Document And Entity Information - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2015
Feb. 12, 2016
Jun. 30, 2015
Document And Entity Information [Abstract]      
Document Type 10-K    
Amendment Flag false    
Document Period End Date Dec. 31, 2015    
Document Fiscal Period Focus FY    
Document Fiscal Year Focus 2015    
Entity Registrant Name Green Plains Inc.    
Entity Central Index Key 0001309402    
Current Fiscal Year End Date --12-31    
Entity Filer Category Large Accelerated Filer    
Entity Common Stock, Shares Outstanding   38,474,154  
Entity Well-known Seasoned Issuer Yes    
Entity Public Float     $ 980.0
Entity Current Reporting Status Yes    
Entity Voluntary Filers No    
Trading Symbol gpre