Investments In Unconsolidated Real Estate Entities (Summary Of Financial Information For Apartment LLCs) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012		Dec. 31, 2011		Mar. 31, 2011	Dec. 31, 2010
Real Estate Properties [Line Items]
Real estate assets, net of accumulated depreciation of $33,887 and $32,780 at March 31, 2012 and December 31, 2011, respectively	$ 2,083,008		$ 2,075,517
Total assets	2,145,381		2,139,064
Total liabilities	1,058,614		1,084,701
Members' equity	1,079,681		1,047,523		936,559	967,295
Total liabilities and members' equity	2,145,381		2,139,064
Net accumulated depreciation	785,996		767,017
Investments in unconsolidated real estate entities	16,053		15,945
Apartment LLCs [Member]
Real Estate Properties [Line Items]
Real estate assets, net of accumulated depreciation of $33,887 and $32,780 at March 31, 2012 and December 31, 2011, respectively	216,526		217,443
Assets held for sale, net			28,846
Cash and other	6,479		6,526
Total assets	223,005		252,815
Mortgage notes payable	177,723		206,495
Other liabilities	2,919		2,737
Total liabilities	180,642		209,232
Members' equity	42,363		43,583
Total liabilities and members' equity	223,005		252,815
Company's equity investment in Apartment LLCs	(10,386)	[1]	(8,601)	[1]
Net accumulated depreciation	$ 33,887		$ 32,780

[1] At March 31, 2012 and December 31, 2011, the Company's equity investment includes its credit investments of $16,053 and $15,945, respectively, discussed above.