Common Stock and Earnings per Share (Schedule of Common Stock Outstanding) (Details)	12 Months Ended
	Dec. 31, 2017 shares
Earnings Per Share [Abstract]
Shares outstanding at January 1	11,188,466
10% stock dividend issued December 15, 2017	1,116,711
Issuance of common stock:
Employee restricted stock grants	3,825
Employee SARs exercised	7,547
Directors' compensation	8,389
Shares repurchased	(38,042)
Shares outstanding at December 31	12,286,896