Stock Option Plans (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Stock or Unit Option Plan Expense	$ 74,048	$ 79,140	$ 74,612
Officer and Employee Plans [Member]
Percentage Of Incentive Stock Options Vest On Second Anniversary Of Grant Date	30.00%
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	380,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value	73,000	56,000	125,000
Percentage Of Incentive Stock Options Vest On Third Anniversary Of Grant Date	30.00%
Percentage Of Incentive Stock Options Vest On Fourth Anniversary Of Grant Date	40.00%
Weighted-Average Contractual Remaining Term Outstanding (in years)	10 years
Incentive Stock Option Description	The option price for incentive stock options shall be not less than 100 percent of the fair market value of the common stock on the date of the grant.
Officer and Employee Plans [Member] | Long Term Incentive Plan 2002 [Member]
Shares Held in Employee Stock Option Plan, Allocated	1,200,000
Officer and Employee Plans [Member] | Cornerstone Statutory Option Plan 1996 [Member]
Shares Held in Employee Stock Option Plan, Allocated	220,000
Board Of Directors Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	600,000
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	70,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value		$ 11,900	$ 34,000
Board Of Directors Plan [Member] | Long Term Incentive Plan 2002 [Member]
Shares Held in Employee Stock Option Plan, Allocated	1,200,000
Percentage Of Board Of Directors Plan Vest On First Anniversary Of Grant Date	50.00%
Percentage Of Board Of Directors Plan Vest On Second Anniversary Of Grant Date	50.00%
Weighted-Average Contractual Remaining Term Outstanding (in years)	10 years