Debt instrument agreement notice period.

No definition available.

Name:	geo_DebtInstrumentAgreementNoticePeriod
Namespace Prefix:	geo_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Covenant, Interest Coverage Ratio, Minimum

+ References

No definition available.

+ Details

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Namespace Prefix:	geo_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Covenant, Senior Secured Leverage Ratio, Maximum

+ References

No definition available.

+ Details

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Namespace Prefix:	geo_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Covenant, Total Leverage Ratio, Maximum

+ References

No definition available.

+ Details

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Namespace Prefix:	geo_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Variable Rate, Floor

+ References

No definition available.

+ Details

Name:	geo_DebtInstrumentVariableRateFloor
Namespace Prefix:	geo_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line Of Credit Facility, Accordion Feature, Increase Limit

+ References

No definition available.

+ Details

Name:	geo_LineOfCreditFacilityAccordionFeatureIncreaseLimit
Namespace Prefix:	geo_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Line Of Credit Facility, Additional Increase In Borrowing Capacity

+ References

No definition available.

+ Details

Name:	geo_LineOfCreditFacilityAdditionalIncreaseInBorrowingCapacity
Namespace Prefix:	geo_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Term loans.

+ References

No definition available.

+ Details

Name:	geo_TermLoans
Namespace Prefix:	geo_
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

Amount, before accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=119993939&loc=d3e28555-108399

+ Details

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

- Definition

The percentage points added to the reference rate to compute the variable rate on the interest rate derivative.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeBasisSpreadOnVariableRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 50
-Section 40
-Paragraph 4
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-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585

+ Details

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

- Definition

Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=121555522&loc=d3e12069-110248

+ Details

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

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ 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
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-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

+ Details

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

- 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

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

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

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(3)
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+ Details

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

- Definition

Weighted average interest rate of long-term debt outstanding calculated at point in time.

+ References

No definition available.

+ Details

Name:	us-gaap_LongtermDebtWeightedAverageInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Details

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

- Details

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

- Details

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

- Details

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

- Details

Name:	us-gaap_CreditFacilityAxis=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_CreditFacilityAxis=geo_TermLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_LetterOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=geo_RavenhallMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_CreditFacilityAxis=geo_AccordionMember
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Debt (Amended and Restated Credit Agreement) (Details)		12 Months Ended
Debt (Amended and Restated Credit Agreement) (Details)	Jun. 12, 2019 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2020 AUD ($)	Jun. 12, 2019 AUD ($)
Debt Instrument [Line Items]
Gain (loss) on extinguishment of debt		$ 5,319,000	$ (4,795,000)
Long-term debt		2,935,820,000
Additional increase in borrowing capacity ability		450,000,000.0
Amended and Restated Credit Agreement
Debt Instrument [Line Items]
Gain (loss) on extinguishment of debt	$ (1,200,000)
Debt issuance costs, gross	4,700,000
Revolver
Debt Instrument [Line Items]
Line of credit, amount outstanding		704,400,000
Additional Revolver
Debt Instrument [Line Items]
Borrowing capacity remaining		136,000,000.0
Line of Credit
Debt Instrument [Line Items]
Long-term debt		1,111,339,000
Line of credit, amount outstanding		704,437,000	520,671,000
Term loan		$ 770,000,000	$ 778,000,000
Revolving Credit Facility \| Line of Credit \| Amended and Restated Credit Agreement
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 900,000,000
Maximum borrowing capacity	6.25				6.25
Maximum borrowing capacity	3.50				3.50
Maximum borrowing capacity	3.00				3.00
Weighted average interest rates on outstanding borrowings		2.58%		2.58%
Revolving Credit Facility \| Line of Credit \| Amended and Restated Credit Agreement \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate	2.25%				2.25%
Variable rate, floor	0.00%				0.00%
Term Loan
Debt Instrument [Line Items]
Term loan		$ 770,000,000.0
Term Loan \| Line of Credit \| Amended and Restated Credit Agreement
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 792,000,000.0
Term Loan \| Line of Credit \| Amended and Restated Credit Agreement \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate	2.00%				2.00%
Variable rate, floor	0.75%				0.75%
Letter of credit
Debt Instrument [Line Items]
Long-term debt		59,600,000
Letter of credit \| Revolver \| Ravenhall
Debt Instrument [Line Items]
Maximum exposure, undiscounted		45,500,000		$ 59,000,000
Letter of credit \| Line of Credit \| Amended and Restated Credit Agreement
Debt Instrument [Line Items]
Maximum borrowing capacity					$ 275,000,000
Long-term debt	$ 0
Letter of credit \| Line of Credit \| Bank Guarantee And Standby Sub Facility
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 77,100,000		100,000,000
Debt instrument agreement notice period		90 days
Line of credit, amount outstanding				$ 59,000,000
Accordion \| Line of Credit \| Amended and Restated Credit Agreement
Debt Instrument [Line Items]
Accordion feature, increase limit	$ 450,000,000.0