Employee Benefit Plans - Additional Information (Detail) $ in Thousands	12 Months Ended
Dec. 31, 2015 USD ($) Services Age	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee pretax contribution percentage	100.00%
Employees compensation	50.00%
Corporation's matching contribution and related expenses	$ 508	$ 620	$ 431
Profit sharing contributions	6.00%
Compensation percentage in excess of specified amount	5.70%
Excess of compensation	$ 119
Recognized profit sharing expense	868	1,044	855
Obligations of other liabilities	4,666	4,316
Expenses related employee benefit plans	608	454	541
Obligations under survivor benefit plan	1,142	987
Other liabilities related to survivor benefit plan	$ 155	55	$ 119
Employee retirement health care benefits plan \| Age	60
Minimum service period for participation in benefit plan \| Services	30
Accumulated benefit obligation	$ 3,066	$ 2,744
Amortized from accumulated other comprehensive income into net periodic benefit cost	$ 184
Weighted average discount rate net periodic benefit cost	3.42%	4.31%	3.88%
Weighted average rate accrued benefit obligations	3.67%	3.42%	4.31%
Expected costs of benefit	5.00%
Percent rate of increase in the health care trend	1.00%
Increase in health care trend rates	$ 300
Increase service and interest costs	$ 24
Percent rate of decrease in the health care trend	1.00%
Decrease in health care trend rates	$ 267
Decrease service and interest costs	$ 21
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee contribution percentage	1.00%
Total contributed by employee percentage	1.00%
Qualifying dependents age group \| Age	60
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee contribution percentage	3.00%
Total contributed by employee percentage	4.00%
Qualifying dependents age group \| Age	65

Amortized from accumulated other comprehensive income into net periodic benefit cost.

No definition available.

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

- Definition

Compensation percentage in excess of specified amount.

+ References

No definition available.

+ Details

Name:	ccne_CompensationPercentageInExcessOfSpecifiedAmount
Namespace Prefix:	ccne_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Defined benefit plan compensation by employer.

+ References

No definition available.

+ Details

Name:	ccne_DefinedBenefitPlanCompensationByEmployer
Namespace Prefix:	ccne_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Employee Benefit Plans Contribution By Employee Percentage

+ References

No definition available.

+ Details

Name:	ccne_EmployeeBenefitPlansContributionByEmployeePercentage
Namespace Prefix:	ccne_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Excess specified compensation.

+ References

No definition available.

+ Details

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

- Definition

Expenses related to supplemental executive retirement plan.

+ References

No definition available.

+ Details

Name:	ccne_ExpensesRelatedToSupplementalExecutiveRetirementPlan
Namespace Prefix:	ccne_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Expenses related to survivor benefit plan.

+ References

No definition available.

+ Details

Name:	ccne_ExpensesRelatedToSurvivorBenefitPlan
Namespace Prefix:	ccne_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Minimum age for participation in benefit plan.

+ References

No definition available.

+ Details

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

- Definition

Minimum service period for participation in benefit plan.

+ References

No definition available.

+ Details

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

- Definition

Obligations under survivor benefit plan.

+ References

No definition available.

+ Details

Name:	ccne_ObligationsUnderSurvivorBenefitPlan
Namespace Prefix:	ccne_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Percent rate of decrease in the health care trend.

+ References

No definition available.

+ Details

Name:	ccne_PercentRateOfDecreaseInHealthCareTrend
Namespace Prefix:	ccne_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percent rate of increase in the health care trend.

+ References

No definition available.

+ Details

Name:	ccne_PercentRateOfIncreaseInHealthCareTrend
Namespace Prefix:	ccne_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Profit sharing contributions.

+ References

No definition available.

+ Details

Name:	ccne_ProfitSharingContributions
Namespace Prefix:	ccne_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Qualifying dependents age group.

+ References

No definition available.

+ Details

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

- Definition

Recognized profit sharing expense.

+ References

No definition available.

+ Details

Name:	ccne_RecognizedProfitSharingExpense
Namespace Prefix:	ccne_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Weighted average rate accrued benefit obligations.

+ References

No definition available.

+ Details

Name:	ccne_WeightedAverageRateAccruedBenefitObligations
Namespace Prefix:	ccne_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

For defined benefit pension plans, the actuarial present value of benefits (whether vested or nonvested) attributed by the pension benefit formula to employee service rendered before a specified date and based on employee service and compensation (if applicable) before that date. The accumulated benefit obligation differs from the projected benefit obligation in that it includes no assumption about future compensation levels. For plans with flat-benefit or nonpay-related pension benefit formulas, the accumulated benefit obligation and the projected benefit obligation are the same.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Accumulated Benefit Obligation
-URI http://asc.fasb.org/extlink&oid=6503844

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920

+ Details

Name:	us-gaap_DefinedBenefitPlanAccumulatedBenefitObligation
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The interest rate used to adjust for the time value of money.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (k)(1)
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920

+ Details

Name:	us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of effect of a one-percentage-point decrease in the assumed health care cost trend rates on the accumulated postretirement benefit obligation for health care benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (m)
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920

+ Details

Name:	us-gaap_DefinedBenefitPlanEffectOfOnePercentagePointDecreaseOnAccumulatedPostretirementBenefitObligation1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of effect of a one-percentage-point decrease in the assumed health care cost trend rates on the aggregate of the service and interest cost components of net periodic postretirement health care benefit costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (m)
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920

+ Details

Name:	us-gaap_DefinedBenefitPlanEffectOfOnePercentagePointDecreaseOnServiceAndInterestCostComponents1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The effect of a one-percentage-point increase in the assumed health care cost trend rates on the accumulated postretirement benefit obligation for health care benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (m)
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920

+ Details

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

- Definition

The effect of a one-percentage-point increase in the assumed health care cost trend rates on the aggregate of the service and interest cost components of net periodic postretirement health care benefit costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (m)
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920

+ Details

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

- Definition

The assumed health care cost trend rate for the next year used to measure the expected cost of benefits covered by the plan (gross eligible charges). This is based upon the annual rate of change in the cost of health care benefits currently provided by the postretirement benefit plan, due to factors other than changes in the composition of the plan population by age and dependency status.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Health Care Cost Trend Rate
-URI http://asc.fasb.org/extlink&oid=6514820

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (l)
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920

+ Details

Name:	us-gaap_DefinedBenefitPlanHealthCareCostTrendRateAssumedForNextFiscalYear
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of discretionary contributions made by an employer to a defined contribution plan.

+ References

No definition available.

+ Details

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

- Definition

Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan.

+ References

No definition available.

+ Details

Name:	us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum percentage of employee gross pay the employee may contribute to a defined contribution plan.

+ References

No definition available.

+ Details

Name:	us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

This represents the entire liability recognized in the balance sheet that is associated with the defined benefit plans.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=21915240&loc=d3e1703-114919

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.15)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e2417-114920

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.15)
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e2410-114920

+ Details

Name:	us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesCurrentAndNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

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

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: