrument | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Classified as assets in Other assets, net		0
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		2,470
Other Assets, Net | Not Designated as Hedging Instrument | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Classified as assets in Other assets, net		0
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	$ 27,577	1,723
Other Liabilities, Net | Designated as Hedging Instrument | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Classified as liabilities in Other liabilities, net	0	0
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	27,577	1,723
Other Liabilities, Net | Designated as Hedging Instrument | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Classified as liabilities in Other liabilities, net	$ 0	$ 0

Fair Value Measurements - Finan

Fair Value Measurements - Financial Assets and Liabilities Not Measured at Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Mortgages payable | Carrying Amount
Financial liabilities:
Financial liabilities	$ 1,361,840	$ 1,844,652
Mortgages payable | Fair Value
Financial liabilities:
Financial liabilities	1,404,849	1,870,078
Unsecured term loans | Carrying Amount
Financial liabilities:
Financial liabilities	300,000	300,000
Unsecured term loans | Fair Value
Financial liabilities:
Financial liabilities	$ 301,076	$ 300,727

Segment Information - Narrative

Segment Information - Narrative (Details) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019USD ($)segment	Sep. 30, 2019USD ($)segment	Dec. 31, 2018USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment	3	3
Other assets, net	$ 301,760	$ 301,760	$ 264,994
Third-Party Real Estate Services Segment
Segment Reporting Information [Line Items]
Other assets, net	$ 33,300	$ 33,300	$ 38,600

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, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Business Acquisition [Line Items]
Net income (loss) attributable to common shareholders	$ 9,360	$ 22,830	$ 31,181	$ 39,214
Depreciation and amortization	46,862	46,603	141,576	143,880
Corporate and other	11,015	8,201	34,888	25,218
Third-party real estate services	29,809	20,754	86,585	64,552
Share-based compensation related to Formation Transaction and special equity awards	9,549	8,387	30,203	26,912
Transaction and other costs	2,059	4,126	9,928	12,134
Interest expense	10,583	18,979	40,864	56,263
Loss on extinguishment of debt	0	79	1,889	4,536
Reduction of gain on bargain purchase	0	0	0	(7,606)
Income tax benefit	432	(841)	(689)	(1,436)
Net (income) loss attributable to redeemable noncontrolling interests	1,172	3,552	4,271	6,532
Third-party real estate services, including reimbursements	34,587	23,788	91,765	72,278
Other Income, Excluding Parking Income	2,196	1,708	5,951	4,904
Income (loss) from unconsolidated real estate ventures, net	(1,144)	13,484	647	15,418
Interest and other income (loss), net	(640)	4,091	2,363	5,177
Gain on sale of real estate	8,088	11,938	47,121	45,789
Net loss attributable to noncontrolling interests	0	0	0	127
Consolidated NOI	77,754	77,661	232,849	241,718
Parking Income	$ 6,300	$ 6,400	$ 19,500	$ 19,300

Segment Information - Summary o

Segment Information - Summary of NOI by Segment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting Information [Line Items]
Operating Leases, Income Statement, Lease Revenue		$ 126,580		$ 384,399
Operating Lease, Lease Income	$ 123,963		$ 365,702
Direct Costs of Leased and Rented Property or Equipment	35,800	38,381	100,087	108,003
Real estate taxes	16,740	16,905	52,241	54,024
Operating Segments
Segment Reporting Information [Line Items]
Operating Leases, Income Statement, Lease Revenue		126,580		384,399
Operating Lease, Lease Income	123,963		365,702
Other property operating income	6,331	6,367	19,475	19,346
Total rental revenue	130,294	132,947	385,177	403,745
Direct Costs of Leased and Rented Property or Equipment	35,800	38,381	100,087	108,003
Real estate taxes	16,740	16,905	52,241	54,024
Total rental expense	52,540	55,286	152,328	162,027
Consolidated NOI	77,754	77,661	232,849	241,718
Operating Segments | Commercial Segment [Member]
Segment Reporting Information [Line Items]
Operating Leases, Income Statement, Lease Revenue		99,011		304,756
Operating Lease, Lease Income	94,678		285,551
Other property operating income	6,237	6,244	19,212	18,981
Total rental revenue	100,915	105,255	304,763	323,737
Direct Costs of Leased and Rented Property or Equipment	27,200	29,815	84,089	85,862
Real estate taxes	12,004	12,479	37,257	39,477
Total rental expense	39,204	42,294	121,346	125,339
Consolidated NOI	61,711	62,961	183,417	198,398
Operating Segments | Multifamily
Segment Reporting Information [Line Items]
Operating Leases, Income Statement, Lease Revenue		27,911		80,452
Operating Lease, Lease Income	28,946		86,069
Other property operating income	94	94	263	281
Total rental revenue	29,040	28,005	86,332	80,733
Direct Costs of Leased and Rented Property or Equipment	9,490	8,248	25,662	23,247
Real estate taxes	3,552	3,558	11,243	10,721
Total rental expense	13,042	11,806	36,905	33,968
Consolidated NOI	15,998	16,199	49,427	46,765
Operating Segments | Other
Segment Reporting Information [Line Items]
Operating Leases, Income Statement, Lease Revenue		(342)		(809)
Operating Lease, Lease Income	339		(5,918)
Other property operating income	0	29	0	84
Total rental revenue	339	(313)	(5,918)	(725)
Direct Costs of Leased and Rented Property or Equipment	(890)	318	(9,664)	(1,106)
Real estate taxes	1,184	868	3,741	3,826
Total rental expense	294	1,186	(5,923)	2,720
Consolidated NOI	$ 45	$ (1,499)	$ 5	$ (3,445)

Segment Information - Summary_2

Segment Information - Summary of Certain Balance Sheet Data by Segment (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Real estate, at cost	$ 5,870,590	$ 5,792,734
Investments in and advances to unconsolidated real estate ventures	320,920	322,878
Total assets (1)	6,022,264	5,997,285
Operating Segments | Commercial Segment [Member]
Segment Reporting Information [Line Items]
Real estate, at cost	3,695,072	3,634,472
Investments in and advances to unconsolidated real estate ventures	174,486	177,173
Total assets (1)	3,512,802	3,707,255
Operating Segments | Multifamily
Segment Reporting Information [Line Items]
Real estate, at cost	1,798,854	1,656,974
Investments in and advances to unconsolidated real estate ventures	108,625	109,232
Total assets (1)	1,663,800	1,528,177
Operating Segments | Other
Segment Reporting Information [Line Items]
Real estate, at cost	376,664	501,288
Investments in and advances to unconsolidated real estate ventures	37,809	36,473
Total assets (1)	$ 845,662	$ 761,853

Commitments and Contingencies -

Commitments and Contingencies - Narrative (Details) - USD ($)	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Real Estate Properties [Line Items]
General liability insurance limit	$ 200,000,000
Property and rental value insurance coverage limit	2,000,000,000
Terrorist acts insurance coverage limit	2,000,000,000
Purchase obligation	283,800,000
Environmental liabilities	17,898,000	$ 17,898,000
Additional capital funding committed amount	47,100,000
Consolidated Properties
Real Estate Properties [Line Items]
Purchase obligation	238,000,000
Principal payment guarantees	8,300,000
Unconsolidated Properties
Real Estate Properties [Line Items]
Purchase obligation	45,700,000
Principal payment guarantees	$ 0
Minimum
Real Estate Properties [Line Items]
Commitment amortization period	2 years
Maximum
Real Estate Properties [Line Items]
Commitment amortization period	3 years

Transactions with Vornado and_2

Transactions with Vornado and Related Parties (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Related Party Transaction [Line Items]
Qualified Affordable Housing Project Investments, Total Capital Commitments	$ 93,700,000		$ 93,700,000
Third-party real estate services, including reimbursements	34,587,000	$ 23,788,000	91,765,000	$ 72,278,000
Corporate and other	11,015,000	8,201,000	34,888,000	25,218,000
Affiliated Entity [Member] | Washington Housing Initiative [Member]
Related Party Transaction [Line Items]
Qualified Affordable Housing Project Investments, Commitment	9,100,000		9,100,000
Affiliated Entity [Member] | Legacy JBG Funds [Member]
Related Party Transaction [Line Items]
Corporate and other	1,300,000	1,200,000	3,800,000	3,600,000
Affiliated Entity [Member] | Separation and Combination transaction | Vornado Realty Trust [Member]
Related Party Transaction [Line Items]
Expenses from related parties		931,000		3,200,000
Revenue from related parties	536,000	507,000	1,500,000	1,600,000
Affiliated Entity [Member] | Supervisory Services of Properties [Member] | BMS
Related Party Transaction [Line Items]
Related party transaction amount	5,500,000	5,400,000	16,100,000	15,500,000
Affiliated Entity [Member] | Fees from Legacy JBG Funds and Washington Housing Initiative [Member] | Legacy JBG Funds and Washington Housing Initiative [Member]
Related Party Transaction [Line Items]
Third-party real estate services, including reimbursements	10,200,000		28,600,000
Accounts Receivable, Related Parties	$ 6,900,000		$ 6,900,000
Affiliated Entity [Member] | Fees from Legacy JBG Funds | Legacy JBG Funds [Member]
Related Party Transaction [Line Items]
Third-party real estate services, including reimbursements		$ 8,700,000		$ 25,600,000
Accounts Receivable, Related Parties					$ 3,600,000

Subsequent Events (Details)

Subsequent Events (Details) - $ / shares	1 Months Ended	3 Months Ended		9 Months Ended
	Oct. 31, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
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