Schedule I - Condensed Financial Information Of The Registrant (Condensed Financial Information Of The Registrant Statements Of Cash Flows - Parent Company Only) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net cash provided (used) by operating activities	$ 221,550	$ 107,336	$ (13,724)
Cash flows from investing activities:
Purchases of property and equipment	(59,547)	(19,764)	(26,776)
Proceeds on disposal of assets, net	9,258	245	117,711
Net cash provided (used) by investing activities	(78,595)	(147,584)	81,447
Cash flows from financing activities:
Proceeds from the issuance of long-term debt	542,692	343,799	73,100
Payments of principal on long-term debt	(557,850)us-gaap_RepaymentsOfLongTermDebt	(303,495)us-gaap_RepaymentsOfLongTermDebt	(120,153)us-gaap_RepaymentsOfLongTermDebt
Payments on short-term borrowings	(3,670,529)us-gaap_RepaymentsOfShortTermDebt	(3,321,556)us-gaap_RepaymentsOfShortTermDebt	(3,249,371)us-gaap_RepaymentsOfShortTermDebt
Payments for repurchase of common stock			(10,445)
Change in restricted cash	(547)gpre_IncreasesDecreasesInRestrictedCash	(1,298)gpre_IncreasesDecreasesInRestrictedCash	(6,196)gpre_IncreasesDecreasesInRestrictedCash
Payment of cash dividends	(8,908)us-gaap_PaymentsOfDividendsCommonStock	(2,426)us-gaap_PaymentsOfDividendsCommonStock
Payments of loan fees	(7,630)us-gaap_PaymentsOfLoanCosts	(10,046)us-gaap_PaymentsOfLoanCosts	(332)us-gaap_PaymentsOfLoanCosts
Proceeds from the exercise of stock options and warrants	4,404	4,498	452
Net cash provided (used) by financing activities	10,528	57,986	11,578
Net change in cash and cash equivalents	153,483	17,738	79,301
Cash and cash equivalents, beginning of period	272,027	254,289	174,988
Cash and cash equivalents, end of period	425,510	272,027	254,289
Green Plains Inc. [Member]
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net cash provided (used) by operating activities	(7,653)	(1,924)	(279)
Cash flows from investing activities:
Purchases of property and equipment	(2,829)	(652)	(616)
Proceeds on disposal of assets, net		42
Investment in subsidiaries	125,179	(53,754)	54,426
Issuance of notes receivable from subsidiaries, net of payments received	9,500	15,356	(6,832)
Other, net	(4,309)	(3,264)	(7,998)
Net cash provided (used) by investing activities	127,541	(42,272)	38,980
Cash flows from financing activities:
Proceeds from the issuance of long-term debt		120,000
Payments of principal on long-term debt	(238)	(1,841)	(204)
Payments on short-term borrowings		(27,162)
Payments for repurchase of common stock			(10,445)
Change in restricted cash	(6,309)
Payment of cash dividends	(8,908)	(2,426)
Payments of loan fees		(5,072)
Proceeds from the exercise of stock options and warrants	4,404	4,498
Other, net			452
Net cash provided (used) by financing activities	(11,051)	87,997	(10,197)
Net change in cash and cash equivalents	108,837	43,801	28,504
Cash and cash equivalents, beginning of period	143,852	100,051	71,547
Cash and cash equivalents, end of period	$ 252,689	$ 143,852	$ 100,051

Schedule I - Condensed Financial Information Of The Registrant (Condensed Financial Information Of The Registrant Statements Of Cash Flows - Parent Company Only) (Details) (USD $)
In Thousands, unless otherwise specified