Other Assets (Details) (USD $)	1 Months Ended	9 Months Ended
	Jun. 30, 2011	Sep. 30, 2011	Dec. 31, 2010
Other assets, details:
Straight-line rent assets, net of allowance of $38,369 and $35,190, respectively		$ 253,656,000	$ 206,862,000
Allowance on straight-line rent assets		38,369,000	35,190,000
Leasing costs, net		85,991,000	86,676,000
Deferred debt issuance costs, net		37,777,000	23,541,000
Goodwill		50,346,000	50,346,000
Marketable equity securities		12,297,000
Other		28,121,000	55,461,000
Total other assets		468,188,000	422,886,000
Additions related to accrued interest receivable		5,400,000
Carrying value of interest accrued		5,400,000
Losses on other-than-temporary impairment on securities, net		10,100,000
Purchase of equity marketable securities	$ 22,400,000