Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Jun. 30, 2011	Dec. 31, 2010
Common stock, par value	$ 2.50	$ 2.50
Common stock, shares authorized	8,000,000	8,000,000
Common stock, shares issued	4,416,824	4,374,574
Treasury stock, shares	1,315,237	1,305,237