Debt (Narrative - Agribusiness And Energy Services Segment) (Details) item in Millions	9 Months Ended
Sep. 30, 2020 USD ($) item	Dec. 31, 2019 USD ($)
Debt Instrument [Line Items]
Short-term notes payable and other borrowings	$ 146,614,000	$ 187,812,000
Agribusiness and Energy Services [Member] \| Green Plains Grain [Member]
Debt Instrument [Line Items]
Minimum working capital required for compliance	$ 18,000,000
Percent Of Sum Of Total Commitment Plus Aggregate Seasonal Line Commitments	18.00%
Minimum Net Worth Required For Compliance, Percent	21.00%
Fixed charge coverage ratio	1.25
Annual leverage ratio	6.00
Maximum Capital Expenditures Per Year Under Agreement	$ 8,000,000.0
Maximum Unused Amounts For Capital Expenditures Under Agreements	8,000,000.0
Agribusiness and Energy Services [Member] \| Green Plains Grain [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 100,000,000.0
Debt Instrument, Maturity Date	Jun. 28, 2022
Additional amounts available under facility, accordion feature	$ 75,000,000.0
Line of credit, maximum borrowing capacity	225,000,000.0
Maximum Long Term Indebtedness Benchmark Under Agreement	$ 10,000,000.0
Maximum Long Term Debt Capitalization Under Agreement	40.00%
Agribusiness and Energy Services [Member] \| Green Plains Grain [Member] \| Revolving Credit Facility [Member] \| LIBOR [Member]
Debt Instrument [Line Items]
Interest rate, basis spread on variable rate, percentage	3.00%
Agribusiness and Energy Services [Member] \| Green Plains Grain [Member] \| Revolving Credit Facility [Member] \| Base Rate [Member]
Debt Instrument [Line Items]
Interest rate, basis spread on variable rate, percentage	2.00%
Agribusiness and Energy Services [Member] \| Green Plains Grain [Member] \| Revolving Credit Facility [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Unused capacity fee, percentage	0.375%
Agribusiness and Energy Services [Member] \| Green Plains Grain [Member] \| Revolving Credit Facility [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Unused capacity fee, percentage	0.50%
Agribusiness and Energy Services [Member] \| Green Plains Grain [Member] \| Seasonal Borrowings [Member]
Debt Instrument [Line Items]
Additional amounts available under facility, accordion feature	$ 50,000,000.0
Agribusiness and Energy Services [Member] \| Green Plains Trade [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Additional amounts available under facility, accordion feature	70,000,000.0
Line of credit, maximum borrowing capacity	300,000,000.0
Minimum working capital required for compliance	$ 1,500,000
Fixed charge coverage ratio	1.15
Allowable dividends as percentage of net profit before taxes	50.00%
Undrawn availability of revolving credit facility on a pro forma basis	$ 10,000,000.0
Availability Benchmark Period Under Agreement	30 days
Unused capacity fee, percentage	0.375%
Agribusiness and Energy Services [Member] \| Green Plains Trade [Member] \| Credit Facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date	Jul. 28, 2022
Line of credit, maximum borrowing capacity	$ 285,000,000
Agribusiness and Energy Services [Member] \| Green Plains Trade [Member] \| Credit Facility [Member] \| LIBOR [Member]
Debt Instrument [Line Items]
Interest rate, basis spread on variable rate, percentage	2.25%
Agribusiness and Energy Services [Member] \| Green Plains Trade [Member] \| First-in-last-out (FILO) Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit, maximum borrowing capacity	$ 15,000,000
Agribusiness and Energy Services [Member] \| Green Plains Trade [Member] \| First-in-last-out (FILO) Credit Facility [Member] \| LIBOR [Member]
Debt Instrument [Line Items]
Interest rate, basis spread on variable rate, percentage	3.25%
Agribusiness and Energy Services [Member] \| Green Plains Commodity Management [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date	Apr. 30, 2023
Line of credit, maximum borrowing capacity	$ 30,000,000.0
Agribusiness and Energy Services [Member] \| Green Plains Commodity Management [Member] \| Revolving Credit Facility [Member] \| LIBOR [Member]
Debt Instrument [Line Items]
Interest rate, basis spread on variable rate, percentage	1.75%
Short-Term Inventory Financing Agreements [Member] \| Agribusiness and Energy Services [Member] \| Green Plains Grain [Member]
Debt Instrument [Line Items]
Number of bushels of corn \| item	1.3
Debt Instrument, Collateral Amount	$ 5,600,000
Short-Term Inventory Financing Agreements [Member] \| Agribusiness and Energy Services [Member] \| Green Plains Grain [Member] \| Significant Other Observable Inputs (Level 2) [Member]
Debt Instrument [Line Items]
Short-term notes payable and other borrowings	$ 5,900,000

Dividends As Percentage Of Net Profit Before Tax

No definition available.

Name:	gpre_AllowableDividendsAsPercentageOfNetProfitBeforeTax
Namespace Prefix:	gpre_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Annual leverage ratio

+ References

No definition available.

+ Details

Name:	gpre_AnnualLeverageRatio
Namespace Prefix:	gpre_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Availability Benchmark Period Under Agreement

+ References

No definition available.

+ Details

Name:	gpre_AvailabilityBenchmarkPeriodUnderAgreement
Namespace Prefix:	gpre_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument Credit Facility Amounts Available Accordion Feature

+ References

No definition available.

+ Details

Name:	gpre_DebtInstrumentCreditFacilityAmountsAvailableAccordionFeature
Namespace Prefix:	gpre_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Fixed Charge Coverage Ratio

+ References

No definition available.

+ Details

Name:	gpre_FixedChargeCoverageRatio
Namespace Prefix:	gpre_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Maximum Capital Expenditures Per Year Under Agreement

+ References

No definition available.

+ Details

Name:	gpre_MaximumCapitalExpendituresPerYearUnderAgreement
Namespace Prefix:	gpre_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Maximum Long Term Debt Capitalization Under Agreement

+ References

No definition available.

+ Details

Name:	gpre_MaximumLongTermDebtCapitalizationUnderAgreement
Namespace Prefix:	gpre_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Maximum Long Term Indebtness Benchmark Under Agreement

+ References

No definition available.

+ Details

Name:	gpre_MaximumLongTermIndebtnessBenchmarkUnderAgreement
Namespace Prefix:	gpre_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum Unused Amounts For Capital Expenditures Under Agreements

+ References

No definition available.

+ Details

Name:	gpre_MaximumUnusedAmountsForCapitalExpendituresUnderAgreements
Namespace Prefix:	gpre_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Minimum Net Worth Required For Compliance, Percent

+ References

No definition available.

+ Details

Name:	gpre_MinimumNetWorthRequiredForCompliancePercent
Namespace Prefix:	gpre_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Working capital - current assets less current liabilities

+ References

No definition available.

+ Details

Name:	gpre_MinimumWorkingCapitalRequiredForCompliance
Namespace Prefix:	gpre_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Number Of Bushels Of Corn

+ References

No definition available.

+ Details

Name:	gpre_NumberOfBushelsOfCorn
Namespace Prefix:	gpre_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Percent Of Sum Of Total Commitment Plus Aggregate Seasonal Line Commitments

+ References

No definition available.

+ Details

Name:	gpre_PercentOfSumOfTotalCommitmentPlusAggregateSeasonalLineCommitments
Namespace Prefix:	gpre_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Undrawn Availability of Revolving Credit Facility On A ProForma Basis

+ References

No definition available.

+ Details

Name:	gpre_UndrawnAvailabilityOfRevolvingCreditFacilityOnProformaBasis
Namespace Prefix:	gpre_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of assets pledged to secure a debt instrument.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

+ Details

Name:	us-gaap_DebtInstrumentCollateralAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

+ Details

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(2))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

+ Details

Name:	us-gaap_DebtInstrumentMaturityDate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

+ References

No definition available.

+ Details

Name:	us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(19)(a))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16)(a)(1))
-URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(13))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

Name:	us-gaap_ShortTermBorrowings
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=gpre_AgribusinessAndEnergyServicesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=gpre_GreenPlainsGrainMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_BaseRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=gpre_SeasonalBorrowingsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=gpre_GreenPlainsTradeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=gpre_CreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=gpre_FirstInLastOutFiloCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=gpre_GreenPlainsCommodityManagementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=gpre_ShortTermInventoryFinancingAgreementsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: