Name:	crai_DebtInstrumentCovenantConsolidatedInterestCoverageRatio
Namespace Prefix:	crai_
Data Type:	xbrli:decimalItemType
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:decimalItemType
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

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

- Details

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

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

No definition available.

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

Amount borrowed under the credit facility as of the balance sheet date.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

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

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.

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(b),22(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

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.