No definition available.

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

- Definition

Describes the maximum period under which the entity considered its contract receivables to be collected.

+ References

No definition available.

+ Details

Name:	gvp_ContractReceivablePeriodMaximum
Namespace Prefix:	gvp_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Refers to the number of customers that account for contract receivables.

+ References

No definition available.

+ Details

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

- Definition

Amount billed to customers under long-term contracts or programs but not paid. Excludes amounts due that have been withheld because of retainage provisions in a contract.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 910
-SubTopic 310
-Section 50
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-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

For an unclassified balance sheet, a valuation allowance for receivables due a company that are expected to be uncollectible.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Publisher FASB
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-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.4)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_AllowanceForDoubtfulAccountsReceivable
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amounts due for billed services rendered or to be rendered, actions taken or to be taken, or a promise to refrain from taking certain actions in accordance with the terms of a legally binding agreement between the Company and, at a minimum, one other party. An example would be amounts billed to customers under contracts or programs but not paid as of the balance sheet date.

+ References

+ Details

Name:	us-gaap_BilledContractReceivables
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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.

+ References

No definition available.

+ Details

Name:	us-gaap_ConcentrationRiskLineItems
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Balance Type:	na
Period Type:	duration

- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_ContractReceivablesAbstract
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Balance Type:	na
Period Type:	duration

- Definition

The increase (decrease) during the reporting period of the amount of revenue for work performed for which billing has not occurred, net of uncollectible accounts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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-Paragraph 28
-Subparagraph (a)
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Unbilled amounts due for services rendered or to be rendered, actions taken or to be taken, or a promise to refrain from taking certain actions in accordance with the terms of a legally binding agreement between the entity and, at a minimum, one other party. An example would be amounts associated with contracts or programs where the recognized revenue for performance thereunder exceeds the amounts billed under the terms thereof as of the date of the balance sheet.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

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Period Type:

Contract Receivables (Details) $ in Thousands	1 Months Ended	3 Months Ended	12 Months Ended
Contract Receivables (Details) $ in Thousands	Apr. 30, 2016 USD ($)	Mar. 31, 2017 USD ($) Customer	Dec. 31, 2015	Dec. 31, 2016 USD ($) Customer
Contract Receivables [Abstract]
Maximum term of contract receivables		12 months
Components of contract receivables [Abstract]
Billed receivables		$ 5,971		$ 13,325
Recoverable costs and accrued profit not yet billed		7,944		5,555
Allowance for doubtful accounts		(18)		(17)
Total contract receivables, net		$ 13,897		$ 18,863
Unbilled contract receivables billed during October 2016	$ 1,600
Contract Receivable [Member]
Concentration Risk [Line Items]
Number of customers accounting for contract receivables \| Customer		1		0
Percentage of contract receivables accounted by major customers		11.30%	10.00%