XML 70 R55.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Summary of Business Organization, Operations and Significant Accounting Policies - Accounting Standards Implementation (Details) - USD ($) $ in Millions |  | 12 Months Ended
--- | --- | ---
Jan. 01, 2018 | Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |
Excess tax benefit, amount |  | $ 1.6
Subsequent Event | Accounting Standards Update 2014-09 |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |
Revenue, initial application period cumulative effect transition, reclassifications (less than 2 million annually) | $ 2.0 |

X
- Definition Effective Income Tax Rate Reconciliation, Share-Based Compensation, Excess Tax Benefit, Amount + References No definition available. + Details
Name: | geo_EffectiveIncomeTaxRateReconciliationShareBasedCompensationExcessTaxBenefitAmount
Namespace Prefix: | geo_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Revenue, Initial Application Period Cumulative Effect Transition, Reclassifications + References No definition available. + Details
Name: | geo_RevenueInitialApplicationPeriodCumulativeEffectTransitionReclassifications
Namespace Prefix: | geo_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- 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_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AdjustmentsForNewAccountingPronouncementsAxis=us-gaap_AccountingStandardsUpdate201409Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |