Company Earnings Per Share (Schedule Of Computation Of Earnings (Loss) Per Common Share) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Company Earnings Per Share [Line Items]
Income (loss) from continuing operations									$ 25,595	$ (6,991)	$ (95,727)
Noncontrolling interests - consolidated real estate entities									(67)	(20)	8,218
Noncontrolling interests - Operating Partnership									(62)	51	452
Dividends to preferred shareholders	(922)	(922)	(922)	(1,689)	(1,871)	(1,864)	(1,878)	(1,890)	(4,455)	(7,503)	(7,637)
Preferred stock redemption costs				1,757		(1)	37	8	(1,757)	(44)
Unvested restricted stock (allocation of earnings)									(59)	65	29
Income (loss) from continuing operations available to common shareholders									$ 19,195	$ (14,442)	$ (94,665)
Weighted average shares outstanding - basic									50,420,000	48,483,000	45,179,000
Dilutive shares from stock options									388,000
Weighted average common shares outstanding - diluted									50,808,000	48,483,000	45,179,000
Per-share amount: Basic									$ 0.38	$ (0.30)	$ (2.10)
Per-share amount: Diluted									$ 0.38	$ (0.30)	$ (2.10)
Gross Antidilutive [Member]
Company Earnings Per Share [Line Items]
Antidilutive stock options to purchase common stock									531	1,916	2,516