Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $)	Sep. 30, 2011	Dec. 31, 2010	Sep. 30, 2010
Shareholders' equity:
Common stock, par value	$ 1.00	$ 1.00	$ 1.00
Common stock, shares outstanding	103,760,672	107,020,728	107,934,798
Preferred stock, par value
Preferred stock, shares outstanding	175,737	216,753	216,753