BORROWED FUNDS AND SUBORDINATED DEBT - Additional Information (Details)	Sep. 30, 2020 USD ($) loanfacility	Dec. 31, 2019 USD ($)
BORROWED FUNDS AND SUBORDINATED DEBT
Letter of credit	$ 400,000
Subordinated Debt, Ending Balance	16,572,000	$ 6,500,000
Other Correspondent Banks
BORROWED FUNDS AND SUBORDINATED DEBT
Line of Credit Facility, Maximum Borrowing Capacity	45,000,000	45,000,000
Long-term Line of Credit, Total	0	0
Federal Reserve Bank of Philadelphia \| Collateral Pledged
BORROWED FUNDS AND SUBORDINATED DEBT
Debt Securities, Available-for-sale, Restricted	$ 15,124,000	$ 14,728,000
Customer repurchase agreements
BORROWED FUNDS AND SUBORDINATED DEBT
Debt, Weighted Average Interest Rate	0.10%	0.10%
Carrying Value of Securities Sold under Repurchase Agreements and Deposits Received for Securities Loaned, Total	$ 2,350,000	$ 1,951,000
Federal Home Loan Bank of Pittsburgh
BORROWED FUNDS AND SUBORDINATED DEBT
Line of Credit Facility, Maximum Borrowing Capacity	782,434,000	552,546,000
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged	1,062,779,000	778,877,000
Line of Credit Facility, Remaining Borrowing Capacity	641,753,000	416,122,000
Federal Home Loan Bank of Pittsburgh \| Other Assets
BORROWED FUNDS AND SUBORDINATED DEBT
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged	11,929,000	10,131,000
Federal Home Loan Bank Stock	11,929,000	10,131,000
Federal Home Loan Bank of Pittsburgh \| Federal Reserve Bank of Philadelphia
BORROWED FUNDS AND SUBORDINATED DEBT
Line of Credit Facility, Maximum Borrowing Capacity	14,654,000	14,244,000
Long-term Line of Credit, Total	$ 0	$ 0
Federal Home Loan Bank of Pittsburgh \| Federal Home Loan Bank Advances 1
BORROWED FUNDS AND SUBORDINATED DEBT
Number of Short-term Advances \| loanfacility	10
Short-term Borrowing, Amount of Each Borrowing	$ 38,400,000
Short-term Debt, Weighted Average Interest Rate, at Point in Time	0.58%

The number of short-term advances as of the balance sheet date.

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Reflects the amount of each short-term borrowing.

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Carrying value of securities sold under agreements to repurchase and deposits received for securities loaned.

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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.

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Amount of restricted investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Weighted average interest rate of debt outstanding.

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Amount of the collateral pledged in support of federal home loan bank advances outstanding.

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Federal Home Loan Bank (FHLB) stock represents an equity interest in a FHLB. It does not have a readily determinable fair value because its ownership is restricted and it lacks a market (liquidity).

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The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

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No definition available.

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The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

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Weighted average interest rate of short-term debt outstanding calculated at point in time.

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Including the current and noncurrent portions, carrying value as of the balance sheet date of subordinated debt (with initial maturities beyond one year or beyond the operating cycle if longer). Subordinated debt places a lender in a lien position behind debt having a higher priority of repayment in liquidation of the entity's assets.

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