XML 235 R100.htm IDEA: XBRL DOCUMENT
v3.25.2

Fair Value Measurements and Fair Value of Financial Instruments - Assets Measured on Recurring Basis (Details) - Recurring [Member] - USD ($) $ in Thousands | Jun. 30, 2025 | Jun. 30, 2024
--- | --- | ---
Fair Value Measurements and Fair Value of Financial Instruments [Abstract] |  |
Securities available-for-sale | $ 356,062 | $ 350,001
Equity securities | 402 | 328
Interest rate swaps | 4,733 | 585
Total | 361,197 | 350,914
Interest rate swaps | 4,733 | 585
Total | 4,733 | 585
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] |  |
Fair Value Measurements and Fair Value of Financial Instruments [Abstract] |  |
Securities available-for-sale | 0 | 0
Equity securities | 402 | 328
Interest rate swaps | 0 | 0
Total | 402 | 328
Interest rate swaps | 0 | 0
Total | 0 | 0
Significant Other Observable Inputs (Level 2) [Member] |  |
Fair Value Measurements and Fair Value of Financial Instruments [Abstract] |  |
Securities available-for-sale | 356,062 | 350,001
Equity securities | 0 | 0
Interest rate swaps | 4,733 | 585
Total | 360,795 | 350,586
Interest rate swaps | 4,733 | 585
Total | 4,733 | 585
Significant Unobservable Inputs (Level 3) [Member] |  |
Fair Value Measurements and Fair Value of Financial Instruments [Abstract] |  |
Securities available-for-sale | 0 | 0
Equity securities | 0 | 0
Interest rate swaps | 0 | 0
Total | 0 | 0
Interest rate swaps | 0 | 0
Total | 0 | 0
U.S. Treasury Securities [Member] |  |
Fair Value Measurements and Fair Value of Financial Instruments [Abstract] |  |
Securities available-for-sale | 10,453 | 41,195
U.S. Treasury Securities [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] |  |
Fair Value Measurements and Fair Value of Financial Instruments [Abstract] |  |
Securities available-for-sale | 0 | 0
U.S. Treasury Securities [Member] | Significant Other Observable Inputs (Level 2) [Member] |  |
Fair Value Measurements and Fair Value of Financial Instruments [Abstract] |  |
Securities available-for-sale | 10,453 | 41,195
U.S. Treasury Securities [Member] | Significant Unobservable Inputs (Level 3) [Member] |  |
Fair Value Measurements and Fair Value of Financial Instruments [Abstract] |  |
Securities available-for-sale | 0 | 0
U.S. Government Sponsored Enterprises [Member] |  |
Fair Value Measurements and Fair Value of Financial Instruments [Abstract] |  |
Securities available-for-sale | 11,644 | 10,974
U.S. Government Sponsored Enterprises [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] |  |
Fair Value Measurements and Fair Value of Financial Instruments [Abstract] |  |
Securities available-for-sale | 0 | 0
U.S. Government Sponsored Enterprises [Member] | Significant Other Observable Inputs (Level 2) [Member] |  |
Fair Value Measurements and Fair Value of Financial Instruments [Abstract] |  |
Securities available-for-sale | 11,644 | 10,974
U.S. Government Sponsored Enterprises [Member] | Significant Unobservable Inputs (Level 3) [Member] |  |
Fair Value Measurements and Fair Value of Financial Instruments [Abstract] |  |
Securities available-for-sale | 0 | 0
State and Political Subdivisions [Member] |  |
Fair Value Measurements and Fair Value of Financial Instruments [Abstract] |  |
Securities available-for-sale | 209,844 | 170,669
State and Political Subdivisions [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] |  |
Fair Value Measurements and Fair Value of Financial Instruments [Abstract] |  |
Securities available-for-sale | 0 | 0
State and Political Subdivisions [Member] | Significant Other Observable Inputs (Level 2) [Member] |  |
Fair Value Measurements and Fair Value of Financial Instruments [Abstract] |  |
Securities available-for-sale | 209,844 | 170,669
State and Political Subdivisions [Member] | Significant Unobservable Inputs (Level 3) [Member] |  |
Fair Value Measurements and Fair Value of Financial Instruments [Abstract] |  |
Securities available-for-sale | 0 | 0
Mortgage-backed Securities-Residential [Member] |  |
Fair Value Measurements and Fair Value of Financial Instruments [Abstract] |  |
Securities available-for-sale | 31,587 | 36,575
Mortgage-backed Securities-Residential [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] |  |
Fair Value Measurements and Fair Value of Financial Instruments [Abstract] |  |
Securities available-for-sale | 0 | 0
Mortgage-backed Securities-Residential [Member] | Significant Other Observable Inputs (Level 2) [Member] |  |
Fair Value Measurements and Fair Value of Financial Instruments [Abstract] |  |
Securities available-for-sale | 31,587 | 36,575
Mortgage-backed Securities-Residential [Member] | Significant Unobservable Inputs (Level 3) [Member] |  |
Fair Value Measurements and Fair Value of Financial Instruments [Abstract] |  |
Securities available-for-sale | 0 | 0
Mortgage-backed Securities-Multi-family [Member] |  |
Fair Value Measurements and Fair Value of Financial Instruments [Abstract] |  |
Securities available-for-sale | 74,597 | 72,300
Mortgage-backed Securities-Multi-family [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] |  |
Fair Value Measurements and Fair Value of Financial Instruments [Abstract] |  |
Securities available-for-sale | 0 | 0
Mortgage-backed Securities-Multi-family [Member] | Significant Other Observable Inputs (Level 2) [Member] |  |
Fair Value Measurements and Fair Value of Financial Instruments [Abstract] |  |
Securities available-for-sale | 74,597 | 72,300
Mortgage-backed Securities-Multi-family [Member] | Significant Unobservable Inputs (Level 3) [Member] |  |
Fair Value Measurements and Fair Value of Financial Instruments [Abstract] |  |
Securities available-for-sale | 0 | 0
Corporate Debt Securities [Member] |  |
Fair Value Measurements and Fair Value of Financial Instruments [Abstract] |  |
Securities available-for-sale | 17,937 | 18,288
Corporate Debt Securities [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] |  |
Fair Value Measurements and Fair Value of Financial Instruments [Abstract] |  |
Securities available-for-sale | 0 | 0
Corporate Debt Securities [Member] | Significant Other Observable Inputs (Level 2) [Member] |  |
Fair Value Measurements and Fair Value of Financial Instruments [Abstract] |  |
Securities available-for-sale | 17,937 | 18,288
Corporate Debt Securities [Member] | Significant Unobservable Inputs (Level 3) [Member] |  |
Fair Value Measurements and Fair Value of Financial Instruments [Abstract] |  |
Securities available-for-sale | $ 0 | $ 0

X
- Definition Fair value portion of asset recognized for present right to economic benefit. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 100 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-100 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_AssetsFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2)(i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 4: http://www.xbrl.org/2003/role/exampleRef -Name Accounting Standards Codification -Section 55 -Paragraph 10 -SubTopic 10 -Topic 825 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482881/825-10-55-10 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 1A -Publisher FASB -URI https://asc.fasb.org/1943274/2147482736/825-10-45-1A Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 11 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-11 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 11 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-11 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 10 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-10 Reference 9: http://www.xbrl.org/2003/role/exampleRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 12 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482881/825-10-55-12 Reference 10: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 103 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-103 Reference 11: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 100 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-100 Reference 12: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 13: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (aa) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-2 Reference 14: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481830/320-10-45-1 Reference 15: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(6)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1 Reference 16: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 30 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479130/326-30-45-1 + Details
Name: | us-gaap_AvailableForSaleSecuritiesDebtSecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2)(i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 1A -Publisher FASB -URI https://asc.fasb.org/1943274/2147482736/825-10-45-1A Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 11 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-11 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 11 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-11 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 10 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-10 Reference 8: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 100 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-100 Reference 9: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 10: http://www.xbrl.org/2003/role/exampleRef -Topic 944 -SubTopic 80 -Name Accounting Standards Codification -Section 55 -Paragraph 14 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480078/944-80-55-14 Reference 11: http://www.xbrl.org/2003/role/exampleRef -Topic 944 -SubTopic 80 -Name Accounting Standards Codification -Section 55 -Paragraph 9 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480078/944-80-55-9 Reference 12: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(1)(b)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1 Reference 13: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(2)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 14: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(1)(6)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1 + Details
Name: | us-gaap_EquitySecuritiesFvNiCurrentAndNoncurrent
Namespace Prefix: | us-gaap_
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 Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 100 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-100 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-3 + Details
Name: | us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Fair value as of the balance sheet date of interest rate derivative assets, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as assets. + References No definition available. + Details
Name: | us-gaap_InterestRateDerivativeAssetsAtFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value as of the balance sheet date of interest rate derivative liabilities, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as liabilities. + References No definition available. + Details
Name: | us-gaap_InterestRateDerivativeLiabilitiesAtFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Fair value of financial and nonfinancial obligations. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_LiabilitiesFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

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

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

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

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