Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2018	May 04, 2018
Document And Entity Information
Entity Registrant Name	ConnectOne Bancorp, Inc.
Entity Central Index Key	0000712771
Document Type	10-Q
Document Period End Date	Mar. 31, 2018
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		32,184,713
Document Fiscal Period Focus	Q1
Document Fiscal Year Focus	2018