Financing Receivable, Modifications, Accumulated

No definition available.

Name:	krny_FinancingReceivableModificationsAccumulated
Namespace Prefix:	krny_
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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 42
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481962/310-10-50-42

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 42
-Subparagraph (a)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481962/310-10-50-42

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 12A
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481933/310-10-55-12A

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 33
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481962/310-10-50-33

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 34
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481962/310-10-50-34

+ Details

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

- Definition

Number of financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 33
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481962/310-10-50-33

+ Details

Name:	us-gaap_FinancingReceivableModificationsNumberOfContracts2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amortized cost of financing receivable modified during period for debtor experiencing financial difficulty.

+ References

+ Details

Name:	us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount, before troubled debt restructuring, of financing receivable to be modified.

+ References

+ Details

Name:	us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Accumulated amortized cost of financing receivable modified for debtor experiencing financial difficulty.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 42
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481962/310-10-50-42

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 33
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481962/310-10-50-33

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 310
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481746/310-40-50-4

+ Details

Name:	us-gaap_FinancingReceivableModificationsRecordedInvestment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	krny_FinancialInstrumentNonaccrualStatusAxis=krny_AccrualStatusMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	krny_FinancialInstrumentNonaccrualStatusAxis=krny_NonaccrualStatusMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=krny_MultiFamilyMortgageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=krny_NonresidentialMortgageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_CommercialLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ResidentialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_HomeEquityLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

LOANS RECEIVABLE - Troubled Debt Restructurings of Loans Receivable (Details) $ in Thousands	3 Months Ended	9 Months Ended
	Mar. 31, 2023 USD ($) loan	Mar. 31, 2023 USD ($) loan	Jun. 30, 2023 USD ($) loan
Financing Receivable Modifications [Line Items]
Number of TDR defaults \| loan			62
Amount			$ 17,361
Number of TDR defaults \| loan	1	5
Pre- modification Recorded Investment	$ 67	$ 817
Post- modification Recorded Investment	$ 67	$ 814
Accrual
Financing Receivable Modifications [Line Items]
Number of TDR defaults \| loan			54
Amount			$ 10,487
Non-accrual
Financing Receivable Modifications [Line Items]
Number of TDR defaults \| loan			8
Amount			$ 6,874
Commercial
Financing Receivable Modifications [Line Items]
Number of TDR defaults \| loan			13
Amount			$ 9,467
Commercial \| Accrual
Financing Receivable Modifications [Line Items]
Number of TDR defaults \| loan			9
Amount			$ 3,367
Commercial \| Non-accrual
Financing Receivable Modifications [Line Items]
Number of TDR defaults \| loan			4
Amount			$ 6,100
Commercial \| Multi-family mortgage
Financing Receivable Modifications [Line Items]
Number of TDR defaults \| loan			2
Amount			$ 5,400
Commercial \| Multi-family mortgage \| Accrual
Financing Receivable Modifications [Line Items]
Number of TDR defaults \| loan			0
Amount			$ 0
Commercial \| Multi-family mortgage \| Non-accrual
Financing Receivable Modifications [Line Items]
Number of TDR defaults \| loan			2
Amount			$ 5,400
Commercial \| Nonresidential mortgage
Financing Receivable Modifications [Line Items]
Number of TDR defaults \| loan			5
Amount			$ 870
Commercial \| Nonresidential mortgage \| Accrual
Financing Receivable Modifications [Line Items]
Number of TDR defaults \| loan			3
Amount			$ 170
Commercial \| Nonresidential mortgage \| Non-accrual
Financing Receivable Modifications [Line Items]
Number of TDR defaults \| loan			2
Amount			$ 700
Commercial \| Commercial business
Financing Receivable Modifications [Line Items]
Number of TDR defaults \| loan			6
Amount			$ 3,197
Number of TDR defaults \| loan	1	2
Pre- modification Recorded Investment	$ 67	$ 74
Post- modification Recorded Investment	$ 67	$ 74
Commercial \| Commercial business \| Accrual
Financing Receivable Modifications [Line Items]
Number of TDR defaults \| loan			6
Amount			$ 3,197
Commercial \| Commercial business \| Non-accrual
Financing Receivable Modifications [Line Items]
Number of TDR defaults \| loan			0
Amount			$ 0
Residential
Financing Receivable Modifications [Line Items]
Number of TDR defaults \| loan			43
Amount			$ 7,526
Number of TDR defaults \| loan		2
Pre- modification Recorded Investment		$ 708
Post- modification Recorded Investment		$ 705
Residential \| Accrual
Financing Receivable Modifications [Line Items]
Number of TDR defaults \| loan			39
Amount			$ 6,752
Residential \| Non-accrual
Financing Receivable Modifications [Line Items]
Number of TDR defaults \| loan			4
Amount			$ 774
Consumer \| Home equity loans
Financing Receivable Modifications [Line Items]
Number of TDR defaults \| loan			6
Amount			$ 368
Number of TDR defaults \| loan		1
Pre- modification Recorded Investment		$ 35
Post- modification Recorded Investment		$ 35
Consumer \| Home equity loans \| Accrual
Financing Receivable Modifications [Line Items]
Number of TDR defaults \| loan			6
Amount			$ 368
Consumer \| Home equity loans \| Non-accrual
Financing Receivable Modifications [Line Items]
Number of TDR defaults \| loan			0
Amount			$ 0