Loans - Restructured in Troubled Debt (Details) $ in Thousands	3 Months Ended
Mar. 31, 2021 USD ($) loan
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans \| loan	2
Pre-Modification Outstanding Recorded Investment	$ 2,321
Post-Modification Outstanding Recorded Investment	$ 2,321
Multifamily (5 or more) residential properties
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans \| loan	1
Pre-Modification Outstanding Recorded Investment	$ 717
Post-Modification Outstanding Recorded Investment	$ 717
Non-owner occupied, nonfarm nonresidential properties
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans \| loan	1
Pre-Modification Outstanding Recorded Investment	$ 1,604
Post-Modification Outstanding Recorded Investment	$ 1,604

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

+ Details

Name:	us-gaap_FinancingReceivableModificationsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953676-111524

+ Details

Name:	us-gaap_FinancingReceivableModificationsNumberOfContracts2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, after troubled debt restructuring, of modified financing receivable.

+ References

+ Details

Name:	us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount, before troubled debt restructuring, of financing receivable to be modified.

+ References

+ Details

Name:	us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=ccne_MultifamilyResidentialPropertiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=ccne_NonOwnerOccupiedNonfarmNonresidentialPropertiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: