Cover - shares	3 Months Ended
	Mar. 31, 2020	May 05, 2020
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	000-13396
Entity Registrant Name	CNB FINANCIAL CORP/PA
Entity Central Index Key	0000736772
Entity Incorporation, State or Country Code	PA
Entity Tax Identification Number	25-1450605
Entity Address, Address Line One	1 South Second Street
Entity Address, Address Line Two	P.O. Box 42
Entity Address, City or Town	Clearfield
Entity Address, State or Province	PA
Entity Address, Postal Zip Code	16830
City Area Code	814
Local Phone Number	765-9621
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Title of 12(b) Security	Common Stock, no par value
Trading Symbol	CCNE
Security Exchange Name	NASDAQ
Entity Common Stock, Shares Outstanding (in shares)		15,396,617
Amendment Flag	false