Quarterly report pursuant to Section 13 or 15(d)

Stockholder's Equity (Details)

v3.10.0.1
Stockholder's Equity (Details) - USD ($)
 3 Months Ended 6 Months Ended 28 Months Ended
Jun. 30, 2017
Jun. 30, 2018
Jun. 30, 2018
Dec. 31, 2017
Feb. 18, 2016
Class of Stock [Line Items]          
Shares of common stock issued (in shares)   11,933,774 11,933,774 11,915,830  
Aggregate offering price of shelf registration         $ 600,000,000
Reinvestment of dividends paid to common stockholders   $ 610,219      
Current availability under shelf registration   $ 523,800,000 $ 523,800,000    
Series A Cumulative Redeemable Preferred Stock [Member]          
Class of Stock [Line Items]          
Preferred stock interest rate   7.375%      
Depositary Shares [Member]          
Class of Stock [Line Items]          
Shares outstanding   5,200,000 5,200,000    
Preferred Stock [Member]          
Class of Stock [Line Items]          
Shares outstanding   52,000 52,000    
Preferred Stock [Member] | Series A Cumulative Redeemable Preferred Stock [Member]          
Class of Stock [Line Items]          
Preferred stock interest rate   7.375%      
Dividend Reinvestment Plan [Member]          
Class of Stock [Line Items]          
Reinvestment of distributions to stockholders (in shares)     79,153    
Reinvestment of dividends paid to common stockholders     $ 2,400,000    
Underwritten Public Offering [Member] | Depositary Shares [Member]          
Class of Stock [Line Items]          
Reduction in shelf registration availability $ 73,800,000