Period for which construction commitment will be expended.

No definition available.

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Balance Type:	na
Period Type:	duration

- Definition

General Liability Insurance Coverage Limit, Per Occurrence

+ References

No definition available.

+ Details

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Namespace Prefix:	jbgs_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The number of subsidiaries of our company included as part of the defendants named in a legal action.

+ References

No definition available.

+ Details

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Namespace Prefix:	jbgs_
Data Type:	xbrli:integerItemType
Balance Type:	na
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- Definition

Number of assets under construction.

+ References

No definition available.

+ Details

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

- Definition

Property and Rental Value Insurance Coverage Limit

+ References

No definition available.

+ Details

Name:	jbgs_PropertyandRentalValueInsuranceCoverageLimit
Namespace Prefix:	jbgs_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

It represents the information pertaining to the committed tenant-related obligations.

+ References

No definition available.

+ Details

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Namespace Prefix:	jbgs_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Terrorist Acts Insurance Coverage Limit, Per Occurrence

+ References

No definition available.

+ Details

Name:	jbgs_TerroristActsInsuranceCoverageLimitPerOccurrence
Namespace Prefix:	jbgs_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Total costs accrued as of the balance sheet date for environmental loss contingencies.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
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Reference 2: http://www.xbrl.org/2003/role/recommendedDisclosureRef
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Reference 3: http://www.xbrl.org/2003/role/recommendedDisclosureRef
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Reference 4: http://www.xbrl.org/2003/role/exampleRef
-Topic 410
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef
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-Name Accounting Standards Codification
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481931/410-30-50-7

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 460
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482425/460-10-50-4

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Name:	us-gaap_GuaranteeObligationsMaximumExposure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Number of defendants named in a legal action.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (a)
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Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
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-Section 50
-Paragraph 9
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-9

+ Details

Name:	us-gaap_LossContingencyNumberOfDefendants
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Minimum amount of other commitment not otherwise specified in the taxonomy. Excludes commitments explicitly modeled in the taxonomy, including but not limited to, long-term and short-term purchase commitments, recorded and unrecorded purchase obligations, supply commitments, registration payment arrangements, leases, debt, product warranties, guarantees, environmental remediation obligations, and pensions.

+ References

No definition available.

+ Details

Name:	us-gaap_OtherCommitment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Minimum amount of purchase arrangement in which the entity has agreed to expend funds to procure goods or services from a supplier.

+ References

No definition available.

+ Details

Name:	us-gaap_PurchaseObligation
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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

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

- Details

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- Details

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Namespace Prefix:
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Balance Type:
Period Type:

- Details

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Commitments and Contingencies - Narrative (Details)	1 Months Ended	3 Months Ended
Commitments and Contingencies - Narrative (Details)	Nov. 30, 2023 subsidiary item	Mar. 31, 2025 USD ($) Asset	Dec. 31, 2024 USD ($)
Real estate properties
General liability insurance limit		$ 150,000,000
Property and rental value insurance coverage limit		1,000,000,000
Terrorist acts insurance coverage limit		$ 2,000,000,000
Number of assets under construction \| Asset		1
Construction commitment		$ 61,200,000
Construction commitment period		1 year
Environmental liabilities included in Other liabilities, net		$ 17,468,000	$ 17,468,000
Tenant-related obligations		32,300,000
Consolidated Properties
Real estate properties
Tenant-related obligations		32,200,000
Principal payment guarantees		0
Unconsolidated Properties
Real estate properties
Tenant-related obligations		78,000
Additional capital funding committed amount		8,000,000
Principal payment guarantees		$ 0
Violation of the District of Columbia Antitrust Act
Real estate properties
Number of defendants \| item	14
Number of subsidiaries as part of the total defendants \| subsidiary	1