Transaction Related Costs, Impairment Losses and Other - Schedule of Transaction Related Costs, Impairment Losses and Other (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Transaction Related Costs, Impairment Losses and Other [Line Items]
Non-cash impairment loss	$ 101,360	$ 0	$ 101,360	$ 0
Transaction related costs	230	1,017	379	1,070
Transfer tax	0	0	0	13,103
Transaction related costs, impairment losses and other	$ 101,590	$ 1,017	$ 101,739	$ 14,173
Independence Plaza
Transaction Related Costs, Impairment Losses and Other [Line Items]
Equity method ownership percentage	50.10%		50.10%