Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Loss [Abstract]
Net income (loss)	$ (25,005)	$ 10,532	$ (17,093)	$ 35,452
OTHER COMPREHENSIVE INCOME (LOSS):
Change in fair value of derivative financial instruments	(278)	(7,014)	(39,489)	(33,966)
Reclassification of net (income) loss on derivative financial instruments from accumulated other comprehensive loss into interest expense	3,823	(211)	8,137	(2,001)
Other comprehensive income (loss)	3,545	(7,225)	(31,352)	(35,967)
COMPREHENSIVE INCOME (LOSS)	(21,460)	3,307	(48,445)	(515)
Net (income) loss attributable to redeemable noncontrolling interests	2,212	(1,172)	445	(4,271)
Other comprehensive (income) loss attributable to redeemable noncontrolling interests	(309)	803	3,446	3,689
COMPREHENSIVE INCOME (LOSS) ATTRIBUTABLE TO JBG SMITH PROPERTIES	$ (19,557)	$ 2,938	$ (44,554)	$ (1,097)