Condensed Consolidated Balance Sheet (Parenthetical) (USD $) In Thousands, except Share data	Jun. 30, 2011	Dec. 31, 2010
Allowance for doubtful accounts	$ 12,991	$ 14,636
Property and Equipment, accumulated depreciation	$ 292,556	$ 281,651
Preferred Stock, shares issued	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares issued	211,992,082	212,047,774
Common stock, shares outstanding	211,992,082	212,047,774