Note 22 - Quarterly Financial Information of ConnectOne Bancorp, Inc. (Unaudited) - Schedule of Quarterly Financial Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Total interest income	$ 112,469	$ 96,980	$ 85,356	$ 78,941	$ 79,040	$ 77,026	$ 73,051	$ 72,621	$ 373,746	$ 301,738	$ 308,200
Total interest expense	34,460	18,819	9,765	8,583	8,579	8,781	10,042	11,458	71,627	38,860	70,209
Net interest income	78,009	78,161	75,591	70,358	70,461	68,245	63,009	61,163	302,119	262,878	237,991
Provision for credit losses	3,300	10,000	3,000	1,450	815	1,100	(1,649)	(5,766)	17,066	(5,018)	41,000
Total other income	3,508	3,322	3,359	3,054	3,777	4,016	4,472	3,426
Other expenses	33,312	32,143	31,703	29,230	28,084	28,183	26,259	26,485
Income before income tax expense	44,905	39,340	44,247	42,732	45,339	42,978	42,871	43,870	171,224	175,058	90,390
Income tax expense	12,348	10,425	11,889	11,351	12,301	10,881	10,652	10,871	46,013	44,705	19,101
Net income	32,557	28,915	32,358	31,381	33,038	32,097	32,219	32,999	125,211	130,353	71,289
Preferred dividends	1,510	1,509	1,509	1,509	1,717	0	0	0	6,037	1,717	0
Net income available to common stockholders	$ 31,047	$ 27,406	$ 30,849	$ 29,872	$ 31,321	$ 32,097	$ 32,219	$ 32,999	$ 119,174	$ 128,636	$ 71,289
Basic (in dollars per share)	$ 0.79	$ 0.70	$ 0.78	$ 0.76	$ 0.79	$ 0.81	$ 0.81	$ 0.83	$ 3.03	$ 3.24	$ 1.80
Diluted (in dollars per share)	$ 0.79	$ 0.70	$ 0.78	$ 0.75	$ 0.79	$ 0.80	$ 0.81	$ 0.82	$ 3.01	$ 3.22	$ 1.79