Defined Contribution Benefit Plan Defined Contribution Benefit Plan (Details Textuals) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 30, 2014	Dec. 31, 2013	Dec. 25, 2012
Defined Contribution Pension and Other Postretirement Plans Disclosure [Abstract]
Company Match (as a percent)	50.00%
Match Limit for Employee Pay (as a percent)	3.00%pnra_MatchLimitForEmployeePay
Vesting Percentage (as a percent)	25.00%
Defined Contribution Vesting Period (in years)	5 years
Defined Benefit Plan, Contributions by Employer	$ 2.2	$ 2.0	$ 1.8

The period of time over which the company match vests for the defined contribution plan.

No definition available.

Name:	pnra_DefinedContributionVestingPeriod
Namespace Prefix:	pnra_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The limit the employee can receive a match from the Company on their contributions. This amount is shown as a percentage of the employee's salary.

+ References

No definition available.

+ Details

Name:	pnra_MatchLimitForEmployeePay
Namespace Prefix:	pnra_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_DefinedContributionPensionAndOtherPostretirementPlansDisclosureAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of the cost recognized during the period for defined contribution plans.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 70

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6414718&loc=d3e28014-114942

+ Details

Name:	us-gaap_DefinedContributionPlanCostRecognized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Percentage employer matches of the employee's percentage contribution matched.

+ References

No definition available.

+ Details

Name:	us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of vesting of share-based compensation awards.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration