CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Sep. 30, 2019	Dec. 31, 2018
Statement Of Financial Position [Abstract]
Preferred stock, par value (in USD per share)	$ 5.00	$ 5.00
Preferred stock, shares authorized (in shares)	15,000,000	15,000,000
Preferred stock, shares issued (in shares)	0	0
Common stock, par value (in USD per share)	$ 1.00	$ 1.00
Common stock, shares authorized (in shares)	50,000,000	50,000,000
Common stock, shares issued (in shares)	12,889,597	12,835,486
Common stock, shares outstanding (in shares)	11,534,393	11,829,868
Treasury stock (in shares)	1,355,204	1,005,618