Refers to the fixed charge coverage ratio.

No definition available.

Name:	gvp_FixedChargeCoverageRatio
Namespace Prefix:	gvp_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of letter of credit reserved for issuance of new letters under Revolving Line of Credit.

+ References

No definition available.

+ Details

Name:	gvp_LettersOfCreditReservedForIssuance
Namespace Prefix:	gvp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

As part of a covenant the Company agreed to maintain a minimum USA liquidity amount.

+ References

No definition available.

+ Details

Name:	gvp_Liquidity
Namespace Prefix:	gvp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

This item represents the number of letters of credit on which the entity is contingently liable.

+ References

No definition available.

+ Details

Name:	gvp_NumberOfLettersOfCredit
Namespace Prefix:	gvp_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Refers to the percentage of letter of credit fees per annum.

+ References

No definition available.

+ Details

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Namespace Prefix:	gvp_
Data Type:	dtr-types:percentItemType
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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Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- 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.

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

- References

No definition available.

+ Details

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

- Definition

Amount of the fee for available but unused credit capacity under the credit facility.

+ References

+ Details

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

- Definition

Period remaining on line of credit facility before it terminates, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_LineOfCreditFacilityExpirationPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Fair value of the amount outstanding under the credit facility.

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

- 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

+ Details

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

- Definition

Amount of the required periodic payment applied to principal.

+ References

+ Details

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

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

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

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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+ Details

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

- Definition

Amount of cash inflow from contractual arrangement with the lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Name:	us-gaap_ProceedsFromLinesOfCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

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

- Definition

Amount of cash outflow for payment of an obligation from a lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

+ References

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+ Details

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

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
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Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=gvp_NinthAmendmentAndReaffirmationAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementScenarioAxis=us-gaap_ScenarioPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
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Period Type:

Debt (Details) $ in Thousands			3 Months Ended	6 Months Ended		12 Months Ended
Debt (Details) $ in Thousands	May 11, 2018 USD ($)	Dec. 29, 2016 USD ($)	Mar. 29, 2021 USD ($)	Jun. 30, 2021 USD ($) Letter	Jun. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021 USD ($)	Sep. 30, 2021 USD ($)	Mar. 31, 2021 USD ($)
Line of Credit Facility [Abstract]
Repayments of debt						$ 18,500
Repayment on line of credit				$ 1,489	$ 0
Amount drawn on revolving line of credit				800	$ 3,500
Revolving Credit Facility [Member]
Line of Credit Facility [Abstract]
Line of credit facility expiration period		3 years
Line of credit		$ 5,000		3,800
Repayment on line of credit				1,500
Amount drawn on revolving line of credit				800
Long-term debt				$ 2,300
Number of letters of credit \| Letter				3
Outstanding letter of credit balance				$ 933
Amount available at the reporting date				0
Letters of credit reserved for issuance				$ 500
Revolving Credit Facility [Member] \| Minimum [Member]
Line of Credit Facility [Abstract]
Percentage of letter of credit fees per annum						1.25%
Revolving Credit Facility [Member] \| Maximum [Member]
Line of Credit Facility [Abstract]
Percentage of letter of credit fees per annum						2.00%
Ninth Amendment and Reaffirmation Agreement [Member]
Line of Credit Facility [Abstract]
Fixed charge coverage ratio				1.10												1.10
Amendment fee amount						$ 25
Ninth Amendment and Reaffirmation Agreement [Member] \| Plan [Member]
Line of Credit Facility [Abstract]
Fixed charge coverage ratio							2.00	2.00	2.00	2.00	2.00	2.50	2.75	3.00	3.25
Ninth Amendment and Reaffirmation Agreement [Member] \| Revolving Credit Facility [Member]
Line of Credit Facility [Abstract]
Liquidity			$ 2,500
Line of credit				$ 3,750												$ 4,250
Repayment on line of credit			500
Amount available at the reporting date			500
Periodic payment			$ 500
Ninth Amendment and Reaffirmation Agreement [Member] \| Revolving Credit Facility [Member] \| Plan [Member]
Line of Credit Facility [Abstract]
Line of credit															$ 3,500
Amount available at the reporting date														$ 75
Term Loan [Member]
Line of Credit Facility [Abstract]
Line of credit facility expiration period	18 months
Line of credit	$ 25,000
Maturity date	May 11, 2023