XML 34 R30.htm IDEA: XBRL DOCUMENT v2.4.1.9
Fair Value - Quantitative Information About Level 3 Fair Value Measurements (Detail) (Pooled Trust Preferred [Member], USD $)
In Thousands, unless otherwise specified
 3 Months Ended 12 Months Ended
Mar. 31, 2015
Dec. 31, 2014
Fair Value Inputs, Assets, Quantitative Information [Line Items]    
Fair value 905us-gaap_AssetsFairValueDisclosure 905us-gaap_AssetsFairValueDisclosure
Collateral Default Rate [Member] | Discounted Cash Flow [Member]
    
Fair Value Inputs, Assets, Quantitative Information [Line Items]    
Input utilized two 0.83% in 2015; 0.5% in 2016 and thereafter 1% in 2015; 0.5% in 2016 and thereafter
Yield [Member] | Discounted Cash Flow [Member]
    
Fair Value Inputs, Assets, Quantitative Information [Line Items]    
Input utilized one 13.00%ccne_InputUtilizedOne
/ us-gaap_FairValueByAssetClassAxis
= ccne_PooledTrustPreferredMember
/ us-gaap_FairValueConcentrationOfRiskDisclosureItemsAxis
= ccne_YieldMember
/ us-gaap_ValuationTechniqueAxis
= ccne_DiscountedCashFlowMember		 11.00%ccne_InputUtilizedOne
/ us-gaap_FairValueByAssetClassAxis
= ccne_PooledTrustPreferredMember
/ us-gaap_FairValueConcentrationOfRiskDisclosureItemsAxis
= ccne_YieldMember
/ us-gaap_ValuationTechniqueAxis
= ccne_DiscountedCashFlowMember
Prepayment Speed [Member] | Discounted Cash Flow [Member]
    
Fair Value Inputs, Assets, Quantitative Information [Line Items]    
Input utilized two 2.0% constant prepayment rate in 2015 and thereafter 2.0% constant prepayment rate in 2015 and thereafter