Quarterly report pursuant to Section 13 or 15(d)

Equity - Monthly Distributions Declared and Paid by Company's Board of Directors (Detail)

v3.8.0.1
Equity - Monthly Distributions Declared and Paid by Company's Board of Directors (Detail) - $ / shares
 3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Class of Stock [Line Items]    
Distributions per Common Share (in dollars per share) $ 0.13275 $ 0.12900
January    
Class of Stock [Line Items]    
Declaration Date Jan. 09, 2018 Jan. 10, 2017
Record Date Jan. 22, 2018 Jan. 20, 2017
Payment Date Jan. 31, 2018 Jan. 31, 2017
Distributions per Common Share (in dollars per share) $ 0.04425 $ 0.04300
February    
Class of Stock [Line Items]    
Declaration Date Jan. 09, 2018 Jan. 10, 2017
Record Date Feb. 16, 2018 Feb. 16, 2017
Payment Date Feb. 28, 2018 Feb. 28, 2017
Distributions per Common Share (in dollars per share) $ 0.04425 $ 0.04300
March    
Class of Stock [Line Items]    
Declaration Date Jan. 09, 2018 Jan. 10, 2017
Record Date Mar. 20, 2018 Mar. 22, 2017
Payment Date Mar. 30, 2018 Mar. 31, 2017
Distributions per Common Share (in dollars per share) $ 0.04425 $ 0.04300