Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Accounts and rents receivable, allowance	$ 10,582	$ 9,488
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	40,000,000	40,000,000
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	1,460,000,000	1,460,000,000
Common stock, shares issued	884,313,402	869,187,360
Common stock, shares outstanding	884,313,402	869,187,360