Basis of Presentation and Principles of Consolidation - Concentration of Credit Risks (Details) (Sales, Customer Concentration Risk, Couche-Tard)	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Sales \| Customer Concentration Risk \| Couche-Tard
Concentration Risk [Line Items]
Major customer percentage of net sales	14.50%	14.60%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 21

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-URI http://asc.fasb.org/extlink&oid=35750535&loc=d3e13537-108611

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 275

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

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-Section 50

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-URI http://asc.fasb.org/extlink&oid=35750535&loc=d3e13531-108611

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 275

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-Section 50

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-URI http://asc.fasb.org/extlink&oid=6927468&loc=d3e6351-108592

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