Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data	Sep. 30, 2011	Dec. 31, 2010
Condensed Consolidated Balance Sheets [Abstract]
Accounts receivable, allowance for doubtful accounts	$ 27,355	$ 20,357
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	120,000,000	120,000,000
Common stock, shares issued	72,739,924	70,752,670
Treasury stock, shares	246,037	246,037
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	7,000,000	7,000,000
Preferred stock, shares issued	0	0