Preferred Stock (Narrative) (Details) - USD ($)
 1 Months Ended 9 Months Ended 12 Months Ended
Nov. 15, 2017
Mar. 21, 2017
Feb. 14, 2016
May 26, 2015
Mar. 31, 2017
Sep. 30, 2017
Dec. 31, 2016
Jan. 30, 2009
Preferred stock, no par value           $ 0 $ 0  
Number of shares called by Warrant               326,323
Exercise price of shares called by Warrant               $ 13.79
Preferred stock, value           $ 10,000,000 $ 20,000,000  
Preferred dividend payment terms           The terms of the Series A Preferred Stock call for the payment, if declared by the Corporation's Board of Directors, of cash dividends on February 15th, May 15th, August 15th and November 15th of each year. The holders of the Series A Preferred Stock are entitled to receive, if and when declared by the Board of Directors, out of assets legally available for payment, cumulative cash dividends at a rate per annum of 9% per share of Series A Preferred Stock on a liquidation amount of $1,000 per share with respect to each dividend period from and after February 15, 2014.    
Shares redeemed (value)           $ 10,000,000 $ 10,000,000  
Series A Preferred Stock [Member]                
Preferred stock, shares issued           10,000 20,000 30,000
Preferred stock, value               $ 30,000,000
Payment for repurchase of warrant       $ 120,786        
Preferred stock dividend rate           9.00% 9.00%  
Preferred stock liquidation preference per share           $ 1,000 $ 1,000  
Preferred stock redemption date   Mar. 21, 2017 Feb. 14, 2016          
Shares redeemed (in shares)   10,000 10,000          
Shares redeemed (value)   $ 10,000,000 $ 10,000,000   $ 10,000,000      
Series A Preferred Stock [Member] | Subsequent Event [Member]                
Shares redeemed (in shares) 10,000              
Shares redeemed (value) $ 10,000,000