Redeemable Noncontrolling Interests - Summary of the Activity of Redeemable Noncontrolling Interests (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Temporary Equity
Balance as of the beginning of the period	$ 503,040	$ 584,763	$ 612,758	$ 558,140
OP Unit redemptions	(4,752)	(316)	(35,878)	(57,318)
LTIP Units issued in lieu of cash bonuses (1)	450	818	4,066	3,954
Net income (loss) attributable to redeemable noncontrolling interests	(3,483)	(288)	1,767	3,099
Other comprehensive loss	(182)	(1,503)	(3,755)	(2,886)
Contributions (distributions)	(3,782)	(3,838)	(3,782)	(3,838)
Share-based compensation expense	20,465	15,343	37,246	31,616
Adjustment to redemption value	(12,673)	(20,751)	(113,339)	41,461
Balance as of the end of the period	499,083	574,228	499,083	574,228
JBG Smith, LP
Temporary Equity
Balance as of the beginning of the period	496,984	578,781	606,699	552,159
OP Unit redemptions	(4,752)	(316)	(35,878)	(57,318)
LTIP Units issued in lieu of cash bonuses (1)	450	818	4,066	3,954
Net income (loss) attributable to redeemable noncontrolling interests	(3,443)	(292)	1,810	3,094
Other comprehensive loss	(182)	(1,503)	(3,755)	(2,886)
Contributions (distributions)	(3,782)	(3,838)	(3,782)	(3,838)
Share-based compensation expense	20,465	15,343	37,246	31,616
Adjustment to redemption value	(12,673)	(20,751)	(113,339)	41,461
Balance as of the end of the period	493,067	568,242	493,067	568,242
Consolidated Real Estate Venture
Temporary Equity
Balance as of the beginning of the period	6,056	5,982	6,059	5,981
Net income (loss) attributable to redeemable noncontrolling interests	(40)	4	(43)	5
Balance as of the end of the period	$ 6,016	$ 5,986	$ 6,016	$ 5,986