Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Allowance for doubtful accounts	$ 6,548	$ 6,617
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	7,500,000	7,500,000
Preferred stock, shares issued
Preferred stock, shares outstanding
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	250,000,000	250,000,000
Common stock, shares issued	123,019,494	110,907,782
Common stock, shares outstanding	123,019,494	110,907,782