Stockholders' Equity - Preferred Stock (Details) (USD $)
 12 Months Ended
Dec. 31, 2014
vote_per_stock
Feb. 19, 2014
Jun. 30, 2013
Feb. 12, 2013
Feb. 09, 2015
Dec. 31, 2013
Dec. 31, 2012
Class of Stock [Line Items]              
Common stock dividends (shares)   30,833   75,530      
Redemption of preferred stock     $ 1,500,000        
Subsequent Event              
Class of Stock [Line Items]              
Common stock dividends (shares)         25,509    
Series B [Member]              
Class of Stock [Line Items]              
Voting rights per stock (vote per stock) 0.8            
Shares convertible for each stock (shares) 0.27            
Preferred stock, per share liquidation value (usd per share) $ 29         $ 29  
Dividends declared per share (usd per share) $ 2.90            
Preferred stock, shares outstanding (shares) 44,258         44,258  
Common stock dividends, declared and undeclared   218,000   167,000      
Common stock dividends, undeclared 159,000         218,000 167,000
Series B [Member] | Subsequent Event              
Class of Stock [Line Items]              
Common stock dividends, declared and undeclared         159,000    
Common Stock              
Class of Stock [Line Items]              
Price per share on issuable shares (usd per share) $ 3.77            
Number of trading dates used to calculated price per share 20 days            
Series E [Member]              
Class of Stock [Line Items]              
Voting rights per stock (vote per stock) 0.25            
Preferred stock, shares outstanding (shares) 27,000         1,731,000  
Common stock dividends, undeclared           1,300,000  
Preferred stock, per share redemption value (usd per share) $ 10         $ 10  
Preferred stock, dividend rate 8.00%            
Cumulative dividends undeclared $ 300,000