Annual report pursuant to Section 13 and 15(d)

Subsequent Events - Repurchases of Notes From January 1, 2019 Through Date of Filing (Detail)

v3.19.1
Subsequent Events - Repurchases of Notes From January 1, 2019 Through Date of Filing (Detail) - USD ($)
$ in Thousands
 2 Months Ended 12 Months Ended
Mar. 12, 2019
Dec. 31, 2018
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]    
Cash Paid   $ 15,443
Subsequent Event [Member]    
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]    
Principal Repurchased $ 2,370  
Cash Paid $ 2,168  
Subsequent Event [Member] | Senior Secured Note Period One [Member]    
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]    
Repurchase date Feb. 20, 2019  
Principal Repurchased $ 125  
Cash Paid $ 114  
Percent face value 91.25%  
Bond Issue Costs $ 2  
Net Gain $ 9  
Subsequent Event [Member] | Senior Secured Note Period Two [Member]    
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]    
Repurchase date Feb. 19, 2019  
Principal Repurchased $ 350  
Cash Paid $ 319  
Percent face value 91.25%  
Bond Issue Costs $ 7  
Net Gain $ 24  
Subsequent Event [Member] | Senior Secured Note Period Three [Member]    
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]    
Repurchase date Feb. 12, 2019  
Principal Repurchased $ 1,325  
Cash Paid $ 1,209  
Percent face value 91.25%  
Bond Issue Costs $ 25  
Net Gain $ 91  
Subsequent Event [Member] | Senior Secured Note Period Four [Member]    
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]    
Repurchase date Feb. 10, 2019  
Principal Repurchased $ 570  
Cash Paid $ 526  
Percent face value 92.25%  
Bond Issue Costs $ 9  
Net Gain $ 35