Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 160	$ 160
Percentage of noncumulative preferred stock	10.00%	10.00%
Preferred stock, par value	$ 50	$ 50
Preferred stock, shares authorized	640	640
Preferred stock, shares issued	640	640
Preferred stock, shares outstanding	640	640
Common stock, par value	$ 0.50	$ 0.50
Common stock, shares authorized	15,000,000	15,000,000
Common stock, shares issued	4,859,871	4,850,014
Common stock, shares outstanding	4,859,871	4,850,014