Variable Interest Entities (Details) $ in Thousands	1 Months Ended	9 Months Ended
	Jun. 30, 2024 USD ($)	Sep. 30, 2024 USD ($) item	Sep. 30, 2023 USD ($)	Dec. 31, 2023 USD ($) item	Mar. 31, 2021 item
Variable Interest Entities
Payments for redemption of interest	$ 26,600	$ 26,569	$ 647
Purchase of interests	$ 4,700	26,586
Assets		5,182,477		$ 5,518,515
Liabilities		$ 2,841,880		2,825,929
1900 Crystal Drive.
Variable Interest Entities
Number of Towers in Real Estate Property | item					2
JBG Smith, LP
Variable Interest Entities
Ownership interest by parent		85.80%
Unconsolidated VIEs
Variable Interest Entities
Equity Method Investments		$ 88,600		$ 87,300
Consolidated VIEs
Variable Interest Entities
Number of consolidated variable interest entities | item		1		2
Assets		$ 271,400		$ 503,200
Liabilities		$ 173,100		$ 293,300