CONDENSED CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Thousands	Total	Cumulative Preferred Distributions	Common Shares	Cumulative Common Distributions	Additional Paid in Capital	Cumulative Net Income	Cumulative Other Comprehensive Loss	Noncontrolling Interest	Series D
Balance (in shares) at Dec. 31, 2017	124,217,616		124,217,616						4,915,196
Balance as of beginning of period at Dec. 31, 2017	$ 3,300,495	$ (685,748)	$ 1,242	$ (3,111,868)	$ 4,380,313	$ 2,596,259	$ (95)	$ 1,129	$ 119,263
Increase (Decrease) in Stockholders' Equity
Net income (loss)	224,709					224,632		77
Unrealized gain on derivative instruments	456						456
Unrealized gain on marketable securities	72						72
Repurchase of shares (in shares)			(3,027,557)
Repurchase of shares	(89,910)		$ (30)		(89,880)
Share-based compensation (in shares)			292,614
Share-based compensation	10,480		$ 3		9,822			655
Contributions	1							1
Distributions	$ (3,994)	(3,994)
Adjustment for noncontrolling interest					567			(567)
Balance (in shares) at Jun. 30, 2018	121,482,673		121,482,673						4,915,196
Balance as of end of period at Jun. 30, 2018	$ 3,442,309	(689,742)	$ 1,215	(3,111,868)	4,300,822	2,822,793	(1,469)	1,295	$ 119,263
Increase (Decrease) in Stockholders' Equity
Net income (loss)	37,047
Unrealized gain on derivative instruments	339
Unrealized gain on marketable securities	$ 298
Balance (in shares) at Jun. 30, 2018	121,482,673		121,482,673						4,915,196
Balance as of end of period at Jun. 30, 2018	$ 3,442,309	$ (689,742)	$ 1,215	$ (3,111,868)	$ 4,300,822	$ 2,822,793	$ (1,469)	$ 1,295	$ 119,263