Subordinated Debentures (Details) - Jun. 30, 2015 - USD ($)	Total
Subordinated Debentures (Details) [Line Items]
Value of subordinated debentures received by Trust	$ 5,200,000
Percentage Rate Added to Libor	2.85%
Floating interest rate on subordinated debentures	3.13%
Proceeds from Issuance of Debt	$ 50,000,000
Debt Instrument, Term	5 years
Debt Instrument, Maturity Date	Jul. 01, 2025
Debt Instrument, Interest Rate, Stated Percentage	5.75%
Debt Instrument, Description of Variable Rate Basis	three-month LIBOR rate plus 393 basis points
Debt Instrument, Basis Spread on Variable Rate	3.93%
Debt Issuance Cost	$ 900,000
Debt Instrument Weighted Average Period	5 years
Proceeds from Stock Plans	$ 35,000,000
Noncumulative Preferred Stock [Member]
Subordinated Debentures (Details) [Line Items]
Preferred Stock, Value, Outstanding	$ 11,300,000

Debt instrument weighted average period.

No definition available.

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

- Definition

Floating interest rate on subordinated debentures.

+ References

No definition available.

+ Details

Name:	cnob_FloatingInterestRateOnSubordinatedDebentures
Namespace Prefix:	cnob_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage rate added to LIBOR.

+ References

No definition available.

+ Details

Name:	cnob_PercentageRateAddedToLibor
Namespace Prefix:	cnob_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

Name:	cnob_SubordinatedDebenturesDetailsLineItems
Namespace Prefix:	cnob_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Value of subordinated debentures received by Trust.

+ References

No definition available.

+ Details

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

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

+ References

No definition available.

+ Details

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

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

+ Details

Name:	us-gaap_DebtInstrumentMaturityDate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of debt issuance costs (for example, but not limited to, legal, accounting, broker, and regulatory fees).

+ References

No definition available.

+ Details

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

- Definition

Value of all nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer) held by shareholders, which is net of related treasury stock. May be all or a portion of the number of preferred shares authorized. These shares represent the ownership interest of the preferred shareholders.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.28)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 29

-Article 5

+ Details

Name:	us-gaap_PreferredStockValueOutstanding
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

+ References

No definition available.

+ Details

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

- Definition

The cash inflow associated with the amount received from the stock plan during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 14

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3255-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

-URI http://asc.fasb.org/extlink&oid=6513228

+ Details

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

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_NoncumulativePreferredStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: