Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Receivables, allowance for doubtful accounts	$ 31,533	$ 31,328
Preferred stock, par value	$ 0.10	$ 0.10
Preferred stock, shares authorized	20,000	20,000
Preferred stock, shares issued
Preferred stock, shares outstanding
Common stock, par value	$ 0.10	$ 0.10
Common stock, Shares authorized	480,000	480,000
Common stock, shares issued	177,271	177,312
Common stock, shares outstanding	162,170	163,441
Treasury stock, shares	15,101	13,871