Balance Sheet Parenthetical (USD $) In Thousands, except Share data, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Tenant receivables allowance for doubtful accounts	$ 2,154	$ 1,977
Other receivables allowance for doubtful accounts	$ 1,283	$ 1,270
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	15,000,000	15,000,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	350,000,000	350,000,000
Common stock, shares, issued	169,906,529	161,309,652
Common stock, shares outstanding	169,906,529	161,309,652
Preferred stock, shares outstanding Series D
Preferred stock, shares outstanding	1,815,000	1,815,000
Series E Preferred Stock [Member]
Preferred stock, shares outstanding	690,000	690,000