Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2017	Aug. 04, 2017
Document And Entity Information [Abstract]
Trading Symbol	HCKT
Entity Registrant Name	HACKETT GROUP, INC.
Entity Central Index Key	0001057379
Document Type	10-Q
Document Period End Date	Jun. 30, 2017
Amendment Flag	false
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	Q2
Current Fiscal Year End Date	--12-29
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		28,869,509