Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock, Authorized shares	5,000,000	5,000,000
Preferred stock, unissued shares	5,000,000	5,000,000
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, Authorized shares	200,000,000	200,000,000
Common stock, shares outstanding	61,839,734	64,257,182
Treasury, shares	16,613,193	14,178,801