Quarterly report pursuant to Section 13 or 15(d)

Subsequent Events - Additional Information (Details)

v3.8.0.1
Subsequent Events - Additional Information (Details) - USD ($)
 1 Months Ended
Oct. 27, 2017
Oct. 19, 2017
Oct. 05, 2015
Oct. 31, 2017
Aug. 31, 2013
Subsequent Event [Line Items]          
Maximum borrowing capacity     $ 150,000,000.0   $ 100,000,000.0
Extension fee on initial maturity (as percent)     0.25%    
Term Loan Facility          
Subsequent Event [Line Items]          
Extension fee on initial maturity (as percent)     0.05%    
Line of credit          
Subsequent Event [Line Items]          
Maximum borrowing capacity     $ 85,000,000.0    
Line of credit | Term Loan Facility          
Subsequent Event [Line Items]          
Maximum borrowing capacity     $ 25,000,000.0    
Subsequent event | Common Stock ATM Program          
Subsequent Event [Line Items]          
Consideration received       $ 200,000  
Number of shares issued (in shares)       10,000  
Subsequent event | Series, A, B and D Preferred ATM Programs          
Subsequent Event [Line Items]          
Number of shares issued (in shares)       0  
Subsequent event | Line of credit          
Subsequent Event [Line Items]          
Term of debt 4 years        
Fees incurred $ 900,000        
Subsequent event | Line of credit | Term Loan Facility          
Subsequent Event [Line Items]          
Maximum borrowing capacity $ 75,000,000.0        
Term of debt 5 years        
Subsequent event | Line of credit | Term Loan Facility | LIBOR          
Subsequent Event [Line Items]          
Basis spread (as percent) 2.75%        
Subsequent event | Arlington, Texas          
Subsequent Event [Line Items]          
Renewal term   10 years      
Subsequent event | Arlington, Texas | Disposed of by sale | Plan          
Subsequent Event [Line Items]          
Consideration received   $ 5,600,000