Investment owned, redemption month.

No definition available.

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Namespace Prefix:	ghi_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Mortgage loans on real estate, redemption, face amount.

+ References

No definition available.

+ Details

Name:	ghi_MortgageLoansOnRealEstateRedemptionFaceAmount
Namespace Prefix:	ghi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Maturity date of mortgage loan within investment in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate, in YYYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 12
-Paragraph Column C
-Subsection 29

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 948
-SubTopic 310
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29(Column C))
-URI https://asc.fasb.org/extlink&oid=120402547&loc=d3e617274-123014

+ Details

Name:	srt_MortgageLoanOnRealEstateFinalMaturityDate
Namespace Prefix:	srt_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Interest rate of mortgage loan within investment in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 12
-Paragraph Column B
-Subsection 29

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 948
-SubTopic 310
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29(Column B))
-URI https://asc.fasb.org/extlink&oid=120402547&loc=d3e617274-123014

+ Details

Name:	srt_MortgageLoansOnRealEstateInterestRate
Namespace Prefix:	srt_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of units in a real estate property owned as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfUnitsInRealEstateProperty
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
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

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

- Details

Name:	us-gaap_InvestmentTypeAxis=ghi_MortgageRevenueBondsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ghi_Live929ApartmentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_MortgageLoansOnRealEstateDescriptionLoanCategoryAxis=ghi_TwoThousandFourteenFirstMortgageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementGeographicalAxis=ghi_BaltimoreMdMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_MortgageLoansOnRealEstateDescriptionLoanCategoryAxis=ghi_TwoThousandFourteenSecondMortgageMember
Namespace Prefix:
Data Type:	na
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Mortgage Revenue Bonds - Schedule of Terms of MRBSs upon Redemption (Details) - Mortgage Revenue Bonds [Member]	1 Months Ended
	Jan. 31, 2022 USD ($) Unit	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Schedule Of Available For Sale Securities [Line Items]
Principal Outstanding at Date of Redemption	$ 61,055,000	$ 37,795,376	$ 43,830,074
Live 929 Apartments [Member] \| 2014 Series A [Member] \| Baltimore, MD [Member]
Schedule Of Available For Sale Securities [Line Items]
Month Redeemed	January
Units \| Unit	575
Original Maturity Date	Jul. 01, 2049
Interest Rate	5.78%
Principal Outstanding at Date of Redemption	$ 39,445,000
Live 929 Apartments [Member] \| 2014 Series B [Member] \| Baltimore, MD [Member]
Schedule Of Available For Sale Securities [Line Items]
Month Redeemed	January
Units \| Unit	575
Original Maturity Date	Jul. 01, 2039
Interest Rate	1.60%
Principal Outstanding at Date of Redemption	$ 21,610,000