Common Shares Issued During Period in Connection with Redemption of OP Units

No definition available.

Name:	jbgs_CommonSharesIssuedDuringPeriodinConnectionwithRedemptionofOPUnits
Namespace Prefix:	jbgs_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

The percentage of entity's interest in net assets of the subsidiary redeemed expressed as a percentage

+ References

No definition available.

+ Details

Name:	jbgs_NoncontrollingInterestOwnershipPercentageRedeemed
Namespace Prefix:	jbgs_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of partners with redemption of interest during the period.

+ References

No definition available.

+ Details

Name:	jbgs_NumberOfPartnersRedeemedInterest
Namespace Prefix:	jbgs_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_MinorityInterestLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

+ References

No definition available.

+ Details

Name:	us-gaap_MinorityInterestOwnershipPercentageByParent
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of units or equivalent units outstanding for all classes.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 5
-Subparagraph (SAB TOPIC 4.F)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480008/505-10-S99-5

+ Details

Name:	us-gaap_UnitsOfPartnershipInterestAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_StatementClassOfStockAxis=jbgs_OPUnitsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_OwnershipAxis=jbgs_JBGSmithLPMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_OwnershipAxis=jbgs_ConsolidatedRealEstateVentureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Redeemable Noncontrolling Interests - Narrative (Details)	1 Months Ended		9 Months Ended
	Feb. 28, 2023 item	Oct. 31, 2022 item	Sep. 30, 2023 shares	Sep. 30, 2022 shares
OP Units
Noncontrolling Interest [Line Items]
Redemption of common limited partnership units to common shares			2,100,000	493,596
JBG Smith, LP
Noncontrolling Interest [Line Items]
Ownership interest by parent			87.70%
JBG Smith, LP \| OP Units
Noncontrolling Interest [Line Items]
Units outstanding			13,700,000
Ownership interest by parent			12.30%
Consolidated Real Estate Venture
Noncontrolling Interest [Line Items]
Ownership interest by parent			100.00%	96.00%
Number of partners who redeemed interest during period \| item	1	1
Interest redeemed	0.30%	3.70%