The additional principal payable amount.

No definition available.

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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

- Definition

Term of the interest rate that fluctuates over time as a result of an underlying benchmark interest rate or index.

+ References

No definition available.

+ Details

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Data Type:	xbrli:durationItemType
Balance Type:	na
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- Definition

Target value to be tested as part of a covenant.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	na
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- Definition

Refers to the fixed charge coverage ratio.

+ References

No definition available.

+ Details

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Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Refers to the leverage ratio.

+ References

No definition available.

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Data Type:	xbrli:pureItemType
Balance Type:	na
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- Definition

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

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- Definition

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

+ References

No definition available.

+ Details

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Data Type:	xbrli:integerItemType
Balance Type:	na
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- Definition

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

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

Name:	gvp_TermLoanAbstract
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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

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Data Type:	num:percentItemType
Balance Type:	na
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- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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

- Definition

Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
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Name:	us-gaap_DeferredFinanceCostsNet
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

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

- References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=118260190&loc=d3e13433-108611

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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 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

Expenses paid for obtaining loans which includes expenses such as application and origination fees.

+ References

No definition available.

+ Details

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

- Definition

The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3213-108585

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

- Definition

The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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-Subparagraph (b)
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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.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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Debt (Details) $ in Thousands			6 Months Ended
Debt (Details) $ in Thousands	Feb. 15, 2019 USD ($)	May 11, 2018 USD ($)	Jun. 30, 2020 USD ($) Letter	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Apr. 17, 2020 USD ($)	Mar. 31, 2020 USD ($)	Jan. 08, 2020 USD ($)	Jan. 06, 2020 USD ($)	Jun. 28, 2019	Dec. 29, 2016 USD ($)
Line of Credit Facility [Abstract]
Fixed charge coverage ratio															1.25
Leverage ratio			2.50									2.75
Number of letters of credit \| Letter			4
Plan [Member]
Line of Credit Facility [Abstract]
Leverage ratio						2.25	2.25	2.25	2.25	2.50
LIBOR [Member]
Term Loan [Abstract]
Term of variable rate			1 month
Citizen's Bank [Member] \| Revolving Credit Facility [Member]
Line of Credit Facility [Abstract]
Line of credit facility expiration period			3 years
Principal amount of the line of credit																$ 5,000
Line of credit facility term			5 years
Outstanding letter of credit balance			$ 3,500
Number of letters of credit \| Letter			4
Outstanding letter of credit balance			$ 1,200
Line of credit facility, remaining borrowing capacity			$ 300
Citizen's Bank [Member] \| Revolving Credit Facility [Member] \| Minimum [Member]
Line of Credit Facility [Abstract]
Percentage of letter of credit fees per annum			1.25%
Citizen's Bank [Member] \| Revolving Credit Facility [Member] \| Maximum [Member]
Line of Credit Facility [Abstract]
Percentage of letter of credit fees per annum			2.00%
Sixth Amendment and Reaffirmation Agreement [Member]
Line of Credit Facility [Abstract]
EBITDA target													$ 4,250
Additional principal payable			$ 500									$ 1,000		$ 3,000
Sixth Amendment and Reaffirmation Agreement [Member] \| Minimum [Member]
Line of Credit Facility [Abstract]
Liquidity													$ 5,000
Seventh Amendment And Reaffirmation Agreement [Member]
Line of Credit Facility [Abstract]
Leverage ratio											1.25
Additional principal payable			500								$ 750
Term Loan [Abstract]
Debt issuance costs			20
Loan origination fees			$ 50
Seventh Amendment And Reaffirmation Agreement [Member] \| Plan [Member]
Line of Credit Facility [Abstract]
Leverage ratio				2.25	2.25	2.25	2.25	2.25	2.50	3.00
Delayed Draw Term Loan [Member] \| Minimum [Member]
Term Loan [Abstract]
Debt instrument, basis spread on variable rate			2.00%
Delayed Draw Term Loan [Member] \| Maximum [Member]
Term Loan [Abstract]
Debt instrument, basis spread on variable rate			2.75%
Delayed Draw Term Loan [Member] \| Citizen's Bank [Member] \| LIBOR [Member]
Term Loan [Abstract]
Term of variable rate			1 month
Delayed Draw Term Loan [Member] \| Citizen's Bank [Member] \| Maximum [Member]
Line of Credit Facility [Abstract]
Line of credit facility expiration period			18 months
Delayed Draw Term Loan [Member] \| Citizen's Bank [Member] \| Revolving Credit Facility [Member]
Line of Credit Facility [Abstract]
Principal amount of the line of credit		$ 25,000
DP Engineering Ltd, CO. [Member]
Term Loan [Abstract]
Cash purchase price	$ 13,500
Proceeds from issuance of debt	14,300
DP Engineering Ltd, CO. [Member] \| Delayed Draw Term Loan [Member]
Line of Credit Facility [Abstract]
Line of credit facility term			5 years
Term Loan [Abstract]
Debt issuance costs	$ 0
DP Engineering Ltd, CO. [Member] \| Delayed Draw Term Loan [Member] \| Minimum [Member]
Term Loan [Abstract]
Debt instrument, basis spread on variable rate	2.00%
DP Engineering Ltd, CO. [Member] \| Delayed Draw Term Loan [Member] \| Maximum [Member]
Term Loan [Abstract]
Debt instrument, basis spread on variable rate	2.75%
True North Consulting, LLC [Member] \| Delayed Draw Term Loan [Member]
Line of Credit Facility [Abstract]
Line of credit facility term			5 years
Term Loan [Abstract]
Proceeds from issuance of debt		10,300
Repayments of debt		500
Debt issuance costs		0
Loan origination fees		$ 75
True North Consulting, LLC [Member] \| Delayed Draw Term Loan [Member] \| LIBOR [Member]
Term Loan [Abstract]
Term of variable rate			1 month
True North Consulting, LLC [Member] \| Delayed Draw Term Loan [Member] \| Citizen's Bank [Member] \| Minimum [Member]
Term Loan [Abstract]
Debt instrument, basis spread on variable rate		2.00%
True North Consulting, LLC [Member] \| Delayed Draw Term Loan [Member] \| Citizen's Bank [Member] \| Maximum [Member]
Term Loan [Abstract]
Debt instrument, basis spread on variable rate		2.75%