Contract Receivables (Details) $ in Thousands	1 Months Ended	6 Months Ended	12 Months Ended
Jul. 31, 2018 USD ($)	Jun. 30, 2018 USD ($) Customer	Jun. 30, 2017 USD ($)	Dec. 31, 2017 USD ($) Customer
Contract Receivables [Abstract]
Maximum term of contract receivables		12 months
Components of contract receivables [Abstract]
Billed receivables		$ 9,544		$ 8,154
Unbilled receivables		9,928		5,980
Allowance for doubtful accounts		(251)		(137)
Total contract receivables, net		19,221		$ 13,997
Provision for Doubtful Accounts		117	$ 118
Unbilled contract receivables billed during Oct 2017	$ 3,800	$ (4,121)	$ (3,902)
Contract Receivable [Member]
Concentration Risk [Abstract]
Number of customers accounting for contract receivables \| Customer		1		1
Percentage of contract receivables accounted by major customers		26.60%		26.70%

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

No definition available.

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

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- 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

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Namespace Prefix:	us-gaap_
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

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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

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Period Type:	instant

- 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.

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

- References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Amount of increase (decrease) in obligation to transfer good or service to customer for which consideration has been received or is receivable.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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Balance Type:	debit
Period Type:	duration

- Definition

Amount of expense related to write-down of receivables to the amount expected to be collected. Includes, but is not limited to, accounts receivable and notes receivable.

+ References

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Balance Type:	debit
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

- References

No definition available.

+ Details

Name:	us-gaap_RisksAndUncertaintiesAbstract
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Balance Type:	na
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- 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

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+ Details

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- Details

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