BORROWED FUNDS - Short-term borrowings - Additional information (Details) - USD ($)	Jun. 30, 2024	Dec. 31, 2023
BORROWED FUNDS
Short-term borrowings	$ 16,874,000	$ 33,874,000
Other Assets [Member]
BORROWED FUNDS
Federal Home Loan Bank Stock	6,276,000	6,252,000
Other Correspondent Banks
BORROWED FUNDS
Line of Credit Facility, Maximum Borrowing Capacity	75,000,000	75,000,000
Long-term Line of Credit, Total	0	0
Federal Reserve Bank of Philadelphia \| Collateral Pledged
BORROWED FUNDS
Investment pledged as collateral	$ 19,718,000	$ 20,829,000
Customer repurchase agreements
BORROWED FUNDS
Debt, Weighted Average Interest Rate	0.10%	0.10%
Carrying Value of Securities Sold under Repurchase Agreements and Deposits Received for Securities Loaned, Total	$ 1,880,000	$ 2,400,000
Short-term borrowings	1,874,000	2,374,000
FHLB-Pittsburgh borrowings
BORROWED FUNDS
Short-term borrowings	15,000,000	31,500,000
Federal Home Loan Bank of Pittsburgh
BORROWED FUNDS
Line of Credit Facility, Maximum Borrowing Capacity	943,575,000	926,845,000
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged	1,347,570,000	1,323,008,000
Line of Credit Facility, Remaining Borrowing Capacity	719,722,000	737,824,000
Federal Home Loan Bank of Pittsburgh \| Other Assets [Member]
BORROWED FUNDS
Federal Home Loan Bank Stock	16,464,000	15,214,000
Federal Home Loan Bank of Pittsburgh \| Federal Reserve Bank of Philadelphia
BORROWED FUNDS
Line of Credit Facility, Maximum Borrowing Capacity	18,884,000	19,982,000
Long-term Line of Credit, Total	$ 0	$ 0
Federal Home Loan Bank of Pittsburgh \| Overnight Borrowing
BORROWED FUNDS
Federal Home Loan Bank, Advances, Branch of FHLB Bank, Interest Rate		5.68%
Short-term borrowings		$ 6,500,000
Federal Home Loan Bank of Pittsburgh \| Federal Home Loan Bank Advances 1
BORROWED FUNDS
Federal Home Loan Bank, Advances, Branch of FHLB Bank, Interest Rate	5.32%	5.60%
Short-term borrowings	$ 15,000,000	$ 25,000,000

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

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