Consolidated Balance Sheets (Parenthetical) (USD $)	Jun. 30, 2011	Dec. 31, 2010
Consolidated Balance Sheets (Parenthetical)
Common stock, par value	$ 0.50	$ 0.50
Common stock, shares authorized	300,000,000	300,000,000
Common stock, shares issued	139,105,938	138,449,039
Treasury stock, shares	703,065	673,472