Quarterly report pursuant to Section 13 or 15(d)

Subsequent Events - Monthly Distributions Declared by Company's Board of Directors (Detail)

v3.7.0.1
Subsequent Events - Monthly Distributions Declared by Company's Board of Directors (Detail) - $ / shares
 6 Months Ended
Jun. 30, 2017
Jul. 11, 2017
July 31, 2017    
Subsequent Event [Line Items]    
Record Date Jul. 21, 2017  
Payment Date Jul. 31, 2017  
August 31, 2017    
Subsequent Event [Line Items]    
Record Date Aug. 21, 2017  
Payment Date Aug. 31, 2017  
September 29, 2017    
Subsequent Event [Line Items]    
Record Date Sep. 20, 2017  
Payment Date Sep. 29, 2017  
Common Stock | Subsequent event    
Subsequent Event [Line Items]    
Distributions per share   $ 0.132
Common Stock | July 31, 2017 | Subsequent event    
Subsequent Event [Line Items]    
Distributions per share   0.044
Common Stock | August 31, 2017 | Subsequent event    
Subsequent Event [Line Items]    
Distributions per share   0.044
Common Stock | September 29, 2017 | Subsequent event    
Subsequent Event [Line Items]    
Distributions per share   0.044
Preferred Stock | Series A Preferred Stock    
Subsequent Event [Line Items]    
Distributions per share $ 0.796875  
Preferred Stock | Series A Preferred Stock | Subsequent event    
Subsequent Event [Line Items]    
Distributions per share   0.3984375
Preferred Stock | Series A Preferred Stock | July 31, 2017 | Subsequent event    
Subsequent Event [Line Items]    
Distributions per share   0.1328125
Preferred Stock | Series A Preferred Stock | August 31, 2017 | Subsequent event    
Subsequent Event [Line Items]    
Distributions per share   0.1328125
Preferred Stock | Series A Preferred Stock | September 29, 2017 | Subsequent event    
Subsequent Event [Line Items]    
Distributions per share   $ 0.1328125