Accounts Receivable, Net (Schedule Of Accounts Receivable) (Details) (USD $)	9 Months Ended
	Sep. 30, 2012		Dec. 31, 2011
Straight-line rent receivable	$ 30,071,000		$ 26,499,000
Deferred rent receivable	0	[1]	4,420,000	[1]
Allowance for doubtful accounts	(3,038,000)		(5,152,000)
Total	35,704,000		35,005,000
Tenants [Member]
Carrying amounts of accounts receivable	6,901,000		6,874,000
Non-Tenants [Member]
Carrying amounts of accounts receivable	1,168,000		1,265,000
Canada Revenue Agency [Member]
Carrying amounts of accounts receivable	602,000		1,099,000
Private Equity Firm Guarantor [Member]
Deferred rent receivable			3,400,000
Other Guarantor [Member]
Deferred rent receivable			1,000,000
unguaranteed rent payments received	400,000
write off of accounts receivable	$ 600,000

[1] At December 31, 2011, rent deferral payments of $3.4 million were guaranteed by a private equity firm and $1.0 million were unguaranteed but fully reserved. In June 2012, in conjunction with the tenant's sale of its operations, the guaranteed rent deferral payments of $3.4 million were paid in full, and unguaranteed rent deferral payments of $0.4 million were received and the remaining unguaranteed rent deferral payments of $0.6 million were written off to the previously established allowance for doubtful accounts.