Summary of Significant Accounting Policies - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Jan. 01, 2018	Dec. 31, 2017
Variable Interest Entity [Line Items]
Costs related to shareholder activism	$ 0	$ 19,369	$ 0	$ 19,369	$ 0
Distributions in excess of co-venture obligation	0			0			$ 31,150
Financing arrangement obligation	384,431			384,431			0
Accumulated deficit	(1,520,209)			(1,520,209)			$ (830,279)
Capitalized internal leasing costs	$ 5,141		$ 5,376	16,928	17,075
Increase in net cash provided by investing activities				$ 256,159	164,691
ASU 2016-18
Variable Interest Entity [Line Items]
Increase in net cash provided by investing activities					$ 785
Joint Venture | Chandler Freehold | Difference between revenue guidance in effect before and after topic 606 | ASU 2014-09 | Financing Arrangement
Variable Interest Entity [Line Items]
Financing arrangement obligation						$ 393,709
Accumulated deficit						424,859
Joint Venture | Chandler Freehold
Variable Interest Entity [Line Items]
Distributions in excess of co-venture obligation						$ 31,150