Consolidated Balance Sheets (Parenthetical) (USD $)	Jun. 30, 2012	Dec. 31, 2011
Consolidated Balance Sheets (Parenthetical) [Abstract]
Common stock, par value	$ 0.50	$ 0.50
Common stock, shares authorized	300,000,000	300,000,000
Common stock, shares issued	140,323,118	139,525,580
Treasury stock, shares	759,476	710,482