Fair Value Measurements - Summary of Investments Classified as Level 3 (Detail) - USD ($)		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Net change in unrealized appreciation (depreciation) on investments		$ (13,643,894)	$ (15,037,022)
Level 3 [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Investment owned at fair value, beginning balance		287,574,298	340,298,376
Purchases and Transfer of investments		50,466,522	25,495,664	[1]
Maturities or Prepayments of investments		(39,059,632)	(82,513,130)
Accretion of discounts / Payment-in-kind interest		20,275,150	19,330,409
Net change in unrealized appreciation (depreciation) on investments		(13,643,894)	(15,037,022)
Net change in realized appreciation (depreciation) on investments		(4,008,719)
Investment owned at Fair value, ending balance		301,603,725	287,574,298
Level 3 [Member] | Senior Secured Term Loan Participations [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Investment owned at fair value, beginning balance		129,917,253	180,500,425
Purchases and Transfer of investments		37,319,912	1,245,664	[1]
Maturities or Prepayments of investments		(32,173,020)	(52,724,386)
Accretion of discounts / Payment-in-kind interest		7,374,035	7,916,136
Net change in unrealized appreciation (depreciation) on investments		(8,245,871)	(7,020,586)
Net change in realized appreciation (depreciation) on investments		(1,901,566)
Investment owned at Fair value, ending balance		132,290,743	129,917,253
Level 3 [Member] | Senior Secured Trade Finance Participations [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Investment owned at fair value, beginning balance		45,800,210	71,606,458
Purchases and Transfer of investments		3,146,610	(9,456,270)	[1]
Maturities or Prepayments of investments		1,057,070	(13,204,984)
Accretion of discounts / Payment-in-kind interest		1,467,867	3,118,464
Net change in unrealized appreciation (depreciation) on investments		(4,271,915)	(6,263,458)
Net change in realized appreciation (depreciation) on investments		(2,107,153)
Investment owned at Fair value, ending balance		45,092,689	45,800,210
Level 3 [Member] | Other Investments [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Investment owned at fair value, beginning balance		3,758,063	3,758,063
Purchases and Transfer of investments	[1]		4,000,000
Maturities or Prepayments of investments			(4,000,000)
Investment owned at Fair value, ending balance		3,758,063	3,758,063
Level 3 [Member] | Equity Warrants [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Investment owned at fair value, beginning balance		1,199,618	1,080,222
Net change in unrealized appreciation (depreciation) on investments		(111,450)	119,396
Investment owned at Fair value, ending balance		1,088,168	1,199,618
Level 3 [Member] | Senior Secured Term Loans [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Investment owned at fair value, beginning balance		106,899,154	83,353,208
Purchases and Transfer of investments		10,000,000	29,706,270	[1]
Maturities or Prepayments of investments		(7,943,682)	(12,583,759)
Accretion of discounts / Payment-in-kind interest		11,433,248	8,295,809
Net change in unrealized appreciation (depreciation) on investments		(1,014,658)	(1,872,374)
Investment owned at Fair value, ending balance		$ 119,374,062	$ 106,899,154

[1] A restructuring agreement was executed for Triton on August 17, 2020. Under the new agreement, the loan was restructured from a trade finance facility into a term loan.