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 as of beginning of period (in shares) at Dec. 31, 2017			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	187,662					187,599		63
Unrealized gain on derivative instruments	117						117
Unrealized gain (loss) on marketable securities	(226)						(226)
Repurchase of shares (in shares)			(3,027,557)
Repurchase of shares	(89,910)		$ (30)		(89,880)
Share-based compensation (in shares)			267,014
Share-based compensation	5,338		$ 2		5,010			326
Distributions	(1,997)	(1,997)		0				0
Adjustment for noncontrolling interest					329			(329)
Balance as of end of period (in shares) at Mar. 31, 2018			121,457,073						4,915,196
Balance as of end of period at Mar. 31, 2018	3,401,479	(687,745)	$ 1,214	(3,111,868)	4,295,772	2,785,760	(2,106)	1,189	$ 119,263
Balance as of beginning of period (in shares) at Dec. 31, 2018			121,572,155						4,915,196
Balance as of beginning of period at Dec. 31, 2018	3,183,998	(693,736)	$ 1,216	(3,420,548)	4,305,974	2,870,974	(342)	1,197	$ 119,263
Increase (Decrease) in Stockholders' Equity
Net income	210,597					210,518		79
Unrealized gain on derivative instruments	0
Unrealized gain (loss) on marketable securities	342						342
Repurchase of shares (in shares)			(163,913)
Repurchase of shares	(5,342)		$ (2)		(5,340)
Share-based compensation (in shares)			491,383
Share-based compensation	3,927		$ 5		3,585			337
Distributions	(1,961)	(1,997)		36				0
Adjustment for noncontrolling interest					341			(341)
Balance as of end of period (in shares) at Mar. 31, 2019			121,899,625						4,915,196
Balance as of end of period at Mar. 31, 2019	$ 3,391,561	$ (695,733)	$ 1,219	$ (3,420,512)	$ 4,304,560	$ 3,081,492	$ 0	$ 1,272	$ 119,263