Document and Entity Information	9 Months Ended
	Sep. 30, 2014	Oct. 15, 2014
Document and Entity Information [Abstract]
Entity Registrant Name	SUFFOLK BANCORP
Entity Central Index Key	0000754673
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		11,667,752
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	Q3
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2014