Document And Entity Information - shares	3 Months Ended
	Mar. 31, 2024	May 03, 2024
Document Information [Line Items]
Entity Central Index Key	0000712771
Entity Registrant Name	ConnectOne Bancorp, Inc.
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	Q1
Document Fiscal Year Focus	2024
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2024
Document Transition Report	false
Entity File Number	000-11486
Entity Incorporation, State or Country Code	NJ
Entity Tax Identification Number	52-1273725
Entity Address, Address Line One	301 Sylvan Avenue
Entity Address, City or Town	Englewood Cliffs
Entity Address, State or Province	NJ
Entity Address, Postal Zip Code	07632
City Area Code	201
Local Phone Number	816-8900
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		38,333,053
Depositary Shares [Member]
Document Information [Line Items]
Title of 12(b) Security	Depositary Shares (each representing a 1/40th interest in a share of 5.25% Series A Non-Cumulative, perpetual preferred stock)
Trading Symbol	CNOBP
Security Exchange Name	NASDAQ
Common Stock [Member]
Document Information [Line Items]
Title of 12(b) Security	Common stock
Trading Symbol	CNOB
Security Exchange Name	NASDAQ