Quarterly report pursuant to Section 13 or 15(d)

Mandatorily-Redeemable Preferred Stock (Detail)

v3.7.0.1
Mandatorily-Redeemable Preferred Stock (Detail) - USD ($)
$ / shares in Units, $ in Thousands
 6 Months Ended 36 Months Ended
Aug. 17, 2016
Jun. 30, 2017
Jun. 30, 2016
Mar. 31, 2017
Dec. 31, 2016
Subsidiary, Sale of Stock [Line Items]          
Common stock, shares issued (in shares)   11,850,624     10,024,875
Proceeds from issuance of preferred stock   $ 28,800      
Proceeds from issuance of equity   $ 20,722 $ 0    
Redemption price (in dollars per share)   $ 25.98      
Offering costs   $ 1,225 $ 252    
Fair value of preferred stock   $ 29,900      
Registration Statement          
Subsidiary, Sale of Stock [Line Items]          
Number of shares issued (in shares)   0      
Proceeds from issuance of equity       $ 73,100  
Registration Statement | Preferred Stock          
Subsidiary, Sale of Stock [Line Items]          
Common stock, shares issued (in shares)   1,150,000      
Series A Preferred Stock          
Subsidiary, Sale of Stock [Line Items]          
Number of shares issued (in shares) 1,000,000        
Dividend rate (as percent) 6.375%        
Par value (in dollars per share) $ 0.001        
Average sales price price (in dollars per share) $ 25        
Proceeds from issuance of equity $ 27,600        
Redemption price (in dollars per share) $ 25        
Offering costs $ 1,200        
Series A Preferred Stock | Preferred Stock          
Subsidiary, Sale of Stock [Line Items]          
Distributions per share   $ 0.796875      
Series A Preferred Stock | January 31, 2017 | Preferred Stock          
Subsidiary, Sale of Stock [Line Items]          
Distributions per share   0.1328125      
Series A Preferred Stock | February 28, 2017 | Preferred Stock          
Subsidiary, Sale of Stock [Line Items]          
Distributions per share   0.1328125      
Series A Preferred Stock | March 31, 2017 | Preferred Stock          
Subsidiary, Sale of Stock [Line Items]          
Distributions per share   0.1328125      
Series A Preferred Stock | April 28, 2017 | Preferred Stock          
Subsidiary, Sale of Stock [Line Items]          
Distributions per share   0.1328125      
Series A Preferred Stock | May 31, 2017 | Preferred Stock          
Subsidiary, Sale of Stock [Line Items]          
Distributions per share   0.1328125      
Series A Preferred Stock | June 30, 2017 | Preferred Stock          
Subsidiary, Sale of Stock [Line Items]          
Distributions per share   $ 0.1328125      
Series A Preferred Stock | Over-allotment option          
Subsidiary, Sale of Stock [Line Items]          
Number of shares issued (in shares) 150,000