Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Oct. 30, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	CHEMUNG FINANCIAL CORP
Entity Central Index Key	0000763563
Current Fiscal Year End Date	--12-31
Entity Filer Category	Smaller Reporting Accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding (shares)		4,806,864