Number of securities holdings.

No definition available.

Name:	ccne_NumberOfSecuritiesHoldings
Namespace Prefix:	ccne_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of securities sold during period.

+ References

No definition available.

+ Details

Name:	ccne_NumberOfSecuritiesSoldDuringPeriod
Namespace Prefix:	ccne_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Shareholders equity percentage.

+ References

No definition available.

+ Details

Name:	ccne_ShareholdersEquityPercentage
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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

This item represents the cost of equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments for other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ References

No definition available.

+ Details

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

- Definition

The cash inflow associated with the sale of debt and equity securities classified as available-for-sale securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Investing Activities
-URI http://asc.fasb.org/extlink&oid=6516133

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=66010992&loc=d3e26853-111562

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (a),(b)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3179-108585

+ Details

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

- Definition

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.

+ References

No definition available.

+ Details

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

- Definition

The fair value of trading securities that serve as collateral for borrowings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5086-111524

+ Details

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

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=ccne_PooledTrustPreferredMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Securities - Additional Information (Detail) $ in Thousands	3 Months Ended			9 Months Ended
Securities - Additional Information (Detail) $ in Thousands	Sep. 30, 2016 USD ($) Securities	Jun. 30, 2016 Securities	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($) Securities	Sep. 30, 2015 USD ($)	Dec. 31, 2015 USD ($) Securities
Schedule of Available-for-sale Securities [Line Items]
Number of securities holdings \| Securities	0			0		0
Shareholders' equity percentage	10.00%			10.00%		10.00%
Proceeds from sale of securities	$ 0		$ 38,025	$ 4,420	$ 86,554
Securities	347,196			347,196		$ 312,669
Pooled Trust Preferred [Member]
Schedule of Available-for-sale Securities [Line Items]
Number of structured pooled trust preferred securities sold \| Securities		2
Amortized cost of securities	1,983			1,983
Proceeds from sale of securities	$ 922			$ 922