Segment Information - Schedule of Reconciliation of Net Income Attributable to Parent (Details) - USD ($) $ in Thousands		3 Months Ended			12 Months Ended
	Jul. 18, 2017	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Net income (loss) attributable to common shareholders					$ (71,753)	$ 61,974	$ 49,628
Depreciation and amortization					161,659	133,343	144,984
Corporate and other					47,131	48,753	44,424
Third-party real estate services					51,919	19,066	18,217
Share-based compensation related to Formation Transaction					29,251	0	0
Transaction and other costs					127,739	6,476	0
Interest expense					58,141	51,781	50,823
Loss on extinguishment of debt					701	0	0
Income tax expense (benefit)					(9,912)	1,083	420
Third-party real estate services, including reimbursements					63,236	33,882	29,467
Other income					5,167	5,381	10,854
Loss from unconsolidated real estate ventures, net					(4,143)	(947)	(4,283)
Interest and other income, net					1,788	2,992	2,557
Gain on bargain purchase					24,376	0	0
Net loss attributable to redeemable noncontrolling interests					7,328	0	0
Net loss attributable to noncontrolling interest					3	0	0
Consolidated NOI					297,121	281,168	$ 269,901
JBG Companies
Business Acquisition [Line Items]
Share-based compensation related to Formation Transaction		$ 14,800	$ 14,400
Transaction and other costs		$ 12,600	104,100	$ 4,900	$ 127,700	$ 6,500
Gain on bargain purchase	$ 24,376		$ 27,800