Document and Entity Information - shares	9 Months Ended
	Oct. 03, 2015	Oct. 29, 2015
Document and Entity Information
Entity Registrant Name	CRA INTERNATIONAL, INC.
Entity Central Index Key	0001053706
Document Type	10-Q
Document Period End Date	Oct. 03, 2015
Amendment Flag	false
Current Fiscal Year End Date	--01-02
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		8,968,298
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q3