Accounting Policies, by Policy (Policies)	6 Months Ended
Jun. 30, 2015
Accounting Policies [Abstract]
Consolidation, Policy [Policy Text Block]	The consolidated financial statements of ConnectOne Bancorp, Inc. (the “Parent Corporation”) are prepared on an accrual basis and include the accounts of the Parent Corporation and its wholly-owned subsidiary, ConnectOne Bank (the “Bank” and, collectively with the Parent Corporation and the Parent Corporation’s other direct and indirect subsidiaries, the “Company”). All significant intercompany accounts and transactions have been eliminated from the accompanying consolidated financial statements.
Use of Estimates, Policy [Policy Text Block]	In preparing the consolidated financial statements, management has made estimates and assumptions that affect the reported amounts of assets and liabilities as of the dates of the consolidated statements of condition and that affect the results of operations for the periods presented. Actual results could differ significantly from those estimates.
Basis of Accounting, Policy [Policy Text Block]	The consolidated financial statements have been prepared in conformity with U.S. generally accepted accounting principles (“U.S. GAAP”). Some items in the prior year financial statements were reclassified to conform to current presentation. Reclassifications had no effect on prior year net income for stockholders’ equity.
Fair Value of Financial Instruments, Policy [Policy Text Block]	*Fair Value of Financial Instruments* FASB ASC 825-10 requires all entities to disclose the estimated fair value of their financial instrument assets and liabilities. For the Company, as for most financial institutions, the majority of its assets and liabilities are considered financial instruments as defined in FASB ASC 825-10. Many of the Company’s financial instruments, however, lack an available trading market as characterized by a willing buyer and willing seller engaging in an exchange transaction. It is also the Company’s general practice and intent to hold its financial instruments to maturity and not to engage in trading or sales activities except for loans held-for-sale and investment securities available-for-sale. Therefore, significant estimations and assumptions, as well as present value calculations, were used by the Company for the purposes of this disclosure.

Use of Estimates, Policy [Policy Text Block]

In preparing the consolidated financial statements, management has made estimates and assumptions that affect the reported amounts of assets and liabilities as of the dates of the consolidated statements of condition and that affect the results of operations for the periods presented. Actual results could differ significantly from those estimates.

Fair Value of Financial Instruments, Policy [Policy Text Block]

Fair Value of Financial Instruments

FASB ASC 825-10 requires all entities to disclose the estimated fair value of their financial instrument assets and liabilities. For the Company, as for most financial institutions, the majority of its assets and liabilities are considered financial instruments as defined in FASB ASC 825-10. Many of the Company’s financial instruments, however, lack an available trading market as characterized by a willing buyer and willing seller engaging in an exchange transaction. It is also the Company’s general practice and intent to hold its financial instruments to maturity and not to engage in trading or sales activities except for loans held-for-sale and investment securities available-for-sale. Therefore, significant estimations and assumptions, as well as present value calculations, were used by the Company for the purposes of this disclosure.