Related Party Transactions - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Related Party Transactions [Abstract]
Aggregate of loans and credit cards total	$ 5,331	$ 4,357
Payments to fund long-term loans to related parties	1,816
Repayment total	667
Net change in outstanding credit card	25
Change in related parties	200
Deposits	$ 11,982	$ 14,434

Deposits received from related parties.

No definition available.

Name:	ccne_DepositsReceivedFromRelatedParties
Namespace Prefix:	ccne_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Payment made to related parties.

+ References

No definition available.

+ Details

Name:	ccne_PaymentMadeToRelatedParties
Namespace Prefix:	ccne_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Related party transaction due from to related party net change in outstanding balance.

+ References

No definition available.

+ Details

Name:	ccne_RelatedPartyTransactionDueFromToRelatedPartyNetChangeInOutstandingBalance
Namespace Prefix:	ccne_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Related party transaction due from to related party removed.

+ References

No definition available.

+ Details

Name:	ccne_RelatedPartyTransactionDueFromToRelatedPartyRemoved
Namespace Prefix:	ccne_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The cash outflow associated with extending a long-term loan to a related party. Alternate caption: Payments for Advances to Affiliates.

+ References

No definition available.

+ Details

Name:	us-gaap_PaymentsToFundLongtermLoansToRelatedParties
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Receivables to be collected from (obligations owed to) related parties, net as of the balance sheet date where one party can exercise control or significant influence over another party; including affiliates, owners or officers and their immediate families, pension trusts, and so forth.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(k)(1))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

Name:	us-gaap_RelatedPartyTransactionDueFromToRelatedParty
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

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