Forgivable Loans (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
Oct. 01, 2016	Jan. 02, 2016
Forgivable loans activity
Beginning Balance	$ 44,685	$ 45,356
Advances	5,281	14,531
Repayments	(533)
Amortization	(12,378)	(15,202)
Effect of foreign currency translation	(398)
Ending Balance	36,657	44,685
Current portion of forgivable loans	6,958	4,402
Non-current portion of forgivable loans	$ 29,699	$ 40,283

Represents information pertaining to forgivable loans provided as on the balance sheet date.

No definition available.

No definition available.

Name:	crai_ForgivableLoansActivityAbstract
Namespace Prefix:	crai_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Amounts of increase (decrease) as a result of advances on loans forgivable.

No definition available.

Name:	crai_ForgivableLoansAdvances
Namespace Prefix:	crai_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Represents information pertaining to amortizations on forgivable loans during the period.

No definition available.

Name:	crai_ForgivableLoansAmortization
Namespace Prefix:	crai_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Amounts due on short-term loans forgivable on the balance sheet date.

No definition available.

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

Amounts due on long-term loans forgivable on the balance sheet date.

No definition available.

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

Amount of cash outflow for the repayment of forgivable loan.

No definition available.

Name:	crai_ForgivableLoansRepayments
Namespace Prefix:	crai_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Amounts of increase (decrease) as a result of foreign currency translation on loans forgivable.

No definition available.

Name:	crai_ForgivableLoansTranslationAdjustments
Namespace Prefix:	crai_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration