The parent entity's majority interest in net assets of the subsidiary, expressed as a percentage.

No definition available.

Name:	sgrp_MajorityInterestOwnershipPercentageByParent
Namespace Prefix:	sgrp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of available field merchandising specialists.

+ References

No definition available.

+ Details

Name:	sgrp_NumberOfMerchandisingSpecialists
Namespace Prefix:	sgrp_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of full-time national, regional, and district administrators.

+ References

No definition available.

+ Details

Name:	sgrp_NumberOfNationalRegionalAndDistrictAdministrators
Namespace Prefix:	sgrp_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents number of specialist provided by a related party.

+ References

No definition available.

+ Details

Name:	sgrp_NumberOfSpecialistsProvidedByRelatedParty
Namespace Prefix:	sgrp_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents number of vehicles leased under lease arrangement.

+ References

No definition available.

+ Details

Name:	sgrp_NumberOfVehiclesLeased
Namespace Prefix:	sgrp_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents number of vehicles subleased.

+ References

No definition available.

+ Details

Name:	sgrp_NumberOfVehiclesSubleased
Namespace Prefix:	sgrp_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Percent of service provided by related party.

+ References

No definition available.

+ Details

Name:	sgrp_PercentOfServiceProvidedByRelatedParty
Namespace Prefix:	sgrp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of ownership by a related person in a related entity.

+ References

No definition available.

+ Details

Name:	sgrp_RelatedPartyOwnershipPercentage
Namespace Prefix:	sgrp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Term of the lessee's leasing arrangement, 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_LesseeLeasingArrangementsOperatingLeasesTermOfContract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

+ References

No definition available.

+ Details

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

- Definition

The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

+ References

No definition available.

+ Details

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

- Definition

The cash outflow from advancing money to an affiliate (an entity that is related but not strictly controlled by the entity).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Investing Activities
-URI http://asc.fasb.org/extlink&oid=6516133

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3213-108585

+ Details

Name:	us-gaap_PaymentsForAdvanceToAffiliate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash inflow from the collection of money previously advanced to an entity that is related to it but not strictly controlled.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3179-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Investing Activities
-URI http://asc.fasb.org/extlink&oid=6516133

+ Details

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

- Definition

Amount of transactions with related party during the financial reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39603-107864

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39622-107864

+ Details

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

- Definition

Expenses recognized resulting from transactions (excluding transactions that are eliminated in consolidated or combined financial statements) with related party.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864

+ Details

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

- Definition

Identify the stated interest rate per the agreement, for example, leasing and debt arrangements between related parties.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=sgrp_SasMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionAxis=sgrp_DomesticFieldManagementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=sgrp_SBSMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionAxis=sgrp_DomesticMerchandisingSpecialistsFieldForceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementScenarioAxis=sgrp_CostPlusFeeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=sgrp_SbsAndSasMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=sgrp_NMSMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=sgrp_DomesticMerchandisingSpecialistsFieldForceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionAxis=sgrp_NRSMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=sgrp_NRSMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionAxis=sgrp_Plus2CompensationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=sgrp_CMRMeridienMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LeaseArrangementTypeAxis=sgrp_LeaseArrangementWithMcptMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=sgrp_MrBrianMasonMrGarryBristowAndMrAdrianWingfieldMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=sgrp_MrMasonMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=sgrp_NDSMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=sgrp_MrAndMsYilmazMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=sgrp_SPARTodopromoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=sgrp_MrJuanFMedinaDomenzainMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=sgrp_CONMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=sgrp_AffinityInsuranceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Note 10 - Related-Party Transactions (Details Textual)		3 Months Ended	12 Months Ended
Note 10 - Related-Party Transactions (Details Textual)	Jan. 01, 2004	Dec. 31, 2015 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
SAS [Member] \| Domestic Field Management [Member]
Percent Of Service Provided By Related Party			92.00%	92.00%
SBS [Member] \| Domestic Merchandising Specialists Field Force [Member]
Percent Of Service Provided By Related Party			82.00%	81.00%
SBS [Member] \| Cost Plus Fee [Member]
Related Party Transaction, Rate			2.96%
SBS [Member]
Number of Merchandising Specialists			7,300
Number of National, Regional, and District Administrators			57
SBS And SAS [Member] \| Domestic Field Management [Member]
Related Party Transaction, Expenses from Transactions with Related Party			$ 25,700,000	$ 26,900,000
SBS And SAS [Member] \| Cost Plus Fee [Member]
Related Party Transaction, Rate	4.00%
N M S [Member]
Majority Interest Ownership Percentage By Parent		51.00%	51.00%
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners		49.00%	49.00%
Payments for Advance to Affiliate		$ 418,000
Proceeds from Collection of Advance to Affiliate		$ 2,016
Domestic Merchandising Specialists Field Force [Member] \| NRS [Member]
Number Of Specialists Provided By Related Party			700
NRS [Member] \| Domestic Merchandising Specialists Field Force [Member]
Percent Of Service Provided By Related Party			5.00%	8.00%
NRS [Member] \| Plus2 Compensation [Member]
Related Party Transaction, Rate			2.00%
Related Party Transaction, Amounts of Transaction			$ 26,000	$ 44,000
C M R Meridien [Member] \| Lease Arrangement With MCPT [Member]
Number Of Vehicles Subleased			2
Number Of Vehicles Leased			126
Lessee Leasing Arrangements, Operating Leases, Term of Contract			4 years
C M R Meridien [Member]
Majority Interest Ownership Percentage By Parent		51.00%	51.00%
Mr. Brian Mason Mr. Garry Bristow And Mr. Adrian Wingfield [Member]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners		49.00%	49.00%
Mr. Mason [Member]
Related Party Ownership Percentage			50.00%
NDS [Member]
Majority Interest Ownership Percentage By Parent		51.00%	51.00%
Mr And Ms Yilmaz [Member]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners		49.00%	49.00%
Related Party Ownership Percentage			40.00%
SPAR Todopromo [Member]
Majority Interest Ownership Percentage By Parent		51.00%	51.00%
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners		49.00%	49.00%
Mr. Juan F. Medina Domenzain [Member] \| CON [Member]
Related Party Ownership Percentage			90.00%
Affinity Insurance [Member] \| Maximum [Member]
Noncontrolling Interest, Ownership Percentage by Parent		1.00%	1.00%
Related Party Transaction, Expenses from Transactions with Related Party			$ 28,036,000	$ 30,237,000