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Consolidated Schedule of Investments - Investments (Details) (Parentheticals)	Dec. 31, 2022	Dec. 31, 2021
NAV %	226.10%	186.70%
Non-affiliate [Member]
NAV %	226.10%	186.70%
Controlled Affiliate [Member]
NAV %		0.00%
Warrant [Member] | Non-affiliate [Member]
NAV %	9.40%	8.20%
Warrant [Member] | Non-affiliate [Member] | Healthcare Information and Services Segment [Member]
NAV %	0.60%	0.60%
Warrant [Member] | Non-affiliate [Member] | Life Science Segment [Member]
NAV %	3.10%
Warrant [Member] | Non-affiliate [Member] | Life Science [Member]
NAV %		1.00%
Warrant [Member] | Non-affiliate [Member] | Sustainability Segment [Member]
NAV %	0.60%	0.40%
Warrant [Member] | Non-affiliate [Member] | Technology Segment [Member]
NAV %	5.10%	6.20%
Other Long-Term Investments [Member] | Non-affiliate [Member]
NAV %	0.40%	0.10%
Other Long-Term Investments [Member] | Controlled Affiliate [Member] | Biotechnology Sector [Member]
NAV %		0.00%
Equity Securities [Member] | Non-affiliate [Member]
NAV %	0.80%	0.10%
Unrestricted Short Term Investments [Member]
NAV %	2.20%	3.20%
Restricted Short Term Investments [Member]
NAV %	0.90%	0.60%
Debt Investments [Member] | Non-affiliate [Member]
NAV %	215.50%	178.30%
Debt Investments [Member] | Non-affiliate [Member] | Healthcare Information and Services Segment [Member]
NAV %	8.10%	5.00%
Debt Investments [Member] | Non-affiliate [Member] | Life Science Segment [Member]
NAV %		77.30%
Debt Investments [Member] | Non-affiliate [Member] | Life Science [Member]
NAV %	99.70%
Debt Investments [Member] | Non-affiliate [Member] | Sustainability Segment [Member]
NAV %	26.30%	18.80%
Debt Investments [Member] | Non-affiliate [Member] | Technology Segment [Member]
NAV %	81.40%	77.20%

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