Consolidated Statement of Equity (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Stock	Additional Paid-In-Capital	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Noncontrolling Interests	Series C Preferred Stock	Series D Preferred Stock
Balance at Dec. 31, 2011	$ 6,453,309	$ 892	$ 4,236,959	$ (308,708)	$ (28,445)	$ 1,704,506	$ 477,762	$ 274,022	$ 96,321
Balance (in shares) at Dec. 31, 2011		85,783,000
Increase (Decrease) in Stockholders' Equity
Net income after allocation to noncontrolling interests in SLGOP	148,343					143,385	4,958
Comprehensive Income:	32				32
Preferred dividends	(15,089)					(15,089)
Redemption of units and DRIP proceeds	100,024	13	100,011
Redemption of units and DRIP proceeds (in shares)		1,311,000
Reallocation of noncontrolling interest in the Operating Partnership	(46,810)					(46,810)
Deferred compensation plan & stock award, net	(10,614)	3	541	(11,158)
Deferred compensation plan & stock award, net (in shares)		67,000
Amortization of deferred compensation plan	13,208		13,208
Proceeds from issuance of common stock	201,307	27	201,280
Proceeds from issuance of common stock (in shares)		2,640,000
Proceeds from stock options exercised	5,654	1	5,653
Proceeds from stock options exercised (in shares)		137,000
Consolidation of joint venture interest	18,799						18,799
Cash distributions to noncontrolling interests	(11,999)						(11,999)
Cash distribution declared ($0.50 per common share, none of which represented a return of capital for federal income tax purposes)	(44,832)					(44,832)
Balance at Jun. 30, 2012	$ 6,811,332	$ 936	$ 4,557,652	$ (319,866)	$ (28,413)	$ 1,741,160	$ 489,520	$ 274,022	$ 96,321
Balance (in shares) at Jun. 30, 2012	89,937,501	89,938,000