Number of major customer.

No definition available.

Name:	ctg_NumberOfMajorCustomer
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- Definition

Services agreement expiration date.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (a)
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-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Balance Type:	debit
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.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
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-Publisher FASB
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+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 1
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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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

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- Details

Name:	us-gaap_ConcentrationRiskByBenchmarkAxis=us-gaap_SalesRevenueServicesNetMember
Namespace Prefix:
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Balance Type:
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- Details

Name:	srt_MajorCustomersAxis=ctg_IBMMember
Namespace Prefix:
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Significant Customers - Additional Information (Details) $ in Thousands	3 Months Ended
	Mar. 29, 2019 USD ($) Customer	Mar. 30, 2018 USD ($) Customer	Sep. 29, 2017	Dec. 31, 2018 USD ($)
Segment Reporting Information [Line Items]
Accounts receivable, net	$ 86,606			$ 81,313
Number of major customer \| Customer	0	0
Customer Concentration Risk [Member] \| Sales Revenue, Services, Net [Member]
Segment Reporting Information [Line Items]
Revenue percent	100.00%	100.00%
IBM [Member]
Segment Reporting Information [Line Items]
Revenue	$ 20,900	$ 18,900
Services agreement expiration date			Dec. 31, 2019
Accounts receivable, net	$ 22,800			$ 22,100
IBM [Member] \| Customer Concentration Risk [Member] \| Sales Revenue, Services, Net [Member]
Segment Reporting Information [Line Items]
Revenue percent	21.60%	22.80%