Condensed Consolidated Statements of Equity - USD ($) $ in Thousands	Total	Preferred Stock	Common Stock	Additional Paid-In Capital	Treasury Stock	Distributions in Excess of Net Income	Stockholders’ Investment	Nonredeemable Noncontrolling Interests
Beginning balance at Dec. 31, 2017	$ 2,825,111	$ 6,867	$ 430,350	$ 3,604,776	$ (148,373)	$ (1,121,647)	$ 2,771,973	$ 53,138
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	16,406					16,043	16,043	363
Common stock issued pursuant to stock based compensation	(759)		232	(991)			(759)
Amortization of stock options and restricted stock, net of forfeitures	542		(9)	551			542
Distributions to nonredeemable noncontrolling interests	(399)							(399)
Common dividends	(27,315)					(27,315)	(27,315)
Ending balance at Mar. 31, 2018	2,835,915	6,867	430,573	3,604,336	(148,373)	(1,110,590)	2,782,813	53,102
Beginning balance at Dec. 31, 2018	2,821,156	6,867	430,725	3,606,191	(148,473)	(1,129,445)	2,765,865	55,291
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	36,005					35,341	35,341	664
Common stock issued pursuant to stock based compensation	(904)		202	(1,106)			(904)
Amortization of stock options and restricted stock, net of forfeitures	607			607			607
Contributions from nonredeemable noncontrolling interests	2,581							2,581
Distributions to nonredeemable noncontrolling interests	(724)							(724)
Common dividends	(30,492)					(30,492)	(30,492)
Ending balance at Mar. 31, 2019	$ 2,828,229	$ 6,867	$ 430,927	$ 3,605,692	$ (148,473)	$ (1,124,596)	$ 2,770,417	$ 57,812