Other Assets (Details) (USD $)	Jun. 30, 2011	Dec. 31, 2010
Items included in other assets
Prepaid assets	$ 31,300,000	$ 27,900,000
Straight-line rent receivables	29,500,000	27,000,000
Above-market intangible assets, net	13,200,000	13,400,000
Deferred financing costs, net	10,000,000	12,000,000
Accounts receivable	6,300,000	6,100,000
Goodwill	3,500,000	3,500,000
Equity investment in joint venture - cost method	1,266,000	1,300,000
Customer relationship intangible assets, net	1,100,000	1,200,000
Notes receivable	300,000	3,800,000
Allowance for uncollectible accounts	(1,300,000)	(1,200,000)
Other	5,400,000	1,500,000
Other Assets	$ 100,641,000	$ 96,510,000
Other Assets (Textuals) [Abstract]
Number of unconsolidated joint ventures	1