Non-consolidated Variable Interest Entity (Details) $ in Thousands	12 Months Ended
Dec. 31, 2019 USD ($)
Variable Interest Entity [Line Items]
Carrying value	$ 0
DP Engineering Ltd, Co [Member]
Variable Interest Entity [Line Items]
Ownership percentage	48.00%
Contribution amount	$ 48
NXA Consultants LLC [Member]
Variable Interest Entity [Line Items]
Ownership percentage	52.00%
Contribution amount	$ 52

The amount of financial or other support the reporting entity has provided (explicitly or implicitly) to the Variable Interest Entity (VIE) that it was not previously contractually required to provide or that the reporting entity intends to provide, including, for example, situations in which the reporting entity assisted the VIE in obtaining another type of support.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 5A
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=118582676&loc=SL6759159-111685

+ Details

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

- 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

No definition available.

+ Details

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

- Definition

Net carrying amount of the assets and liabilities in the reporting entity's statement of financial position that relate to the reporting entity's variable interest in the Variable Interest Entity (VIE), when the reporting entity is not the VIE's primary beneficiary.

+ References

No definition available.

+ Details

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

- Definition

Percentage of the Variable Interest Entity's (VIE) voting interest owned by (or beneficial interest in) the reporting entity (directly or indirectly).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 5A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=118582676&loc=SL6759159-111685

+ Details

Name:	us-gaap_VariableInterestEntityOwnershipPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	srt_OwnershipAxis=gvp_DPEngineeringLtdCoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_OwnershipAxis=gvp_NXAConsultantsLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: