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Segments - Additional Information (Details)	9 Months Ended
	Sep. 30, 2023 Property Unit Security Segment Bed
Segment Reporting Information [Line Items]
Number of Reportable Segments | Segment	4
Affordable Multifamily Mortgage Revenue Bond Investments Segment [Member]
Segment Reporting Information [Line Items]
Number of Available for Sale Securities | Security	82
Number of available for sale securities in tax-exempt loan | Security	10
Number of Real Estate Properties | Property	2
Seniors and Skilled Nursing Mortgage Revenue Bond Investments Segment [Member]
Segment Reporting Information [Line Items]
Number of rental units financed by mortgage revenue bonds | Bed	294
MF Properties Segment [Member]
Segment Reporting Information [Line Items]
Number of Real Estate Properties | Property	1
Number of rental units under MF properties segment | Unit	384
Residential Properties [Member] | Affordable Multifamily Mortgage Revenue Bond Investments Segment [Member]
Segment Reporting Information [Line Items]
Number of rental units financed by mortgage revenue bonds | Unit	11,325
Number of rental units financed by tax-exempt loan | Unit	1,927
Commercial Real Estate [Member] | Affordable Multifamily Mortgage Revenue Bond Investments Segment [Member]
Segment Reporting Information [Line Items]
Number of collateralized securities | Security	1

X

- Definition

Number of Available for Sale Securities

+ References

No definition available.

+ Details

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X

- Definition

Number of available for sale securities in tax-exempt loan.

+ References

No definition available.

+ Details

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Namespace Prefix:	ghi_
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X

- Definition

Number of collateralized securities.

+ References

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+ Details

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Balance Type:	na
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X

- Definition

Number of rental units financed by mortgage revenue bonds.

+ References

No definition available.

+ Details

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X

- Definition

Number of rental units financed by tax-exempt loan.

+ References

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+ Details

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Data Type:	xbrli:integerItemType
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X

- Definition

Number of rental units under MF properties segment.

+ References

No definition available.

+ Details

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Namespace Prefix:	ghi_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

X

- Definition

The number of real estate properties owned as of the balance sheet date.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 18
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-18

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- 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.

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- Details

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- Details

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X

- Details

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X

- Details

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- Details

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