Annual report pursuant to Section 13 and 15(d)

Stockholder's Equity (Details)

v3.20.4
Stockholder's Equity (Details) - USD ($)
 12 Months Ended
Oct. 30, 2018
May 10, 2017
Apr. 18, 2017
Jan. 27, 2015
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Mar. 21, 2020
Nov. 09, 2018
Aug. 06, 2018
Dec. 31, 2017
Class of Stock [Line Items]                      
Preferred stock, authorized (in shares)         10,000,000.0            
Preferred stock, par value (in dollars per share)         $ 0.001            
Repurchases of Series A preferred stock         $ 161,997 $ 60,550 $ 4,275,553        
Preferred stock, outstanding (in shares)         50,108            
Common shares issued (in shares)         13,651,521 13,638,916          
Common shares outstanding (in shares)         13,651,521 13,638,916          
Aggregate offering price of shelf registration                 $ 600,000,000.0    
Current availability         $ 600,000,000.0            
Dividend Reinvestment Plan                      
Class of Stock [Line Items]                      
Reinvestment of distributions to stockholders (in shares) 1,000,000       22,003            
Remaining availability (in shares)         977,997            
Series A Preferred Stock                      
Class of Stock [Line Items]                      
Preferred stock, authorized (in shares)         10,000,000 10,000,000          
Preferred stock, par value (in dollars per share)         $ 0.001 $ 0.001          
Preferred stock interest rate         7.375% 7.375%          
Preferred stock, issued (in shares)       22,500 50,108 50,197          
Preferred stock, liquidation preference (in dollars per share)         $ 2,500 $ 2,500          
Preferred stock, outstanding (in shares)         50,108 50,197          
Common Stock                      
Class of Stock [Line Items]                      
Authorized amount of shares to be repurchased               $ 5,000,000.0      
Common shares outstanding (in shares)         13,651,521 13,638,916 11,960,225 [1]       11,915,830
Reinvestment of distributions to stockholders (in shares)           11,076 41,317        
Depositary Shares                      
Class of Stock [Line Items]                      
Preferred stock, par value (in dollars per share)         $ 50.11            
Percent equivalent of preferred shares         1.00%            
Dividends (in dollars per share)         $ 1.84375            
Preferred stock, liquidation preference (in dollars per share)         $ 25.00            
Repurchase of stock (in shares)             177,773        
Repurchases of Series A preferred stock             $ 4,300,000        
Preferred stock, outstanding (in shares)         5,010,814            
Depositary Shares | Underwritten Public Offering                      
Class of Stock [Line Items]                      
Shares sold in offering (in shares)   150,000 2,800,000 2,250,000              
Sale of stock (in dollars per share)   $ 25.00 $ 25.00                
Shares outstanding (in shares)   5,200,000                  
Depositary Shares | Series A Preferred Stock                      
Class of Stock [Line Items]                      
Authorized amount of shares to be repurchased                   $ 10,000,000.0  
Repurchase of stock (in shares)         8,913 2,500          
Repurchases of Series A preferred stock         $ 162,000 $ 61,000          
Preferred Stock | Underwritten Public Offering                      
Class of Stock [Line Items]                      
Shares outstanding (in shares)   52,000                  
Preferred Stock | Series A Preferred Stock                      
Class of Stock [Line Items]                      
Preferred stock interest rate         7.375%            
[1] (2) The retained earnings balance at December 31, 2018 was generated due to the timing of quarterly dividends and quarterly net income. In the fourth quarter of 2018, net income was greater than dividends due to the gain on sale of leased property, net from the sale of the Portland Terminal Facility resulting in a retained earnings balance as of December 31, 2018.