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 9 Months Ended 31 Months Ended
Oct. 30, 2018
Sep. 30, 2017
Sep. 30, 2018
Sep. 30, 2018
Aug. 06, 2018
Dec. 31, 2017
Feb. 18, 2016
Class of Stock [Line Items]              
Document Period End Date     Sep. 30, 2018        
Shares of common stock issued (in shares)     11,949,298 11,949,298   11,915,830  
Aggregate offering price of shelf registration             $ 600,000,000
Reinvestment of dividends paid to common stockholders     $ (1,113,727)        
Current availability under shelf registration     $ 523,400,000 $ 523,400,000      
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      
Authorized repurchase amount         $ 10,000,000    
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)       92,605      
Reinvestment of dividends paid to common stockholders       $ (2,900,000)      
Underwritten Public Offering [Member] | Depositary Shares [Member]              
Class of Stock [Line Items]              
Reduction in shelf registration availability   $ (73,800,000)          
Subsequent Event [Member] | Dividend Reinvestment Plan [Member]              
Class of Stock [Line Items]              
Reinvestment of distributions to stockholders (in shares) 1,000,000