Provision for loan losses associated with impacts of the COVID-19 pandemic.

No definition available.

Name:	cnob_AllowanceForLoanLossesIncludedInUnallocated
Namespace Prefix:	cnob_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of deferred loan.

+ References

No definition available.

+ Details

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Namespace Prefix:	cnob_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Loans and the allowance for loan losses details line items.

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Loans performing under the restructured terms

+ References

No definition available.

+ Details

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Namespace Prefix:	cnob_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Non accrual contractual due.

+ References

No definition available.

+ Details

Name:	cnob_NonAccrualContractualDue
Namespace Prefix:	cnob_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of deferred loans.

+ References

No definition available.

+ Details

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

- Definition

Paycheck protection program loans.

+ References

No definition available.

+ Details

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Namespace Prefix:	cnob_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Purchased of credit deteriorated loan.

+ References

No definition available.

+ Details

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Namespace Prefix:	cnob_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Specific allowance of TDR's.

+ References

No definition available.

+ Details

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Namespace Prefix:	cnob_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Reflects the amount of additional interest income that would have been recorded if impaired or nonperforming loans were instead current, in compliance with their original terms, and outstanding throughout the reporting period or since origination (if held for part of the period).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 40
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=121585226&loc=d3e18794-111554

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Carrying amount as of the balance sheet date of loans that have been pledged as collateral for borrowings. If the secured party has the right by contract or custom to sell or re-pledge the collateral, then the debtor reclassifies that asset and report that asset in its statement of financial position separately from other assets not so encumbered.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=66007379&loc=d3e113888-111728

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=123577603&loc=d3e5086-111524

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

For a debtor, the gain (loss) recognized on the transfer of assets, after the impact of income tax expense or benefit, arising from the difference between the book value of the assets transferred before the restructuring and the fair value of the assets transferred.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 60
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6402221&loc=d3e15743-112638

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- Details

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Loans and the Allowance for Credit Losses (Details) $ in Thousands		3 Months Ended	6 Months Ended		12 Months Ended
	Jan. 02, 2021 USD ($)	Jun. 30, 2021 USD ($) Loans	Jun. 30, 2021 USD ($) Loans	Jun. 30, 2020 USD ($)	Dec. 31, 2020 USD ($) Loans
LOANS AND THE ALLOWANCE FOR LOAN LOSSES (Details) [Line Items]
PPP Loans		$ 326,800	$ 326,800		$ 397,500
Non Accrual Contractual Due			90 days
Loans Pledged as Collateral		2,700	$ 2,700		2,700
Provision for credit losses	$ 6,600	$ 1,700	7,000
Loans performing under the restructured terms			33,000		23,700
Loans and Leases Receivable, Impaired, Interest Lost on Nonaccrual Loans			29,400		25,700
Troubled debt restructurings			62,400		$ 49,400
Specific allowance of TDR's			$ 9,200	$ 47
Number of deferred loans \| Loans		79	79		113
Deferred loan		$ 100,020,000	$ 100,020,000		$ 207,000
Special Mention [Member]
LOANS AND THE ALLOWANCE FOR LOAN LOSSES (Details) [Line Items]
Deferred loan		$ 62,000	62,000
90 Days or Greater Past Due and Still Accruing [Member]
LOANS AND THE ALLOWANCE FOR LOAN LOSSES (Details) [Line Items]
Purchased of credit-deteriorated loan			$ 16,400