Shareholders' Equity (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Equity, Class of Treasury Stock [Line Items]
Common Stock, Par or Stated Value Per Share	$ 1	$ 1
Repurchase plan period, in years	1 year
Shares held at cost	334,311	371,513
Common stock shares authorized	15,000,000	15,000,000
Dividend Reinvestment Plan (DRIP) [Member]
Equity, Class of Treasury Stock [Line Items]
Common stock shares authorized	1,000,000
Addition to capital from dividend reinvestment plan	$ 991
Shares purchased through DRIP, shares	30,375
Shares purchased through DRIP, value	$ 991
Dividend Reinvestment plan shares remain to be issues	614,355
Dividend Reinvestment Plan (DRIP) - Quarterly Dividends [Member]
Equity, Class of Treasury Stock [Line Items]
Addition to capital from dividend reinvestment plan	$ 669
Dividend Reinvestment Plan (DRIP) - Optional Cash Contributions [Member]
Equity, Class of Treasury Stock [Line Items]
Addition to capital from dividend reinvestment plan	$ 322