Quarterly report pursuant to Section 13 or 15(d)

Series A Term Preferred Stock (Detail)

v3.10.0.1
Series A Term Preferred Stock (Detail) - USD ($)
$ / shares in Units, $ in Thousands
1 Months Ended 6 Months Ended
Mar. 27, 2018
Aug. 31, 2016
Jun. 30, 2018
Jun. 30, 2017
Dec. 31, 2017
Subsidiary, Sale of Stock [Line Items]          
Preferred stock par value (in dollars per share)     $ 0.001   $ 0
Common stock, shares issued (in shares)     16,023,872   13,791,574
Proceeds from issuance of common and preferred equity     $ 25,113 $ 20,722  
Offering costs $ 12,700   $ 935 $ 1,225  
Series A Preferred Stock          
Subsidiary, Sale of Stock [Line Items]          
Dividend rate (as percent)   6.375%      
Preferred stock par value (in dollars per share)   $ 0.001      
Average sales price price (in dollars per share)   $ 25      
Proceeds from issuance of common and preferred equity   $ 27,600      
Redemption price (in dollars per share)   $ 25 $ 25.5    
Offering costs   $ 1,200      
Fair value of preferred stock     $ 29,300    
Series A Preferred Stock | Preferred Stock          
Subsidiary, Sale of Stock [Line Items]          
Common stock, shares issued (in shares)   1,150,000      
Proceeds from issuance of preferred stock   $ 28,800