XML 72 R62.htm IDEA: XBRL DOCUMENT
v3.23.3

Variable Interest Entities - Additional Information (Details) $ in Millions | Sep. 30, 2023 USD ($) Property | Dec. 31, 2022 Property
--- | --- | ---
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Number of Variable Interest Entities | Property | 31 | 35
Investments in Unconsolidated Entities [Member] | Non-Consolidated VIEs [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Maximum exposure to loss, funding commitments | $ 28.5 |
Mortgage Revenue Bonds [Member] | Non-Consolidated VIEs [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Maximum exposure to loss, funding commitments | 99.8 |
Taxable Mortgage Revenue Bonds [Member] | Non-Consolidated VIEs [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Maximum exposure to loss, funding commitments | 19.4 |
Governmental Issuer Loans [Member] | Non-Consolidated VIEs [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Maximum exposure to loss, funding commitments | 56.6 |
Taxable Governmental Issuer Loans [Member] | Non-Consolidated VIEs [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Maximum exposure to loss, funding commitments | 53.6 |
Property Loans [Member] | Non-Consolidated VIEs [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Maximum exposure to loss, funding commitments | $ 31.7 |

X
- Definition The number of variable interest entities owned. + References No definition available. + Details
Name: | ghi_NumberOfVariableInterestEntities
Namespace Prefix: | ghi_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Variable interest entity, maximum loss exposure, funding commitments, amount. + References No definition available. + Details
Name: | ghi_VariableInterestEntityMaximumLossExposureFundingCommitmentsAmount
Namespace Prefix: | ghi_
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_AccountsNotesAndLoansReceivableLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_EquityMethodInvestmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ConsolidatedEntitiesAxis=us-gaap_VariableInterestEntityNotPrimaryBeneficiaryMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InformationByCategoryOfDebtSecurityAxis=us-gaap_AvailableforsaleSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InformationByCategoryOfDebtSecurityAxis=ghi_TaxableMortgageRevenueBondsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InformationByCategoryOfDebtSecurityAxis=ghi_GovernmentalIssuerLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InformationByCategoryOfDebtSecurityAxis=ghi_TaxableGovernmentalIssuerLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InformationByCategoryOfDebtSecurityAxis=ghi_PropertyLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |