XML 57 R46.htm IDEA: XBRL DOCUMENT
v3.5.0.2

Shareholders' Equity - Prospectus Supplement (Details) - USD ($) | 9 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Sep. 30, 2016 | Dec. 31, 2015 | Nov. 10, 2014
Prospectus Supplement July 18, 2014 |  |  |
Class of Stock [Line Items] |  |  |
Common Stock sold under prospectus supplement, in shares | 0 |  |
Prospectus Supplement November 10, 2014 |  |  |
Class of Stock [Line Items] |  |  |
Maximum common stock value authorized under prospectus supplement |  |  | $ 150,000,000
Common Stock sold under prospectus supplement, in shares | 0 | 0 |

X
- Definition Common Stock, Shares, Issued Under Prospectus Supplement + References No definition available. + Details
Name: | geo_CommonStockSharesIssuedUnderProspectusSupplement
Namespace Prefix: | geo_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition MaximumCommonStockValueAuthorizedUnderProspectusSupplement + References No definition available. + Details
Name: | geo_MaximumCommonStockValueAuthorizedUnderProspectusSupplement
Namespace Prefix: | geo_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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

X
- Details
Name: | us-gaap_RegistrationPaymentArrangementByArrangementAxis=geo_ProspectusSupplementJuly182014Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegistrationPaymentArrangementByArrangementAxis=geo_ProspectusSupplementNovember102014Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |