Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Per Share data	Jun. 30, 2011	Dec. 31, 2010
Receivables, allowance for doubtful accounts	$ 30,352	$ 30,945
Preferred stock, par value	$ 0.10	$ 0.10
Preferred stock, shares authorized	20,000	20,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.10	$ 0.10
Common stock, shares authorized	480,000	480,000
Common stock, shares issued	177,039	177,060
Common stock, shares outstanding	165,620	166,048
Treasury stock, shares	11,419	11,012