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

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+ Details

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

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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-Paragraph 1
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+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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Balance Type:	na
Period Type:	duration

- References

No definition available.

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

- References

No definition available.

+ Details

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

- Definition

Reflects the estimated amount of loss from the specified contingency as of the balance sheet date.

+ References

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

- Details

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

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
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Balance Type:
Period Type:

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Subsequent Events (Details) - USD ($) $ in Thousands	3 Months Ended
Subsequent Events (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Jul. 14, 2020	Apr. 24, 2020
Line of Credit Facility [Abstract]
Face amount	$ 10,000
Paycheck Protection Program [Member]
Line of Credit Facility [Abstract]
Maturity date	Apr. 24, 2022
Subsequent Event [Member] \| Minimum [Member]
Loss Contingency, Estimate [Abstract]
Estimated gross settlement		$ 861
Subsequent Event [Member] \| Maximum [Member]
Loss Contingency, Estimate [Abstract]
Estimated gross settlement		$ 1,500
Subsequent Event [Member] \| Paycheck Protection Program [Member]
Line of Credit Facility [Abstract]
Interest rate			0.98%
Face amount			$ 10,000