Variable Interest Entities (Details) $ in Millions	Mar. 31, 2020 USD ($) property	Dec. 31, 2019 USD ($) property
Variable Interest Entity [Line Items]
Number of Real Estate Properties \| property	64
JBG Smith, LP
Variable Interest Entity [Line Items]
Ownership interest by parent	90.30%
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Assets	$ 242.7	$ 242.9
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Number of Real Estate Properties \| property	1	2
Assets	$ 146.6	$ 136.8
Liabilities	$ 7.6	$ 11.8

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

No definition available.

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- Definition

The number of real estate properties owned as of the balance sheet date.

+ References

No definition available.

+ Details

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- 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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- Definition

Carrying amount of the assets in the reporting entity's statement of financial position that relate to the reporting entity's variable interest in the Variable Interest Entity (VIE), where the reporting entity is not the VIE's primary beneficiary.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph a
-URI http://asc.fasb.org/extlink&oid=118582676&loc=d3e5728-111685

+ Details

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Balance Type:	debit
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- Definition

Carrying amount of the liabilities in the reporting entity's statement of financial position that relate to the reporting entity's variable interest in the Variable Interest Entity (VIE), where the reporting entity is not the VIE's primary beneficiary.

+ References

+ Details

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- Details

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- Details

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- Details

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