Consolidated Statements of Equity (Unaudited) (USD $) In Thousands, unless otherwise specified	Total	Redeemable Noncontrolling Partnership Interests [Member]	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Other Comprehensive Income [Member]	Dividends in Excess of Cumulative Earnings [Member]	Noncontrolling Interest [Member]	Parent [Member]
Balance, redeemable noncontrolling partnership interests at Dec. 31, 2010		$ 34,379
Balance at Dec. 31, 2010	1,523,943		23	1,479	1,657,507	7,855	(366,526)	223,605	1,300,338
Net income	56,630						50,969	5,661	50,969
Other Comprehensive Income	(8,774)	(73)				(6,894)		(1,880)	(6,894)
Costs of preferred stock offering	0
Conversion of operating partnership special common units to shares of common stock				(1)	(728)			729	(729)
Dividends declared - common stock	(93,459)						(93,459)		(93,459)
Dividends declared - preferred stock	(31,782)						(31,782)		(31,782)
Issuance of common stock and restricted common stock	235			2	233				235
Cancellation of restricted common stock	(184)				(184)				(184)
Exercise of stock options	1,955			2	1,953				1,955
Accrual under deferred compensation arrangements	41				41				41
Amortization of deferred compensation	1,629				1,629				1,629
Contributions from noncontrolling interests	1,040							1,040
Distributions to noncontrolling interests	31,545	6,405						31,545
Adjustment for noncontrolling interests	(2,181)				(3,243)			1,062	(3,243)
Adjustment to record redeemable noncontrolling interests at redemption value	8,630	(8,630)			8,630				8,630
Redeemable Noncontrolling Partnership Interests [Roll forward]
Net income		3,055
Adjustment for noncontrolling interests		2,181
Balance, redeemable noncontrolling partnership interests at Sep. 30, 2011		24,507
Balance at Sep. 30, 2011	1,426,178		23	1,484	1,667,294	961	(440,798)	197,214	1,228,964
Balance, redeemable noncontrolling partnership interests at Dec. 31, 2011		32,271
Balance at Dec. 31, 2011	1,470,391		23	1,484	1,657,927	3,425	(399,581)	207,113	1,263,278
Net income	(70,507)						(63,514)	6,993	(63,514)
Other Comprehensive Income	1,216	10				962		254	962
Costs of preferred stock offering	(134)				(134)				(134)
Conversion of operating partnership special common units to shares of common stock				(103)	(48,174)			48,277	48,277
Partners' Capital Account, Redemptions	(9,836)							(9,836)
Dividends declared - common stock	(102,581)						(102,581)		(102,581)
Dividends declared - preferred stock	(31,782)						(31,782)		(31,782)
Issuance of common stock and restricted common stock	369			2	367				369
Cancellation of restricted common stock	261				(261)				261
Exercise of stock options	4,434			2	4,432				4,434
Accrual under deferred compensation arrangements	44				44				44
Amortization of deferred compensation	1,957				1,957				1,957
Contributions from noncontrolling interests	5,559							5,559
Distributions to noncontrolling interests	(25,716)	6,221						25,716
Adjustment for noncontrolling interests	2,379				(5,929)			3,550	5,929
Adjustment to record redeemable noncontrolling interests at redemption value	(10,049)	10,049			(4,256)			(5,793)	(4,256)
Acquire controlling interest in shopping center property	(14,498)							14,498
Redeemable Noncontrolling Partnership Interests [Roll forward]
Net income		2,441
Adjustment for noncontrolling interests		2,379
Balance, redeemable noncontrolling partnership interests at Sep. 30, 2012		40,929
Balance at Sep. 30, 2012	$ 1,386,237		$ 23	$ 1,591	$ 1,702,321	$ 4,387	$ (470,430)	$ 148,345	$ 1,237,892