Investments In Joint Ventures (Aggregate Balance Sheet And Statement Of Income Data For Unconsolidated Joint Ventures) (Details) (USD $)	1 Months Ended			3 Months Ended	6 Months Ended	12 Months Ended
	Dec. 31, 2012	Jan. 31, 2012	Dec. 31, 2011	Dec. 31, 2011	Dec. 31, 2012	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Investments In Joint Ventures [Abstract]
Total assets	$ 917,800,000		$ 1,394,900,000	$ 1,394,900,000	$ 917,800,000	$ 917,800,000		$ 1,394,900,000
Total third party debt	712,700,000		1,093,900,000	1,093,900,000	712,700,000	712,700,000		1,093,900,000
Total equity	165,200,000		261,600,000	261,600,000	165,200,000	165,200,000		261,600,000
Total revenues						131,900,000	[1]	126,600,000	[1]	102,900,000	[1]
Gain On Sale Of Operating Properties, Net Of Tax						49,700,000		17,400,000		0
Net income (loss)						50,500,000		(3,200,000)		(19,100,000)
Equity in income (loss) of joint ventures						20,175,000	[2]	5,679,000	[2]	(839,000)	[2]
Percentage of voting interests acquired	50.00%	80.00%			50.00%	50.00%
Number of unconsolidated equity method investments acquired	1	12
Revenues from discontinued operations attributable to unconsolidated joint venture						$ 23,300,000		$ 37,700,000		$ 34,800,000
Number of operating properties sold			2	4	2	11

[1] (2)Excludes approximately $23.3 million, $37.7 million, and $34.8 million of revenues for the years ended December 31, 2012, 2011, and 2010, respectively, related to discontinued operations within one of our unconsolidated joint ventures resulting from the sale of four operating properties in the fourth quarter of 2011 and the sale of five operating properties by this joint venture in the fourth quarter of 2012. Discontinued operations also relates to the sale of two operating properties in another unconsolidated joint venture during the third and fourth quarters of 2012.

[2] (3)Equity in income (loss) excludes our ownership interest of fee income from various property management services and interest income from mezzanine loans with our joint ventures.