XML 83 R73.htm IDEA: XBRL DOCUMENT
v3.23.1

Related Party Transactions - Additional Information (Detail) - USD ($) $ in Millions | 3 Months Ended |
--- | --- | ---
Mar. 31, 2023 | Mar. 31, 2022 | Dec. 31, 2022
Fox Paine Entities |  |  |
Related Party Transaction [Line Items] |  |  |
Company's total voting power | 83.60% |  |
Fox Paine and Company |  |  |
Related Party Transaction [Line Items] |  |  |
Management fees | $ 0.8 | $ 0.7 |
Prepaid management fees | $ 1.3 |  | $ 2.1

X
- Definition Percentage of investee's stock owned by parent + References No definition available. + Details
Name: | gbli_BeneficiallyOwnedSharesParent
Namespace Prefix: | gbli_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Management fees related parties. + References No definition available. + Details
Name: | gbli_ManagementFeesRelatedParties
Namespace Prefix: | gbli_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Prepaid management fee. + References No definition available. + Details
Name: | gbli_PrepaidManagementFee
Namespace Prefix: | gbli_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
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_RelatedPartyTransactionLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=gbli_FoxPaineEntitiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=gbli_FoxPaineAndCompanyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |