Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Consolidated Balance Sheets [Abstract]
Allowance for doubtful accounts	$ 28,715	$ 17,484
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	250,000,000	125,000,000
Common stock, shares issued	157,501,635	80,425,443
Common stock, shares outstanding	157,933,224	80,425,443