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The Combination Pro Forma Information (Details) - USD ($) $ in Thousands		3 Months Ended			12 Months Ended
	Jul. 18, 2017	Dec. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Transaction and other costs		$ 15,600	$ 12,600	$ 104,100	$ 27,706	$ 127,739	$ 6,476
Business Acquisition, Pro Forma Revenue						637,672
Business Acquisition, Pro Forma Net Income (Loss)						(19,343)
JBG Companies [Member]
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual						71,300
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual						$ 23,100
Gain on bargain purchase (6)	$ 16,770