Derivatives (Details Textual) (Cash Flow Hedging [Member], Commodity Futures Contracts [Member], USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2014
Cash Flow Hedging [Member] \| Commodity Futures Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Cash flow hedge derivative gains (losses) expected to be reclassified into earnings within the next 12 months	$ 3.9

The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=7668309&loc=d3e80748-113994

Name:	us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration