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Goodwill (Details) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Goodwill [Line Items]    
Goodwill $ 40,877us-gaap_Goodwill $ 40,877us-gaap_Goodwill
Ethanol Production [Member]    
Goodwill [Line Items]    
Goodwill 30,300us-gaap_Goodwill
/ us-gaap_StatementBusinessSegmentsAxis
= gpre_EthanolProductionMember
 
Marketing And Distribution [Member]    
Goodwill [Line Items]    
Goodwill $ 10,600us-gaap_Goodwill
/ us-gaap_StatementBusinessSegmentsAxis
= gpre_MarketingAndDistributionMember