Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data	Jun. 30, 2011	Dec. 31, 2010
Consolidated Balance Sheets
Accounts and notes receivable, allowance for doubtful accounts	$ 4,201	$ 3,892
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	225,000,000	225,000,000
Common stock, shares issued	149,447,642	149,063,197
Cost of common stock held in treasury, shares	4,122,396	4,081,134
Common stock held in employee benefit and compensation trusts, shares	73,125	76,259