Gladstone Investment Corporation Annual report [Section 13 and 15(d), not S-K Item 405]

Annual report [Section 13 and 15(d), not S-K Item 405]

Cover
- Cover
- Audit Information
Financial Statements
Notes to Financial Statements
Accounting Policies
- SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)
Notes Tables
Notes Details

BORROWINGS - Notes Payable Narrative (Details)

v3.25.1

BORROWINGS - Notes Payable Narrative (Details) - USD ($) $ in Thousands	1 Months Ended
	Dec. 31, 2024	May 31, 2023	Aug. 31, 2021	Mar. 31, 2021	Mar. 31, 2025	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Debt Instrument [Line Items]
Aggregate principal amount				$ 155,434	$ 463,738	$ 404,238	$ 297,688	$ 267,584	$ 54,296	$ 58,096	$ 112,096	$ 74,796	$ 100,096
Notes Payable
Debt Instrument [Line Items]
Aggregate principal amount					$ 463,738	$ 337,238
Notes Payable \| 5.00% Notes Due 2026
Debt Instrument [Line Items]
Interest Rate				5.00%	5.00%	5.00%
Aggregate principal amount				$ 127,900	$ 127,938	$ 127,938
Proceeds from issuance of long-term debt				123,800
Borrowings outstanding at cost				$ 4,100
Notes payable, fair value disclosure					$ 127,500	$ 123,900
Notes Payable \| 4.875% Notes due 2028
Debt Instrument [Line Items]
Interest Rate			4.875%		4.875%	4.875%
Aggregate principal amount			$ 134,600		$ 134,550	$ 134,550
Proceeds from issuance of long-term debt			131,300
Borrowings outstanding at cost			$ 3,300
Notes payable, fair value disclosure					$ 125,000	$ 123,700
Notes Payable \| 8.00% Notes due 2028
Debt Instrument [Line Items]
Interest Rate		8.00%			8.00%	8.00%
Aggregate principal amount		$ 74,800			$ 74,750	$ 74,750
Proceeds from issuance of long-term debt		72,300
Borrowings outstanding at cost		$ 2,500
Notes payable, fair value disclosure					$ 77,500	$ 77,300
Notes Payable \| 7.875% Notes Due 2030
Debt Instrument [Line Items]
Interest Rate	7.875%				7.875%
Aggregate principal amount	$ 126,500				$ 126,500
Proceeds from issuance of long-term debt	122,400
Borrowings outstanding at cost	$ 4,100
Notes payable, fair value disclosure					$ 128,500

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