Name:	crai_DebtInstrumentCovenantConsolidatedInterestCoverageRatio
Namespace Prefix:	crai_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

Represents the ratio of consolidated debt to consolidated EBITDA (earnings before interest, taxes, depreciation and amortization) ratio permitted under financial covenants.

No definition available.

Name:	crai_DebtInstrumentCovenantRatioConsolidatedDebtToConsolidatedEBITDA
Namespace Prefix:	crai_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

Represents the percentage of the stock of the entity's domestic subsidiaries pledged as collateral for the credit agreement.

No definition available.

Name:	crai_LineOfCreditFacilityCollateralPercentageOfDomesticSubsidiariesStock
Namespace Prefix:	crai_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

Represents the percentage of the stock of the entity's foreign subsidiaries pledged as collateral for the credit agreement.

No definition available.

Name:	crai_LineOfCreditFacilityCollateralPercentageOfForeignSubsidiariesStock
Namespace Prefix:	crai_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

Represents the value of stock in net assets which is pledged as collateral for the credit agreement.

No definition available.

Name:	crai_LineOfCreditFacilityCollateralValueOfStockInNetAssets
Namespace Prefix:	crai_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Reduction of maximum borrowing capacity under the credit facility.

No definition available.

Name:	crai_LineOfCreditFacilityMaximumBorrowingCapacityReduced
Namespace Prefix:	crai_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

No definition available.

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

No definition available.

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

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.

No definition available.

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

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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

The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

No definition available.

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

Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(19)(a))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(13))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16)(a)(1))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

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

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

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

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

Name:	us-gaap_VariableRateAxis=us-gaap_BaseRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_VariableRateAxis=us-gaap_EurodollarMember
Namespace Prefix:
Data Type:	na
Balance Type:
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