CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares shares in Thousands	Dec. 31, 2019	Dec. 31, 2018
Stockholders' equity
Preferred Stock, par value (in dollars per share)	$ 1	$ 1
Preferred Stock, shares authorized (in shares)	1,000	1,000
Preferred Stock, shares issued (in shares)	0	0
Common Stock [Member]
Stockholders' equity
Common Stock, par value (in dollars per share)	$ 1	$ 1
Common Stock, shares authorized (in shares)	50,000	50,000
Common Stock, shares issued (in shares)	29,431	29,079
Treasury Stock, common stock shares (in shares)	11,850	10,300
Convertible Class A Common Stock [Member]
Stockholders' equity
Common Stock, shares authorized (in shares)	15,000	15,000
Common Stock, shares issued (in shares)	2,054	2,280
Treasury Stock, common stock shares (in shares)	522	522