Percentage of annual bonus settled with fully vested restricted stock unit awards

No definition available.

Name:	expo_PercentageOfAnnualBonusSettledWithVestedRestrictedStockUnitAwards
Namespace Prefix:	expo_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Recipient age to expense award on grant date

+ References

No definition available.

+ Details

Name:	expo_ShareBasedAwardsRecipientRetirementAge
Namespace Prefix:	expo_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Share based compensation arrangement by share based payment awards annual vesting percentage.

+ References

No definition available.

+ Details

Name:	expo_ShareBasedCompensationArrangementByShareBasedPaymentAwardsAnnualVestingPercentage
Namespace Prefix:	expo_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Share based compensation arrangements by share based payment award options expiration term.

+ References

No definition available.

+ Details

Name:	expo_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExpirationTerm
Namespace Prefix:	expo_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Stock based compensation, holding period

+ References

No definition available.

+ Details

Name:	expo_VestedRestrictedStockAwardsHoldingPeriod
Namespace Prefix:	expo_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5047-113901

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.F)
-URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)(i)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

+ Details

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

- Definition

Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
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

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

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=expo_VestedRestrictedStockAwardsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=expo_UnvestedRestrictedStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=expo_UnvestedRestrictedStockAwardsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_EmployeeStockOptionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=expo_UnvestedStockOptionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Stock-Based Compensation - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jul. 03, 2020	Jun. 28, 2019	Jul. 03, 2020	Jun. 28, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share Based Compensation Arrangement By Share Based Payment Award Options Expiration Term			10 years
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of annual bonus settled with fully vested restricted stock unit awards			40.00%
Vested Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation, holding period			4 years
Stock based compensation expense	$ 1,799,000	$ 2,325,000	$ 3,842,000	$ 4,393,000
Unvested Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation, vesting period			4 years
Unvested Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expense	1,476,000	1,535,000	$ 5,403,000	5,065,000
Unvested Restricted Stock Awards \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recipient age to expense award on grant date			59 years 6 months
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation, vesting period			4 years
Stock based compensation expense	$ 187,000	$ 150,000	$ 355,000	$ 283,000
Vesting percentage of stock options granted per year			25.00%
Unvested Stock Options [Member] \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recipient age to expense award on grant date			59 years 6 months