Contract Assets and Contract Liabilities - Schedule of Costs Estimated Earnings and Billings on Uncompleted Contracts (Details) - USD ($) $ in Thousands	Mar. 30, 2019	Dec. 29, 2018
Contractors [Abstract]
Costs incurred on uncompleted contracts	$ 20,209	$ 34,800
Estimated earnings on uncompleted contracts	4,314	6,921
Earned revenues	24,523	41,721
Less: billings to date	24,533	39,150
Net costs in excess of billings on uncompleted contracts	(10)	2,571
Costs and estimated earnings in excess of billings on uncompleted contracts	2,000	3,175
Billings in excess of costs and estimated earnings on uncompleted contracts	(2,010)	(604)
Net costs in excess of billings on uncompleted contracts	$ (10)	$ 2,571

Costs and estimated earnings in excess of billings on uncompleted contracts.

No definition available.

Name:	ENG_CostsInExcessOfBillingsOnUncompletedContractsCustomerOrProgramsExpectedToBeCollectedWithinOneYear
Namespace Prefix:	ENG_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of receivable reflecting the cost incurred on uncompleted contracts which is expected to be collected within one year or the normal operating cycle, if longer.

+ References

No definition available.

+ Details

Name:	ENG_CostsIncurredOnUncompletedContractsOrProgramsCurrent
Namespace Prefix:	ENG_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of receivable reflecting the estimated earnings (losses) on uncompleted contracts which is expected to be collected within one year or the normal operating cycle, if longer.

+ References

No definition available.

+ Details

Name:	ENG_EstimatedEarningsLossesOnUncompletedContractsOrProgramsCurrent
Namespace Prefix:	ENG_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Net costs and estimated earnings in excess of billings on uncompleted contracts.

+ References

No definition available.

+ Details

Name:	ENG_NetCostsAndEstimatedEarningsInExcessOfBillingsOnUncompletedContracts
Namespace Prefix:	ENG_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.3(c))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable, classified as current.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=118944033&loc=SL49130531-203044

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=118944033&loc=SL49130532-203044

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130549-203045

+ Details

Name:	us-gaap_ContractWithCustomerLiabilityCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- References

No definition available.

+ Details

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

- Definition

Amount to be collected within one year of the balance sheet date (or one operating cycle, if longer) from customers in accordance with the contractual provisions of long-term contracts or programs including amounts billed and unbilled as of the balance sheet date.

+ References

+ Details

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

- 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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 912
-SubTopic 310
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=118261985&loc=d3e55302-109406

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.3(c)(3))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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