XML 257 R56.htm IDEA: XBRL DOCUMENT
v3.25.1

REGISTRATION STATEMENT AND COMMON EQUITY OFFERINGS (Details) - USD ($) | 12 Months Ended |  |  |  |
--- | --- | --- | --- | --- | ---
Mar. 31, 2025 | Mar. 31, 2024 | Mar. 31, 2023 | May 31, 2024 | Feb. 28, 2024 | Aug. 31, 2022 | Sep. 03, 2021
Government Assistance [Line Items] |  |  |  |  |  |  |
Proceeds from issuance of common stock | $ 2,029,000 | $ 44,508,000 | $ 5,492,000 |  |  |  |
Registration Statement on Form N-2 (File No. 333-277452) |  |  |  |  |  |  |
Government Assistance [Line Items] |  |  |  |  |  |  |
Securities, aggregate value authorized |  |  |  |  | $ 450,000,000.0 |  |
Securities, remaining capacity of aggregate value authorized | 321,500,000 |  |  |  |  |  |
Registration Statement on Form N-2 (File No. 333-259302) |  |  |  |  |  |  |
Government Assistance [Line Items] |  |  |  |  |  |  |
Securities, aggregate value authorized |  |  |  |  |  |  | $ 300,000,000.0
Common Stock ATM Program 2024 |  |  |  |  |  |  |
Government Assistance [Line Items] |  |  |  |  |  |  |
Sale of stock, aggregate offering price authorized |  |  |  | $ 75,000,000.0 |  |  |
Remaining capacity of authorized offering price | $ 73,000,000.0 |  |  |  |  |  |
Common Stock ATM Program |  |  |  |  |  |  |
Government Assistance [Line Items] |  |  |  |  |  |  |
Sale of stock, number of shares sold (in shares) | 148,714 |  |  |  |  |  |
Sale of stock, weighted-average gross price per share (in USD per share) | $ 13.64 |  |  |  |  |  |
Consideration received on transaction | $ 2,000,000.0 |  |  |  |  |  |
Sale of stock, weighted-average net price per share after deducting commissions and offering costs (in USD per share) | $ 13.48 |  |  |  |  |  |
Proceeds from issuance of common stock | $ 2,000,000.0 |  |  |  |  |  |
Common Stock ATM Program 2022 |  |  |  |  |  |  |
Government Assistance [Line Items] |  |  |  |  |  |  |
Sale of stock, aggregate offering price authorized |  |  |  |  |  | $ 50,000,000.0 |
Sale of stock, number of shares sold (in shares) |  | 3,097,162 | 386,482 |  |  |  |
Sale of stock, weighted-average gross price per share (in USD per share) |  | $ 14.37 | $ 14.21 |  |  |  |
Consideration received on transaction |  | $ 44,500,000 | $ 5,500,000 |  |  |  |
Sale of stock, weighted-average net price per share after deducting commissions and offering costs (in USD per share) |  | $ 14.12 | $ 14.01 |  |  |  |
Proceeds from issuance of common stock |  | $ 43,700,000 | $ 5,400,000 |  |  |  |

X
- Definition Sale of Stock, Aggregate Offering Price Authorized + References No definition available. + Details
Name: | gain_SaleOfStockAggregateOfferingPriceAuthorized
Namespace Prefix: | gain_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Sale of Stock, Aggregate Value of Securities Authorized + References No definition available. + Details
Name: | gain_SaleOfStockAggregateValueOfSecuritiesAuthorized
Namespace Prefix: | gain_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Sale of Stock, Remaining Capacity of Aggregate Value of Securities Authorized + References No definition available. + Details
Name: | gain_SaleOfStockRemainingCapacityOfAggregateValueOfSecuritiesAuthorized
Namespace Prefix: | gain_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Sale Of Stock, Remaining Capacity Of Authorized Offering Price + References No definition available. + Details
Name: | gain_SaleOfStockRemainingCapacityOfAuthorizedOfferingPrice
Namespace Prefix: | gain_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Sale of Stock, Weighted-Average Gross Price Per Share + References No definition available. + Details
Name: | gain_SaleOfStockWeightedAverageGrossPricePerShare
Namespace Prefix: | gain_
Data Type: | dtr-types1:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition Sale Of Stock, Weighted-Average Net Price Per Share After Deducting Commissions And Offering Costs + References No definition available. + Details
Name: | gain_SaleOfStockWeightedAverageNetPricePerShareAfterDeductingCommissionsAndOfferingCosts
Namespace Prefix: | gain_
Data Type: | dtr-types1:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 832 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483507/832-10-50-3 + Details
Name: | us-gaap_GovernmentAssistanceLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The cash inflow from the additional capital contribution to the entity. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 45 -Paragraph 14 -Subparagraph (a) -SubTopic 10 -Topic 230 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482740/230-10-45-14 + Details
Name: | us-gaap_ProceedsFromIssuanceOfCommonStock
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Cash received on stock transaction after deduction of issuance costs. + References No definition available. + Details
Name: | us-gaap_SaleOfStockConsiderationReceivedOnTransaction
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The number of shares issued or sold by the subsidiary or equity method investee per stock transaction. + References No definition available. + Details
Name: | us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_SubsidiarySaleOfStockAxis=gain_RegistrationStatementOnFormN2FileNo.333277452Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsidiarySaleOfStockAxis=gain_RegistrationStatementOnFormN2FileNo.333259302Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsidiarySaleOfStockAxis=gain_CommonStockATMProgram2024Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsidiarySaleOfStockAxis=gain_CommonStockATMProgramMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsidiarySaleOfStockAxis=gain_CommonStockATMProgram2022Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |