Document and Entity Information Document - $ / shares	9 Months Ended
	Sep. 27, 2016	Oct. 25, 2016	Dec. 29, 2015
Document Information [Line Items]
Entity Registrant Name	Panera Bread Company
Entity Central Index Key	0000724606
Current Fiscal Year End Date	--12-27
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 27, 2016
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Common Class A [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		21,833,460
Common Stock, Par or Stated Value Per Share	$ 0.0001		$ 0.0001
Common Class B [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		1,381,730
Common Stock, Par or Stated Value Per Share	$ 0.0001		$ 0.0001
Subsequent Event [Member] | Common Class A [Member]
Document Information [Line Items]
Common Stock, Par or Stated Value Per Share		$ 0.0001
Subsequent Event [Member] | Common Class B [Member]
Document Information [Line Items]
Common Stock, Par or Stated Value Per Share		$ 0.0001