Debt Instrument Denomination integral multiples.

No definition available.

Name:	gecc_DebtInstrumentDenominationIntegralMultiples
Namespace Prefix:	gecc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Debt instrument, minimum denomination.

+ References

No definition available.

+ Details

Name:	gecc_DebtInstrumentMinimumDenomination
Namespace Prefix:	gecc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Debt instrument redemption price of principal amount redeemed.

+ References

No definition available.

+ Details

Name:	gecc_DebtInstrumentRedemptionPriceOfPrincipalAmountRedeemed
Namespace Prefix:	gecc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Line of credit facility commitment maximum borrowing capacity.

+ References

No definition available.

+ Details

Name:	gecc_LineOfCreditFacilityCommitmentMaximumBorrowingCapacity
Namespace Prefix:	gecc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line of credit facility covenant net asset percentage.

+ References

No definition available.

+ Details

Name:	gecc_LineOfCreditFacilityCovenantNetAssetPercentage
Namespace Prefix:	gecc_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line of credit facility covenant net assets.

+ References

No definition available.

+ Details

Name:	gecc_LineOfCreditFacilityCovenantNetAssets
Namespace Prefix:	gecc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Line of credit facility, unused capacity, commitment fee percentage increase decrease.

+ References

No definition available.

+ Details

Name:	gecc_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentageIncreaseDecrease
Namespace Prefix:	gecc_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

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+ Details

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ References

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+ Details

Name:	us-gaap_DebtInstrumentInterestRateEffectivePercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- 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.

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+ Details

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Date when the debt instrument is scheduled to be fully repaid, in YYYY-MM-DD format.

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Name:	us-gaap_DebtInstrumentMaturityDate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of principal amount of debt redeemed.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentRedemptionPricePercentageOfPrincipalAmountRedeemed
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Fair value amount of debt instrument that was repurchased.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentRepurchaseAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

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+ Details

Name:	us-gaap_LineOfCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Date the credit facility terminates, in YYYY-MM-DD format.

+ References

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Name:	us-gaap_LineOfCreditFacilityExpirationDate1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of increase (decrease) of the credit facility.

+ References

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The effective interest rate during the reporting period.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityInterestRateDuringPeriod
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Indebtedness divided by net capital.

+ References

No definition available.

+ Details

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- Details

Name:	us-gaap_LongtermDebtTypeAxis=gecc_MinimumDepositTestNotMetMember
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Debt - Additional Information (Details)							3 Months Ended	6 Months Ended
Debt - Additional Information (Details)	Jul. 20, 2026 USD ($)	May 27, 2026 USD ($)	Aug. 29, 2025 USD ($)	Aug. 13, 2025 USD ($)	Nov. 22, 2023	May 05, 2021 USD ($)	Mar. 31, 2026 USD ($)	Jun. 30, 2026 USD ($)	Jun. 08, 2026	Dec. 31, 2025 USD ($)	Oct. 02, 2025 USD ($)	Sep. 11, 2025 USD ($)	Oct. 03, 2024 USD ($)	Sep. 19, 2024 USD ($)	Jul. 09, 2024 USD ($)	Apr. 25, 2024 USD ($)	Apr. 17, 2024 USD ($)	Aug. 16, 2023 USD ($)	Jul. 09, 2021 USD ($)	Jun. 23, 2021 USD ($)
Debt Instrument [Line Items]
Revolving line of credit borrowings outstanding								$ 11,000,000
Asset coverage ratio								166.4
Unsecured Notes
Debt Instrument [Line Items]
Debt instrument, minimum denomination								$ 25
Debt instrument denomination integral multiples								$ 25
GECCO Notes
Debt Instrument [Line Items]
Debt instrument redemption price of principal amount redeemed		$ 18,600,000					$ 20,000,000
Debt Instrument, aggregate principal amount																			$ 7,500,000	$ 50,000,000
Debt instrument, interest rate																				5.875%
Debt instrument, outstanding principal, repurchased amount							$ 400,000			$ 18,500,000
Percentage of principal amount redeemed							100.00%
GECCZ Notes
Debt Instrument [Line Items]
Debt instrument redemption price of principal amount redeemed			$ 40,000,000
Debt Instrument, aggregate principal amount																		$ 40,000,000
Debt instrument, interest rate																		8.75%
Percentage of principal amount redeemed			100.00%
GECCI Notes
Debt Instrument [Line Items]
Debt Instrument, aggregate principal amount															$ 22,000,000	$ 4,500,000	$ 30,000,000
Debt instrument, interest rate																	8.50%
Maturity date								Apr. 30, 2029
GECCI Notes \| Subsequent Events
Debt Instrument [Line Items]
Debt instrument redemption price of principal amount redeemed	$ 6,500,000
GECCH Notes
Debt Instrument [Line Items]
Debt Instrument, aggregate principal amount													$ 5,400,000	$ 36,000,000
Debt instrument, interest rate														8.125%
Maturity date								Dec. 31, 2029
GECCG Notes
Debt Instrument [Line Items]
Debt Instrument, aggregate principal amount											$ 7,500,000	$ 50,000,000
Debt instrument, interest rate												7.75%
Maturity date								Dec. 31, 2030
Senior Secured Revolving Line of Credit \| Maximum
Debt Instrument [Line Items]
Line of credit facility covenant net assets				$ 80,000,000		$ 80,000,000
Senior Secured Revolving Line of Credit \| Minimum
Debt Instrument [Line Items]
Line of credit facility covenant net assets percentage						150.00%
Senior Secured Revolving Line of Credit \| City National Bank
Debt Instrument [Line Items]
Revolving line of credit commitment maximum borrowing capacity				50,000,000
Revolving line of credit maximum borrowing capacity				90,000,000		$ 25,000,000
Increase revolving credit facility in aggregate amount				$ 40,000,000		$ 25,000,000
Revolving line of credit, maturity date					May 05, 2027	May 05, 2024
Commitment fee percentage for unused portion						0.50%
Commitment fee percentage decreases						0.25%
Revolving line of credit borrowings outstanding								$ 11,000,000
Debt instrument, interest rate				5.875%					8.50%
Senior Secured Revolving Line of Credit \| City National Bank \| Minimum Deposit Test Met \| Share-Based Payment Arrangement, Tranche One [Member]
Debt Instrument [Line Items]
Line of credit interest rate				2.50%
Senior Secured Revolving Line of Credit \| City National Bank \| Minimum Deposit Not Met \| Share-Based Payment Arrangement, Tranche One [Member]
Debt Instrument [Line Items]
Line of credit interest rate				3.50%
Senior Secured Revolving Line of Credit \| City National Bank \| Minimum
Debt Instrument [Line Items]
Line of credit facility covenant net assets percentage						300.00%
Senior Secured Revolving Line of Credit \| City National Bank \| Base Rate \| Minimum Deposit Test Met
Debt Instrument [Line Items]
Line of credit interest rate				1.50%
Senior Secured Revolving Line of Credit \| City National Bank \| Base Rate \| Minimum Deposit Test Not Met
Debt Instrument [Line Items]
Line of credit interest rate				2.50%