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Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)
1 Months Ended 3 Months Ended 9 Months Ended
Sep. 30, 2019
Sep. 30, 2019
Sep. 30, 2018
Sep. 30, 2019
Sep. 30, 2018
Accounting Policies [Line Items]          
Dividend payable, amount per share $ 0.03585 $ 0.03585   $ 0.03585  
Dividend payable, date to be paid Oct. 08, 2019        
Dividends Payable, date of record Oct. 02, 2019        
Distributions Paid $ 55,568 $ 250,082 $ 206,624 $ 753,725 $ 381,372
Provision for federal income taxes       $ 0  
Minimum days required to stay for tax liability       183 days  
Sponsor | Professional Fees Liability          
Accounting Policies [Line Items]          
Legal fees and expenses assumed       $ 100,000  
Excess amount of assumed audit fees and legal expenses       $ 100,000