Investments - Additional Information (Detail)				1 Months Ended						3 Months Ended		6 Months Ended		12 Months Ended
		May 31, 2020 USD ($)	Apr. 07, 2018 USD ($)	Mar. 31, 2020 USD ($)	Jan. 31, 2018 USD ($)	Oct. 31, 2017 USD ($) t	Mar. 31, 2017 USD ($) InterestPayment	Feb. 28, 2017 USD ($)	Oct. 31, 2016 USD ($)	Jun. 30, 2020 USD ($) Investment Contract	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) Investment Contract Land t	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($) Investment	Dec. 31, 2017 USD ($)	Nov. 30, 2019 USD ($)	May 31, 2019 USD ($)	Dec. 06, 2018 USD ($)	Jun. 30, 2018 USD ($)	Apr. 30, 2017 USD ($)	Jan. 31, 2017 USD ($)	May 31, 2016 USD ($)	Jan. 31, 2015 USD ($)
Schedule of Investments [Line Items]
Accrued deferred interest										$ 3,056,770		$ 3,056,770		$ 2,796,466
Accrued interest receivable, description												As such, some of the Company’s trade finance investments have up to a year of accrued interest receivable as of June 30, 2020.
Short term investments maturity period												less than one year
Number of watch list investments | Investment										18		18		13
Interest on loans amount										$ 10,903,460	$ 11,062,607	$ 20,860,302	$ 22,342,110
Net accrued interest										23,957,270		23,957,270		$ 16,501,872
Fair Value										330,593,500		330,593,500		340,298,376
Interest paid												69,290	$ 1,100,154
Itelecom Holding Chile SpA [Member]
Schedule of Investments [Line Items]
Net accrued interest										37,716		37,716
Fair Value										1,408,638		1,408,638
Trade financing participation, principal balance										1,408,638		1,408,638
Senior secured term loans																		$ 8,100,000
Percentage of service rendered for municipalities project											100.00%		100.00%
Collection accounts amounts remains frozen		$ 270,000
Usivale Industria E Commercio Ltda [Member]
Schedule of Investments [Line Items]
Fair Value										2,577,164		2,577,164
Non-Accrual Status [Member]
Schedule of Investments [Line Items]
Unrecorded investment interest income										652,107	$ 1,127,675	2,007,809	$ 2,242,958
Fair Value										15,944,282		15,944,282		38,261,499
Senior Secured Term Loan Participations [Member]
Schedule of Investments [Line Items]
Fair Value	[1]									158,424,908		158,424,908		180,500,425
Senior Secured Term Loan Participations [Member] | Usivale Industria E Commercio Ltda [Member]
Schedule of Investments [Line Items]
Senior secured term loans										2,851,296		2,851,296
Net accrued interest										555,359		555,359
IIG Trade Opportunities Fund B.V. Receivable [Member]
Schedule of Investments [Line Items]
Participation purchases							$ 6,000,000
Number of interest payments received | InterestPayment							3
Loss contingency outstanding amount										35,200,000		35,200,000
IIG Trade Opportunities Fund B.V. Receivable [Member] | Non-Accrual Status [Member]
Schedule of Investments [Line Items]
Unrecorded investment interest income										132,708	132,708	265,416	263,958
Global Pharma Intelligence Sarl [Member]
Schedule of Investments [Line Items]
Net accrued interest										134,215		134,215
Fair Value										648,430		648,430
Trade financing participation, principal balance										648,430		648,430
Global Pharma Intelligence Sarl [Member] | Non-Accrual Status [Member]
Schedule of Investments [Line Items]
Unrecorded investment interest income										23,993	0	53,637	0
Producam SA [Member] | AMC Trade Finance Limited [Member]
Schedule of Investments [Line Items]
Net accrued interest										3,267,506		3,267,506
Fair Value										9,192,637		9,192,637
Trade financing participation, principal balance										10,413,683		10,413,683							$ 15,986,369
Conplex International Ltd. [Member] | TransAsia Private Capital Ltd [Member]
Schedule of Investments [Line Items]
Net accrued interest										1,094,388		1,094,388
Fair Value										7,686,402		7,686,402
Trade financing participation, principal balance										9,500,000		9,500,000
Entire principal amount																	$ 9,500,000
Triton Metallics Pte Ltd [Member] | TransAsia Private Capital Ltd [Member]
Schedule of Investments [Line Items]
Net accrued interest										1,261,647		1,261,647
Fair Value										14,793,124		14,793,124
Trade financing participation, principal balance										16,456,270		16,456,270
Entire principal amount																$ 16,456,270
Helios Maritime I [Member] | Helios Investment Partners, LLP [Member]
Schedule of Investments [Line Items]
Net accrued interest										4,516,047		4,516,047
Fair Value										10,515,861		10,515,861
Trade financing participation, principal balance										12,762,670		12,762,670
Entire principal amount															$ 15,300,000
Deferred interest payable										2,549,918		2,549,918
TRG Cape Verde Holdings Ltd [Member] | Helios Investment Partners, LLP [Member]
Schedule of Investments [Line Items]
Net accrued interest										1,230,971		1,230,971
Fair Value										11,359,874		11,359,874
Trade financing participation, principal balance										13,156,933		13,156,933
Entire principal amount																						$ 17,000,000
Trustco Group Holdings Ltd [Member] | Helios Investment Partners, LLP [Member]
Schedule of Investments [Line Items]
Net accrued interest										1,369,374		1,369,374
Fair Value										14,873,425		14,873,425
Trade financing participation, principal balance										17,176,724		17,176,724
Entire principal amount																					$ 15,000,000
Argentina [Member]
Schedule of Investments [Line Items]
Fair Value										24,159,256		24,159,256		24,198,860
Argentina [Member] | Algodonera Avellaneda S.A [Member]
Schedule of Investments [Line Items]
Participation purchases												$ 6,000,000
Payment of guarantee percentage												100.00%
Litigation amount, plus interest payable												$ 22,400,000
Argentina [Member] | Algodonera Avellaneda S.A [Member] | Non-Accrual Status [Member]
Schedule of Investments [Line Items]
Unrecorded investment interest income										136,500	136,500	273,000	271,500
Argentina [Member] | Frigorifico Regional Industrias Alimentarias S.A. Sucursal Uruguay [Member] | Non-Accrual Status [Member]
Schedule of Investments [Line Items]
Interest on loans amount										$ 261,625	261,625	$ 523,250	520,375
Argentina [Member] | Compania Argentina de Granos [Member]
Schedule of Investments [Line Items]
Participation purchases								$ 2,500,000	$ 10,000,000
Number of export contract | Contract										2		2
Argentina [Member] | Compania Argentina de Granos [Member] | Non-Accrual Status [Member]
Schedule of Investments [Line Items]
Unrecorded investment interest income										$ 0	330,191	$ 330,191	656,754
Argentina [Member] | Sancor Cooperativas Unidas Ltda [Member]
Schedule of Investments [Line Items]
Unrecorded investment interest income										0	0	$ 161,829	0
Extended maturity date												Jul. 29, 2019
Chile [Member]
Schedule of Investments [Line Items]
Fair Value										2,678,224		$ 2,678,224		2,652,855
Chile [Member] | Functional Products Trading S.A [Member]
Schedule of Investments [Line Items]
Unrecorded investment interest income										$ 36,554	0	$ 73,108	0
Extended maturity date												Mar. 04, 2018
Maturity										Dec. 11, 2016		Dec. 11, 2016
Sales declining percentage												57.00%
Morocco [Member]
Schedule of Investments [Line Items]
Fair Value										$ 7,530,616		$ 7,530,616		7,530,616
Morocco [Member] | Scrap Metal Recycler [Member]
Schedule of Investments [Line Items]
Interest on loans amount										0	204,360	204,361	406,475
Net accrued interest										0		0
Trade financing participation, principal balance										7,349,626		$ 7,349,626								$ 9,000,000
Interest paid					$ 330,000
Periodic payment			$ 292,000
Number of unencumbered parcels of land | Land												2
Estimated land value										5,900,000		$ 5,900,000
Morocco [Member] | Scrap Metal Recycler [Member] | Hybrid Income and Collateral Based Approach [Member]
Schedule of Investments [Line Items]
Fair Value										7,530,616		$ 7,530,616
Morocco [Member] | Scrap Metal Recycler [Member] | Copper [Member]
Schedule of Investments [Line Items]
Quantity of primary collateral securing participation, scrap | t												1,970
Shortage of scrap inventory quantity | t						1,820
Scrap collateral value						$ 13,300,000
Procesos Fabriles S.A. [Member]
Schedule of Investments [Line Items]
Interest on loans amount										25,966	27,529	$ 53,495	54,756
Cape Nut [Member] | Barak [Member]
Schedule of Investments [Line Items]
Interest on loans amount										34,761	$ 34,761	69,522	$ 69,140
Fair Value										497,462		497,462
Trade financing participation, principal balance										$ 785,806		$ 785,806											$ 1,250,000
Cape Nut [Member] | Barak [Member] | Extended Maturity [Member]
Schedule of Investments [Line Items]
Ownership percentage held in distributor										50.00%		50.00%
IIG [Member] | Sub-advisory Agreement [Member]
Schedule of Investments [Line Items]
Number of watch list investments | Investment										7		7
Misapplication of investments														$ 6,000,000	6,000,000
Payments for securities and exchange commission				$ 35,200,000
Trade finance securities receivable															$ 6,000,000
Net accrued interest										$ 2,770,705		$ 2,770,705
Fair Value										29,197,409		29,197,409
Trade financing participation, principal balance										41,708,487		41,708,487
IIG [Member] | Sub-advisory Agreement [Member] | Sancor Cooperativas Unidas Ltda [Member] | Hybrid Income and Collateral Based Approach [Member]
Schedule of Investments [Line Items]
Net accrued interest										604,633		604,633
Fair Value										4,719,383		4,719,383
Trade financing participation, principal balance										$ 6,000,000		$ 6,000,000
Maximum [Member]
Schedule of Investments [Line Items]
Accrued interest receivable period												1 year
Trade finance transactions period												180 days
Maximum [Member] | Morocco [Member] | Scrap Metal Recycler [Member]
Schedule of Investments [Line Items]
Loss contingency												$ 40,000,000
Minimum [Member]
Schedule of Investments [Line Items]
Trade finance transactions period												60 days

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