LOAN CREDIT QUALITY AND RELATED ALLOWANCE FOR LOAN LOSSES - Additional Information (Details)	12 Months Ended
	Dec. 31, 2017 USD ($) category class loan component	Dec. 31, 2016 USD ($) loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Minimum amount to evaluate individual loans for possible impairment	$ 100,000
Maximum amount to evaluate individual loans for possible impairment on a case by case basis	$ 100,000
Payment delays period up to which loans are not classified as impaired, maximum (in days)	90 days
Period to classify TDR non performing loans to performing (in months)	6 months
Number of TDRs granted | loan	8	4
Amount of TDRs granted		$ 797,000
Number of categories considered not criticized and rated as Pass | category	6
Minimum period after which loans are considered as substandard (in days)	90 days
Number of components that represents the allowance for loan losses | component	2
Number of classes that groups of loans are collectively evaluated for impairment | class	2
Period considered for quarter moving average which used in calculating historical charge off (in months)	36 months
Adjustment of period considered for quarter moving average which used in calculating historical charge off (in months)	12 months
Increase of basis points	20.00%
Amount of foreclosed residential real estate held	$ 422,000	839,000
Consumer mortgage loans secured by residential real estate properties for which formal foreclosure proceedings are in process	378,000	$ 167,000
Luzerne National Bank Corporation
Accounts, Notes, Loans and Financing Receivable [Line Items]
Minimum amount after which external annual loan review is performed	1,400,000
Jersey Shore State Bank
Accounts, Notes, Loans and Financing Receivable [Line Items]
Minimum amount after which external annual loan review is performed	$ 1,600,000
Payment Concession
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDRs granted | loan	6
Amount of TDRs granted	$ 1,061,000
Rate Concession
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDRs granted | loan	1
Amount of TDRs granted	$ 273,000
Term Concession
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDRs granted | loan	1
Amount of TDRs granted	$ 52,000
Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of categories in which real estate loans are segmented | category	3