CONSOLIDATED BALANCE SHEETS [Parenthetical] - $ / shares	Sep. 30, 2018	Dec. 31, 2017
Preferred stock, par value (in dollars per share)	$ 10	$ 10
Preferred stock, shares authorized	2,000,000	2,000,000
Preferred stock, shares issued	0	0
Treasury stock, shares	702,000	631,000
Common Class A [Member]
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares authorized	7,000,000	7,000,000
Common stock, shares issued	4,394,000	4,203,000
Common Class B [Member]
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares authorized	2,000,000	2,000,000
Common stock, shares issued	0	0