Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2018	Dec. 31, 2017
Stockholders' equity:
Common stock, par value (in dollars per share)	$ 5	$ 5
Common stock, shares authorized (in shares)	10,000,000	10,000,000
Common stock, shares outstanding (in shares)	5,184,289	5,019,703
Restricted Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Unvested restricted shares (in shares)	13,689	2,245