Other Assets (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid assets	$ 50,700,000	$ 45,000,000
Straight-line rent receivables	34,700,000	30,300,000
Above-market intangible assets, net	12,700,000	13,300,000
Deferred financing costs, net	10,600,000	13,800,000
Accounts receivable	6,100,000	8,200,000
Goodwill	3,500,000	3,500,000
Equity investment in joint venture - cost method	1,300,000	1,300,000
Customer relationship intangible assets, net	2,000,000	2,100,000
Notes receivable	100,000	300,000
Allowance for uncollectible accounts	(700,000)	(600,000)
Other	1,700,000	1,200,000
Other Assets	122,709,000	118,382,000
Other Assets (Textual) [Abstract]
Cost method investments income loss from joint venture	$ 400,000	$ 700,000	$ 100,000