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Share-Based Compensation (Details 2) | 12 Months Ended | 26 Months Ended | 56 Months Ended | 108 Months Ended | 12 Months Ended
--- | --- | --- | --- | --- | ---
Jan. 03, 2015 | Apr. 29, 2010 | Mar. 12, 2008 | Jan. 03, 2015 | Jan. 03, 2015 | Dec. 29, 2012
Shares Using Fungibility Ratio |  |  |  |  |  |
Options granted (in shares) | (178,608)us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross |  |  |  |  |
Options forfeited (in shares) | 295,081 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod |  |  |  |  |
2006 Incentive Plan |  |  |  |  |  |
Shares Using Fungibility Ratio |  |  |  |  |  |
Maximum shares of common stock issuable | 4,874,000 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member |  |  | 4,874,000 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member | 4,874,000 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member |
Shares initially reserved for issuance | 500,000 crai_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorizedInitially / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member |  |  | 500,000 crai_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorizedInitially / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member | 500,000 crai_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorizedInitially / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member |
Shares available for grant | 891,352 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member |  |  | 891,352 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member | 891,352 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member |
2006 Incentive Plan | On or after April 30, 2010 |  |  |  |  |  |
Share-based compensation |  |  |  |  |  |
Fungibility ratio (as a percent) | 1.83%crai_ShareBasedCompensationArrangementByShareBasedPaymentAwardFungibilityRatio / us-gaap_AwardDateAxis = crai_ShareBasedCompensationArrangementsActivityPeriodOneMember / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member |  |  |  |  |
2006 Incentive Plan | On or after March 12, 2008 and before April 30, 2010 |  |  |  |  |  |
Share-based compensation |  |  |  |  |  |
Fungibility ratio (as a percent) | 2.20%crai_ShareBasedCompensationArrangementByShareBasedPaymentAwardFungibilityRatio / us-gaap_AwardDateAxis = crai_ShareBasedCompensationArrangementsActivityPeriodTwoMember / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member |  |  |  |  |
2006 Incentive Plan | Before March 12, 2008 |  |  |  |  |  |
Share-based compensation |  |  |  |  |  |
Fungibility ratio (as a percent) | 1.80%crai_ShareBasedCompensationArrangementByShareBasedPaymentAwardFungibilityRatio / us-gaap_AwardDateAxis = crai_ShareBasedCompensationArrangementsActivityPeriodThreeMember / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member |  |  |  |  |
2006 Incentive Plan | Shares approved in 2008 |  |  |  |  |  |
Shares Using Fungibility Ratio |  |  |  |  |  |
Maximum shares of common stock issuable | 210,000 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized / us-gaap_AwardDateAxis = crai_ShareBasedCompensationArrangementsSharesApprovedIn2008Member / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member |  |  | 210,000 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized / us-gaap_AwardDateAxis = crai_ShareBasedCompensationArrangementsSharesApprovedIn2008Member / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member | 210,000 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized / us-gaap_AwardDateAxis = crai_ShareBasedCompensationArrangementsSharesApprovedIn2008Member / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member |
2006 Incentive Plan | Shares approved in 2010 |  |  |  |  |  |
Shares Using Fungibility Ratio |  |  |  |  |  |
Maximum shares of common stock issuable | 1,464,000 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized / us-gaap_AwardDateAxis = crai_ShareBasedCompensationArrangementsSharesApprovedIn2010Member / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member |  |  | 1,464,000 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized / us-gaap_AwardDateAxis = crai_ShareBasedCompensationArrangementsSharesApprovedIn2010Member / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member | 1,464,000 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized / us-gaap_AwardDateAxis = crai_ShareBasedCompensationArrangementsSharesApprovedIn2010Member / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member |
2006 Incentive Plan | Shares approved in 2012 |  |  |  |  |  |
Shares Using Fungibility Ratio |  |  |  |  |  |
Maximum shares of common stock issuable | 2,500,000 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized / us-gaap_AwardDateAxis = crai_ShareBasedCompensationArrangementsSharesApprovedIn2012Member / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member |  |  | 2,500,000 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized / us-gaap_AwardDateAxis = crai_ShareBasedCompensationArrangementsSharesApprovedIn2012Member / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member | 2,500,000 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized / us-gaap_AwardDateAxis = crai_ShareBasedCompensationArrangementsSharesApprovedIn2012Member / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member |
Shares available for grant | 1,700,000 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant / us-gaap_AwardDateAxis = crai_ShareBasedCompensationArrangementsSharesApprovedIn2012Member / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member |  |  | 1,700,000 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant / us-gaap_AwardDateAxis = crai_ShareBasedCompensationArrangementsSharesApprovedIn2012Member / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member | 1,700,000 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant / us-gaap_AwardDateAxis = crai_ShareBasedCompensationArrangementsSharesApprovedIn2012Member / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member |
2006 Incentive Plan | Restricted shares |  |  |  |  |  |
Actual Shares |  |  |  |  |  |
Restricted shares or units granted/reserved |  | 352,932 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGranted / us-gaap_AwardTypeAxis = crai_RestrictedStockAndRestrictedStockUnitAwardsMember / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member | 471,827 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGranted / us-gaap_AwardTypeAxis = crai_RestrictedStockAndRestrictedStockUnitAwardsMember / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member | 1,481,999 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGranted / us-gaap_AwardTypeAxis = crai_RestrictedStockAndRestrictedStockUnitAwardsMember / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member |  |
Cancellation of restricted shares or units |  | 91,964 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsForfeituresAndExpirations / us-gaap_AwardTypeAxis = crai_RestrictedStockAndRestrictedStockUnitAwardsMember / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member | 91,277 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsForfeituresAndExpirations / us-gaap_AwardTypeAxis = crai_RestrictedStockAndRestrictedStockUnitAwardsMember / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member | 470,424 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsForfeituresAndExpirations / us-gaap_AwardTypeAxis = crai_RestrictedStockAndRestrictedStockUnitAwardsMember / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member |  |
Shares Using Fungibility Ratio |  |  |  |  |  |
Restricted shares or units granted/reserved increase (decrease), available for grant |  | (776,450)crai_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsPeriodIncreaseDecreaseGrantedReserved / us-gaap_AwardTypeAxis = crai_RestrictedStockAndRestrictedStockUnitAwardsMember / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member | (849,289)crai_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsPeriodIncreaseDecreaseGrantedReserved / us-gaap_AwardTypeAxis = crai_RestrictedStockAndRestrictedStockUnitAwardsMember / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member | (2,710,594)crai_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsPeriodIncreaseDecreaseGrantedReserved / us-gaap_AwardTypeAxis = crai_RestrictedStockAndRestrictedStockUnitAwardsMember / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member |  |
Cancellation of restricted shares or units increase (decrease), available for grant |  | 202,321 crai_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsPeriodIncreaseDecreaseCancelled / us-gaap_AwardTypeAxis = crai_RestrictedStockAndRestrictedStockUnitAwardsMember / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member | 164,299 crai_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsPeriodIncreaseDecreaseCancelled / us-gaap_AwardTypeAxis = crai_RestrictedStockAndRestrictedStockUnitAwardsMember / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member | 860,877 crai_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsPeriodIncreaseDecreaseCancelled / us-gaap_AwardTypeAxis = crai_RestrictedStockAndRestrictedStockUnitAwardsMember / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member |  |
2006 Incentive Plan | Options |  |  |  |  |  |
Shares Using Fungibility Ratio |  |  |  |  |  |
Options granted (in shares) |  |  |  |  | (1,094,726)us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross / us-gaap_AwardTypeAxis = crai_EmployeeAndDirectorsStockOptionsMember / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member |
Options cancelled (in shares) |  |  |  |  | 193,183 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod / us-gaap_AwardTypeAxis = crai_EmployeeAndDirectorsStockOptionsMember / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member |
Options forfeited (in shares) |  |  |  |  | 27,731 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod / us-gaap_AwardTypeAxis = crai_EmployeeAndDirectorsStockOptionsMember / us-gaap_PlanNameAxis = crai_AmendedAndRestatedEquityIncentivePlan2006Member |
1998 Plan |  |  |  |  |  |
Shares Using Fungibility Ratio |  |  |  |  |  |
Shares available for grant | 1,000,000 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant / us-gaap_PlanNameAxis = crai_IncentiveAndNonqualifiedStockOptionPlan1998Member |  |  | 1,000,000 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant / us-gaap_PlanNameAxis = crai_IncentiveAndNonqualifiedStockOptionPlan1998Member | 1,000,000 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant / us-gaap_PlanNameAxis = crai_IncentiveAndNonqualifiedStockOptionPlan1998Member |
1998 Plan | Options |  |  |  |  |  |
Shares Using Fungibility Ratio |  |  |  |  |  |
Shares available for grant | 0 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant / us-gaap_AwardTypeAxis = crai_EmployeeAndDirectorsStockOptionsMember / us-gaap_PlanNameAxis = crai_IncentiveAndNonqualifiedStockOptionPlan1998Member |  |  | 0 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant / us-gaap_AwardTypeAxis = crai_EmployeeAndDirectorsStockOptionsMember / us-gaap_PlanNameAxis = crai_IncentiveAndNonqualifiedStockOptionPlan1998Member | 0 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant / us-gaap_AwardTypeAxis = crai_EmployeeAndDirectorsStockOptionsMember / us-gaap_PlanNameAxis = crai_IncentiveAndNonqualifiedStockOptionPlan1998Member |
LTIP | Options |  |  |  |  |  |
Shares Using Fungibility Ratio |  |  |  |  |  |
Options granted (in shares) |  |  |  |  |  | 0 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross / us-gaap_AwardTypeAxis = crai_EmployeeAndDirectorsStockOptionsMember / us-gaap_PlanNameAxis = crai_LongtermIncentiveProgramMember

X
- Definition Represents the rate at which each share of the entity's common stock that is underlying any award other than a stock option counts against the maximum number of shares issuable under the share-based compensation plan. + References No definition available. + Details
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- Definition The number of equity-based payment instruments, excluding stock (or unit) options that were cancelled and thus add back to the total shares issuable for purposes of the fungibility ratio. + References No definition available. + Details
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- Definition The number of equity-based payment instruments, excluding stock (or unit) options that were granted or reserve and thus subtract from the total shares issuable for purposes of the fungibility ratio. + References No definition available. + Details
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- Definition Number of shares under non-option equity instrument agreements that were either cancelled or expired. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(iv)(3)-(4) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Net number of non-option equity instruments granted to participants. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(iv)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(iv)(4) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(iv)(3) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Gross number of share options (or share units) granted during the period. + References No definition available. + Details
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