Note 5 - Loans and the Allowance for Loan Losses - Loans Modified as TDRs (Details) $ in Thousands	9 Months Ended
Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)
Number of loans	6	18
Pre-modification outstanding recorded investment	$ 10,075	$ 40,270
Post-modification outstanding recorded investment	$ 9,575	$ 40,270
Commercial Portfolio Segment [Member]
Number of loans	2	4
Pre-modification outstanding recorded investment	$ 633	$ 1,276
Post-modification outstanding recorded investment	$ 633	$ 1,276
Commercial Real Estate Portfolio Segment [Member]
Number of loans	2	10
Pre-modification outstanding recorded investment	$ 9,043	$ 35,595
Post-modification outstanding recorded investment	$ 8,543	$ 35,595
Residential Portfolio Segment [Member]
Number of loans	2	3
Pre-modification outstanding recorded investment	$ 399	$ 1,758
Post-modification outstanding recorded investment	$ 399	$ 1,758
Commercial Construction Portfolio Segment [Member]
Number of loans		1
Pre-modification outstanding recorded investment		$ 1,641
Post-modification outstanding recorded investment		$ 1,641

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

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953676-111524

+ Details

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

- Definition

Amount, after troubled debt restructuring, of modified financing receivable.

+ 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

- Details

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

- Details

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