Investments - Schedule of Investments (Detail) - USD ($)		6 Months Ended	12 Months Ended
		Jun. 30, 2020	Dec. 31, 2019
Schedule of Investments [Line Items]
Amortized Cost		$ 353,225,888	$ 352,351,819
Fair Value		$ 330,593,500	$ 340,298,376
Percentage of Total Investments		100.00%	100.00%
Senior Secured Term Loans [Member]
Schedule of Investments [Line Items]
Amortized Cost	[1]	$ 99,689,547	$ 83,627,340
Fair Value	[1]	$ 99,415,415	$ 83,353,208
Percentage of Total Investments		30.10%	24.50%
Senior Secured Term Loan Participations [Member]
Schedule of Investments [Line Items]
Amortized Cost	[1]	$ 164,666,560	$ 179,588,536
Fair Value	[1]	$ 158,424,908	$ 180,500,425
Percentage of Total Investments		47.90%	53.00%
Senior Secured Trade Finance Participations [Member]
Schedule of Investments [Line Items]
Amortized Cost	[1]	$ 82,869,781	$ 83,135,943
Fair Value	[1]	$ 67,795,496	$ 71,606,458
Percentage of Total Investments		20.50%	21.00%
Other Investments [Member]
Schedule of Investments [Line Items]
Amortized Cost		$ 6,000,000
Fair Value		$ 3,758,063
Percentage of Total Investments		1.10%
Equity Warrants [Member]
Schedule of Investments [Line Items]
Fair Value		$ 1,199,618	$ 1,080,222
Percentage of Total Investments		0.40%	0.30%
Short Term Investments [Member]
Schedule of Investments [Line Items]
Amortized Cost			$ 6,000,000
Fair Value			$ 3,758,063
Percentage of Total Investments			1.10%

[1] Refer to Notes 2, 3 and 4 of the consolidated financial statements for additional information on the Company’s investments.