Investments In Joint Ventures (Aggregate Balance Sheet And Statement Of Income Data For Unconsolidated Joint Ventures) (Details) (USD $)	1 Months Ended		3 Months Ended
	Jan. 31, 2012	Dec. 31, 2011	Mar. 31, 2012		Dec. 31, 2011	Mar. 31, 2011
Investments In Joint Ventures [Abstract]
Total assets		$ 1,394,900,000	$ 1,084,100,000	[1]	$ 1,394,900,000
Total third-party debt		1,093,900,000	852,900,000	[1]	1,093,900,000
Total equity		261,600,000	204,600,000	[1]	261,600,000
Total revenues			40,500,000	[2]		33,000,000	[2]
Net loss			(1,700,000)			(2,600,000)
Equity in income			366,000	[3]		374,000	[3]
Percentage of voting interests acquired	80.00%
Number of unconsolidated equity method investments acquired	12		12
Revenues from discontinued operations attributable to unconsolidated joint venture						$ 2,900,000
Number of operating properties sold		2	3		4

[1] In January 2012, as a result of our purchase of the remaining 80% ownership interest in previously unconsolidated joint ventures, we consolidated twelve joint ventures previously accounted for in accordance with the equity method. Refer to Note 6, "Property Acquisitions, Discontinued Operations, and Assets Held for Sale," for further discussion of the acquisition.

[2] Approximately $2.9 million of revenues for the three months ended March 31, 2011 relates to discontinued operations within one of our unconsolidated joint ventures resulting from the sale of four operating properties in the fourth quarter of 2011.

[3] Equity in income excludes our ownership interest of fee income from various property management services provided by us to our joint ventures.