Consolidated Statement of Changes in Stockholders' Equity and Noncontrolling Interests (Unaudited) - 9 months ended Sep. 30, 2015 - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Noncontrolling Interests	Redeemable Noncontrolling Interests	Series D Cumulative Convertible Preferred Stock Preferred Stock	Series E Cumulative Redeemable Preferred Stock Preferred Stock
Beginning balance at Dec. 31, 2014	$ 3,895,243	$ 715	$ 3,461,189	$ 0	$ (628)	$ 66,804		$ 237,163	$ 130,000
Beginning balance (shares) at Dec. 31, 2014		71,463,876
Increase (Decrease) in Stockholders' Equity
Net Income	102,341			102,212		129
Total other comprehensive income	35,895				35,866	29
Contributions by noncontrolling interests	340					340
Distributions to noncontrolling interests	0					0
Issuances of common stock	5,052	$ 1	5,051
Issuances of common stock (shares)		56,874
Issuances pursuant to stock plan	19,602	$ 2	19,600
Issuances pursuant to stock plan (in shares)		270,140
Purchase of noncontrolling interest	(113,967)		(48,463)			(65,504)
Dividends declared on common stock	(164,806)			(164,806)
Dividends on preferred stock	(18,740)			(18,740)
Distributions in excess of earnings			(81,334)	81,334
Ending balance (shares) at Sep. 30, 2015		71,790,890
Ending balance at Sep. 30, 2015	3,760,960	$ 718	$ 3,356,043	$ 0	$ 35,238	$ 1,798		$ 237,163	$ 130,000
Beginning balance at Dec. 31, 2014	14,315						$ 14,315
Increase (Decrease) in Temporary Equity [Roll Forward]
Net Income							796
Total other comprehensive income							0
Distributions to noncontrolling interests							(893)
Ending balance at Sep. 30, 2015	$ 14,218						$ 14,218