Parent Company Only Financial Information - Condensed Statements of Cash Flows (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended	1 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Condensed Financial Statements, Captions [Line Items]
Net income	$ 23,074us-gaap_NetIncomeLoss	$ 16,679us-gaap_NetIncomeLoss	$ 17,136us-gaap_NetIncomeLoss
Adjustments to reconcile net income to net cash provided by operating activities:
Net unrealized (gains) losses on trading securities	(121)	(728)	(564)
Decrease (increase) in other assets	6,266	(3,124)	(455)
Increase in other liabilities	(6,605)	8,387	2,523
Net Cash Provided By Operating Activities	28,920	33,609	27,560
Cash flows from investing activities	(55,526)	(36,452)	(182,620)
Cash Flows From Financing Activities:
Dividends paid	(9,521)us-gaap_PaymentsOfDividends	(8,573)us-gaap_PaymentsOfDividends	(8,214)us-gaap_PaymentsOfDividends
Purchase of treasury stock	(1,675)ccne_PaymentsForPurchaseOfTreasuryStock	0ccne_PaymentsForPurchaseOfTreasuryStock	0ccne_PaymentsForPurchaseOfTreasuryStock
Net Cash Provided By Financing Activities	24,901	595	147,238
Net increase (decrease) in cash	(1,705)	(2,248)	(7,822)
Cash and Cash Equivalents, Beginning	29,633	31,881	39,703
Cash and Cash Equivalents, Ending	27,928	29,633	31,881	27,928	29,633	31,881
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Net income	23,074	16,679	17,136	23,074	16,679	17,136
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in undistributed net income of bank subsidiary	(12,327)	(14,080)	(8,682)	(12,327)	(14,080)	(8,682)
Equity in undistributed (net income) loss of non-bank subsidiaries	(949)	5,135	(1,275)	(949)	5,135	(1,275)
Net unrealized (gains) losses on trading securities				1	(47)	(54)
Decrease (increase) in other assets				(13)	112	47
Increase in other liabilities				601	384	385
Net Cash Provided By Operating Activities				10,387	8,183	7,557
Cash flows from investing activities				0	0	0
Cash Flows From Financing Activities:
Dividends paid				(9,521)	(8,573)	(8,214)
Purchase of treasury stock				(1,675)	0	0
Net proceeds from sale of treasury stock and option exercises				587	739	950
Net advance to subsidiary				0	(600)	(200)
Net Cash Provided By Financing Activities				(10,609)	(8,434)	(7,464)
Net increase (decrease) in cash				(222)	(251)	93
Cash and Cash Equivalents, Beginning	1,778	2,029		1,778	2,029	1,936
Cash and Cash Equivalents, Ending	$ 1,556	$ 1,778	$ 2,029	$ 1,556	$ 1,778	$ 2,029

Equity in undistributed net income (loss) of non bank subsidiaries.

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Equity in undistributed net income of bank subsidiary.

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Net advance from subsidiary.

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Payments For Purchase Of Treasury Stock

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Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

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