Document and Entity Information - shares	9 Months Ended
	Mar. 29, 2018	Apr. 19, 2018
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 29, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q3
Trading Symbol	JBSS
Entity Registrant Name	SANFILIPPO JOHN B & SON INC
Entity Central Index Key	0000880117
Current Fiscal Year End Date	--06-28
Entity Filer Category	Accelerated Filer
Common Stock, Non-Cumulative Voting Rights of One Vote Per Share [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		8,747,575
Class A Common Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		2,597,426