INVESTMENT SECURITIES (Details) (USD $)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Investments, Debt and Equity Securities [Abstract]
Reclassification Of Available For Sale Investment Securities To Held To Maturity At Fair Value		$ 138,300,000
Other Asset Impairment Charges	$ 0us-gaap_OtherAssetImpairmentCharges	$ 628,000us-gaap_OtherAssetImpairmentCharges
Number of Investment Securities Sold	54cnob_NumberOfInvestmentSecuritiesSold	170cnob_NumberOfInvestmentSecuritiesSold

The charge against earnings resulting from the write down of long lived assets other than goodwill due to the difference between the carrying value and lower fair value.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6391110&loc=d3e2921-110230

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