Employee Retirement Plans (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Sep. 27, 2014 item	Sep. 28, 2013	Sep. 29, 2012
United States 401(k) Plan [Member]
Defined Contribution Plan Disclosure [Line Items]
Minimum age of eligible employees	18 years
Minimum hours per week to be eligible for participation in the plan	36
Percentage match of employee contributions	50.00%
Percent of maximum annual contribution per employee	6.00%
Contributions to 401(k) plan	$ 6.4	$ 5.2	$ 4.4
Canadian Group Registered Retirement Savings Plans and Deferred Profit Sharing Plan [Member]
Defined Contribution Plan Disclosure [Line Items]
Contributions to Canadian plans	$ 1.5	$ 1.4	$ 1.0

Represents the minimum age required for an employee to be eligible to participate in the defined contribution plan.

No definition available.

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Namespace Prefix:	gmcr_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the minimum hours per week and employee must work to participate in the defined contribution plan.

+ References

No definition available.

+ Details

Name:	gmcr_DefinedContributionPlanMinimumHoursPerWeekRequirement
Namespace Prefix:	gmcr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of payment into the fund established for purposes of making future disbursements to the individual in accordance with the terms and understanding of the deferred compensation arrangement.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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

- Details

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

- Definition

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

+ References

No definition available.

+ Details

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

- Definition

Maximum percentage of employee gross pay the employee may contribute to a defined contribution plan.

+ References

No definition available.

+ Details

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