ACNB (ACNB) 10-K 6 Mar 20 2019 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2019	Mar. 06, 2020	Jun. 30, 2019
Document and Entity Information [Abstract]
Document Type	10-K
Document Period End Date	Dec. 31, 2019
Entity Registrant Name	ACNB CORP
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 267,627,698
Entity Common Stock, Shares Outstanding		7,079,359
Entity Central Index Key	0000715579
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Entity Interactive Data Current	Yes
Amendment Flag	false

CONSOLIDATED STATEMENTS OF COND

CONSOLIDATED STATEMENTS OF CONDITION - USD ($)	Dec. 31, 2019	Dec. 31, 2018
ASSETS
Cash and due from banks	$ 16,878,000	$ 20,105,000
Interest bearing deposits with banks	97,478,000	20,800,000
Total Cash and Cash Equivalents	114,356,000	40,905,000
Equity securities with readily determinable fair values	2,106,000	1,839,000
Debt securities available for sale	190,837,000	161,730,000
Securities held to maturity, fair value $19,281; $26,911	19,234,000	27,266,000
Loans held for sale	2,406,000	408,000
Loans, net of allowance for loan losses $13,835; $13,964	1,258,766,000	1,288,501,000
Premises and equipment	25,724,000	26,409,000
Right of use assets	3,502,000	0
Restricted investment in bank stocks	3,644,000	4,336,000
Investment in bank-owned life insurance	50,663,000	48,003,000
Investments in low-income housing partnerships	1,506,000	1,871,000
Goodwill	19,580,000	19,580,000
Intangible assets	4,427,000	4,407,000
Foreclosed assets held for resale	364,000	155,000
Other assets	23,138,000	22,314,000
Total Assets	1,720,253,000	1,647,724,000
LIABILITIES
Deposits: Non-interest bearing	314,377,000	302,394,000
Deposits: Interest bearing	1,097,883,000	1,045,698,000
Total Deposits	1,412,260,000	1,348,092,000
Short-term borrowings	33,435,000	34,648,000
Long-term borrowings	66,296,000	83,516,000
Lease liabilities	3,502,000	0
Other liabilities	15,244,000	13,331,000
Total Liabilities	1,530,737,000	1,479,587,000
STOCKHOLDERS' EQUITY
Preferred stock, $2.50 par value; 20,000,000 shares authorized; no shares outstanding	0	0
Common stock, $2.50 par value; 20,000,000 shares authorized; 7,141,959 and 7,108,620 shares issued; 7,079,359 and 7,046,020 shares outstanding	17,855,000	17,772,000
Treasury stock, at cost (62,600 shares)	(728,000)	(728,000)
Additional paid-in capital	39,579,000	38,448,000
Retained earnings	138,663,000	121,862,000
Accumulated other comprehensive loss	(5,853,000)	(9,217,000)
Total Stockholders’ Equity	189,516,000	168,137,000
Total Liabilities and Stockholders’ Equity	$ 1,720,253,000	$ 1,647,724,000

CONSOLIDATED STATEMENTS OF CO_2

CONSOLIDATED STATEMENTS OF CONDITION (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Securities held to maturity, fair value	$ 19,281	$ 26,911
Loans, net allowance for loan losses	$ 13,835	$ 13,964
Preferred stock, par value	$ 2.50	$ 2.50
Preferred stock, shares authorized	20,000,000	20,000,000
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 2.50	$ 2.50
Common stock, shares authorized	20,000,000	20,000,000
Common stock, shares issued	7,141,959	7,108,620
Common stock, shares outstanding	7,079,359	7,046,020
Treasury stock, shares	62,600	62,600

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
INTEREST AND DIVIDEND INCOME
Loans, including fees	$ 63,653,000	$ 59,593,000
Securities:
Taxable	4,183,000	3,735,000
Tax-exempt	140,000	219,000
Dividends	328,000	299,000
Other	1,254,000	648,000
Total Interest Income	69,558,000	64,494,000
INTEREST EXPENSE
Deposits	8,129,000	5,253,000
Short-term borrowings	94,000	59,000
Long-term borrowings	1,917,000	2,087,000
Total Interest Expense	10,140,000	7,399,000
Net Interest Income	59,418,000	57,095,000
PROVISION FOR LOAN LOSSES	600,000	1,620,000
Net Interest Income after Provision for Loan Losses	58,818,000	55,475,000
OTHER INCOME
Commissions from insurance sales	6,339,000	5,550,000
Earnings on investment in bank-owned life insurance	1,160,000	1,068,000
Gain on life insurance proceeds	0	52,000
Net gains on sales or calls of securities	0	85,000
Net gains (losses) on equity securities	267,000	(296,000)
Other	1,587,000	1,400,000
Total Other Income	18,169,000	15,948,000
OTHER EXPENSES
Salaries and employee benefits	28,798,000	26,734,000
Net occupancy	3,094,000	2,971,000
Equipment	4,771,000	4,959,000
Other tax	1,086,000	902,000
Professional services	1,772,000	1,468,000
Supplies and postage	747,000	766,000
Marketing and corporate relations	559,000	565,000
FDIC and regulatory	436,000	688,000
Merger related expenses	769,000	0
Intangible assets amortization	621,000	745,000
Foreclosed real estate expenses	12,000	129,000
Other operating	4,956,000	4,776,000
Total Other Expenses	47,621,000	44,703,000
Income Before Income Taxes	29,366,000	26,720,000
PROVISION FOR INCOME TAXES	5,645,000	4,972,000
Net Income	$ 23,721,000	$ 21,748,000
PER SHARE DATA
Basic earnings	$ 3.36	$ 3.09
Cash dividends declared	$ 0.98	$ 0.89
Service charges on deposit accounts
OTHER INCOME
Revenue from Contract with Customer, Excluding Assessed Tax	$ 3,903,000	$ 3,350,000
Income from fiduciary, investment management and brokerage activities
OTHER INCOME
Revenue from Contract with Customer, Excluding Assessed Tax	2,469,000	2,364,000
Service charges on ATM and debit card transactions
OTHER INCOME
Revenue from Contract with Customer, Excluding Assessed Tax	$ 2,444,000	$ 2,375,000

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
NET INCOME		$ 23,721	$ 21,748
OTHER COMPREHENSIVE INCOME (LOSS)
SECURITIES: Unrealized gains (losses) arising during the period, net of income taxes of $849 and $(153), respectively		2,912	(537)
SECURITIES: Reclassification adjustment for net gains included in net income, net of income taxes, $0 and $(46), respectively	[1],[2]	0	(157)
PENSION: Amortization of pension net loss, transition liability, and prior service cost, net of income taxes of $155 and $116, respectively	[2],[3]	657	400
PENSION: Unrecognized net loss, net of income taxes of $(19) and $(534), respectively	[2]	(205)	(1,831)
TOTAL OTHER COMPREHENSIVE INCOME (LOSS)		3,364	(2,125)
TOTAL COMPREHENSIVE INCOME		$ 27,085	$ 19,623
[1]	Gross amounts are included in net gains on sales or calls of securities on the Consolidated Statements of Income in total other income.
[2]	Income tax amounts are included in the provision for income taxes on the Consolidated Statements of Income.
[3]	Gross amounts are included in the computation of net periodic benefit cost and are included in salaries and employee benefits on the Consolidated Statements of Income in total other expenses.

CONSOLIDATED STATEMENTS OF CO_3

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
SECURITIES: Unrealized gains (losses) arising during the period, income taxes	$ 849	$ (153)
SECURITIES: Reclassification adjustment for net gains included in net income, income taxes	0	(46)
PENSION: Amortization of pension net loss, transition liability, and prior service cost, income taxes	155	116
PENSION: Unrecognized net loss, income taxes	$ (19)	$ (534)

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($)	Total	Common Stock	Treasury Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Beginning Balance at Dec. 31, 2017	$ 153,966,000	$ 17,716,000	$ (728,000)	$ 37,777,000	$ 106,293,000	$ (7,092,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	21,748,000				21,748,000
Other comprehensive loss, net of taxes	(2,043,000)					(2,043,000)
Other comprehensive income (loss), net of taxes	(2,125,000)
Reclass of stranded AOCI tax reform adjustment	0				82,000	(82,000)
Common stock shares issued	528,000	39,000		489,000
Restricted stock grants	13,000	17,000		(4,000)
Restricted stock compensation expense	186,000			186,000
Cash dividends declared	(6,261,000)				(6,261,000)
Ending Balance at Dec. 31, 2018	168,137,000	17,772,000	(728,000)	38,448,000	121,862,000	(9,217,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	23,721,000				23,721,000
Other comprehensive income (loss), net of taxes	3,364,000					3,364,000
Common stock shares issued	501,000	44,000		457,000
Restricted stock grants	391,000	39,000		352,000
Restricted stock compensation expense	322,000			322,000
Cash dividends declared	(6,920,000)				(6,920,000)
Ending Balance at Dec. 31, 2019	$ 189,516,000	$ 17,855,000	$ (728,000)	$ 39,579,000	$ 138,663,000	$ (5,853,000)

CONSOLIDATED STATEMENTS OF CH_2

CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (Parenthetical) - shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Statement of Stockholders' Equity [Abstract]
Common stock issued, shares	17,324	15,618
Restricted stock grants, shares	16,115	6,644

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 23,721,000	$ 21,748,000
Adjustments to reconcile net income to net cash provided by operating activities:
Gain on sales of loans originated for sale	(697,000)	(542,000)
(Gain) loss on sales of foreclosed assets held for resale, including writedowns	(87,000)	1,000
Earnings on investment in bank-owned life insurance	(1,160,000)	(1,068,000)
Gain on sales or calls of securities	0	(85,000)
(Gain) loss on equity securities	(267,000)	296,000
Restricted stock compensation expense	322,000	186,000
Depreciation and amortization	2,696,000	2,853,000
Provision for loan losses	600,000	1,620,000
Net amortization of investment securities premiums	339,000	465,000
Decrease (increase) in accrued interest receivable	177,000	(875,000)
Increase in accrued interest payable	1,312,000	201,000
Mortgage loans originated for sale	(41,389,000)	(32,436,000)
Proceeds from sales of loans originated for sale	40,088,000	34,306,000
(Increase) decrease in other assets	(1,280,000)	2,502,000
Decrease in deferred tax expense	120,000	557,000
Increase (decrease) in other liabilities	1,228,000	(185,000)
Net Cash Provided by Operating Activities	25,723,000	29,544,000
CASH FLOWS FROM INVESTING ACTIVITIES
Proceeds from maturities of investment securities held to maturity	8,032,000	17,558,000
Proceeds from maturities of investment securities available for sale	19,152,000	17,925,000
Proceeds from sales of investment securities available for sale	0	15,566,000
Purchase of investment securities available for sale	(44,837,000)	(39,129,000)
Purchase of equity securities	(500,000)	0
Redemption of restricted investment in bank stocks	692,000	437,000
Net decrease (increase) in loans	28,723,000	(60,254,000)
Purchase of bank-owned life insurance	(1,500,000)	(2,000,000)
Insurance book- acquisition	(640,000)	(2,583,000)
Capital expenditures	(1,424,000)	(1,743,000)
Proceeds from sale of premises and equipment	33,000	0
Proceeds from sale of foreclosed real estate	290,000	607,000
Net Cash Provided by (Used in) Investing Activities	8,021,000	(53,616,000)
CASH FLOWS FROM FINANCING ACTIVITIES
Net increase in demand deposits	11,983,000	22,981,000
Net increase in time certificates of deposits and interest bearing deposits	52,185,000	26,619,000
Net decrease in short-term borrowings	(1,213,000)	(2,260,000)
Proceeds from long-term borrowings	7,000,000	17,716,000
Repayments on long-term borrowings	(24,220,000)	(28,800,000)
Dividends paid	(6,920,000)	(6,261,000)
Common stock issued	892,000	541,000
Net Cash Provided by (Used in) Financing Activities	39,707,000	30,536,000
Net Increase (Decrease) in Cash and Cash Equivalents	73,451,000	6,464,000
CASH AND CASH EQUIVALENTS — BEGINNING	40,905,000	34,441,000
CASH AND CASH EQUIVALENTS — ENDING	114,356,000	40,905,000
Supplemental disclosures of cash flow information
Interest paid	8,828,000	7,198,000
Income taxes paid	5,200,000	4,600,000
Loans transferred to foreclosed assets held for resale and other foreclosed transactions	$ 412,000	$ 327,000

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Nature of Operations ACNB Corporation (the Corporation or ACNB), headquartered in Gettysburg, Pennsylvania, provides banking, insurance, and financial services to businesses and consumers through its wholly-owned subsidiaries, ACNB Bank (Bank) and Russell Insurance Group, Inc. (RIG). The Bank engages in full-service commercial and consumer banking and wealth management services, including trust and retail brokerage, through its twenty-two community banking office locations in Adams, Cumberland, Franklin, and York Counties, Pennsylvania. There are also loan production offices situated in Lancaster and York, Pennsylvania, and Hunt Valley, Maryland. RIG is a full-service insurance agency based in Westminster, Maryland, with additional locations in Germantown and Jarrettsville, Maryland. The agency offers a broad range of property and casualty and group life and health insurance to both individual and commercial clients. On July 1, 2017, ACNB completed its acquisition of New Windsor Bancorp, Inc. (New Windsor) of Taneytown, Maryland. At the effective time of the acquisition, New Windsor merged with and into a wholly-owned subsidiary of ACNB, immediately followed by the merger of New Windsor State Bank (NWSB) with and into ACNB Bank. ACNB Bank now operates in the Maryland market as “NWSB Bank, A Division of ACNB Bank” and serves its marketplace with banking and wealth management services via a network of seven community banking offices located in Carroll County, Maryland. Effective January 11, 2020, ACNB completed its acquisition of Frederick County Bancorp, Inc. (FCBI) and its wholly-owned subsidiary, Frederick County Bank, headquartered in Frederick, Maryland. FCBI was merged with and into a wholly-owned subsidiary of ACNB Corporation immediately followed by the merger of Frederick County Bank with and into ACNB Bank. ACNB Bank will operate in the Frederick County, Maryland, market as “FCB Bank, A Division of ACNB Bank”. Under the terms of the Reorganization Agreement, FCBI stockholders received 0.9900 share of ACNB Corporation common stock for each share of FCBI common stock that they owned as of the closing date. As a result, ACNB Corporation issued 1,590,547 shares of its common stock and cash in exchange for fractional shares based upon $36.43 , the determined market share price of ACNB Corporation common stock in accordance with the Reorganization Agreement. One director from FCBI will join the boards of directors of ACNB and ACNB Bank, respectively. With the combination of the two organizations, ACNB Corporation, on a consolidated basis, has approximately $2.2 billion in assets, $1.8 billion in deposits, and $1.6 billion in loans with 34 community banking offices and three loan offices located in the counties of Adams, Cumberland, Franklin, Lancaster and York in Pennsylvania, and the counties of Baltimore, Carroll and Frederick in Maryland. Further discussion of the risk factors involved with the merger of FCBI into the Corporation can be found in Part I, Item 1A–Risk Factors. The Corporation’s primary sources of revenue are interest income on loans and investment securities and fee income on its products and services. Expenses consist of interest expense on deposits and borrowed funds, provisions for loan losses, and other operating expenses. Basis of Financial Statements The consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (US GAAP) and include the accounts of the Corporation and its wholly-owned subsidiaries. All significant intercompany transactions have been eliminated. Assets held by the Corporation’s Wealth Management Department, including trust and retail brokerage, in an agency, fiduciary or retail brokerage capacity for its customers are excluded from the consolidated financial statements since they do not constitute assets of the Corporation. Assets held by the Wealth Management Department amounted to $389,000,000 and $342,000,000 at December 31, 2019 and 2018 , respectively. Income from fiduciary, investment management and brokerage activities are included in other income. The Corporation has evaluated events and transactions occurring subsequent to the balance sheet date of December 31, 2019 , for items that should potentially be recognized or disclosed in the consolidated financial statements. The evaluation was conducted through the date these consolidated financial statements were issued. Use of Estimates Financial statements prepared in accordance with GAAP require management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingencies at the date of the consolidated financial statements, and revenues and expenses during the reporting period. Actual results could differ from these estimates. Material estimates that are particularly susceptible to significant change in the near term relate to the determination of the allowance for loan losses, the determination of other than temporary impairment on securities, and the potential impairment of goodwill. Significant Group Concentrations of Credit Risk Most of the Corporation’s activities are with customers located within southcentral Pennsylvania and northern Maryland. Note C discusses the types of securities in which the Corporation invests. Note D discusses the types of lending in which the Corporation engages. Included in commercial real estate loans are loans made to lessors of non-residential dwellings that total $297,654,000 , or 23.4% , of total loans at December 31, 2019 . These borrowers are geographically disbursed throughout ACNB’s marketplace and are leasing commercial properties to a varied group of tenants including medical offices, retail space and recreational facilities. Because of the varied nature of the tenants in aggregate, management believes that these loans do not present any greater risk than commercial loans in general. Cash and Cash Equivalents For purposes of the consolidated statements of cash flows, cash and cash equivalents include cash on hand, balances due from banks, and federal funds sold, all of which mature within 90 days. Securities Debt securities that management has the positive intent and ability to hold to maturity are classified as “held to maturity” and recorded at amortized cost. Debt securities not classified as held to maturity or trading are classified as “available for sale” and recorded at fair value, with unrealized gains and losses excluded from earnings and reported, net of tax, in other comprehensive income (loss). As of January 1, 2018, equity securities with readily determined fair values are recorded at fair value with changes in fair value recognized in net income. Prior to 2018, fair value changes were reported, net of tax, in other comprehensive income (loss). Purchase premiums and discounts are recognized in interest income using the interest method over the terms of the securities. Declines in the fair value of held to maturity and available for sale securities below their cost that are deemed to be other than temporary are reflected in earnings as realized losses. In estimating other-than-temporary impairment losses on debt securities, management considers (1) whether management intends to sell the security, or (2) if it is more likely than not that management will be required to sell the security before recovery, or (3) if management does not expect to recover the entire amortized cost basis. In assessing potential other-than-temporary impairment for equity securities, consideration is given to management’s intention and ability to hold the securities until recovery of unrealized losses. Gains and losses on the sale of securities are recorded on the trade date and are determined using the specific identification method. Loans Held for Sale Loans originated and intended for sale in the secondary market are carried at the lower of aggregate cost or fair value, as determined by aggregate outstanding commitments from investors or current investor yield requirements. Net unrealized losses are recognized through a valuation allowance by charges to income. Mortgage loans held for sale are sold with the mortgage servicing rights released to another financial institution through a correspondent relationship. The correspondent financial institution absorbs all of the risk related to rate lock commitments. Gains or losses on sales of mortgage loans are recognized based on the difference between the selling price and the carrying value of the related mortgage loans sold. Loans The Corporation grants commercial, residential, and consumer loans to customers. A substantial portion of the loan portfolio is represented by mortgage loans throughout southcentral Pennsylvania and northern Maryland. The ability of the Corporation’s debtors to honor their contracts is dependent upon the real estate values and general economic conditions in this area. Loans that management has the intent and ability to hold for the foreseeable future or until maturity or pay-off generally are reported at their outstanding unpaid principal balances adjusted for charge-offs, the allowance for loan losses, and any deferred fees or costs on originated loans. Interest income is accrued on the unpaid principal balance. Loan origination fees, net of certain direct origination costs, are deferred and recognized as an adjustment of the related loan yield using the interest method. The loans receivable portfolio is segmented into commercial, residential mortgage, home equity lines of credit, and consumer loans. Commercial loans consist of the following classes: commercial and industrial, commercial real estate, and commercial real estate construction. The accrual of interest on residential mortgage and commercial loans is discontinued at the time the loan is 90 days past due unless the credit is well-secured and in process of collection. Consumer loans (consisting of home equity lines of credit and consumer loan classes) are typically charged off no later than 120 days past due. Past due status is based on the contractual terms of the loan. In all cases, loans are placed on nonaccrual or charged off at an earlier date if collection of principal or interest is considered doubtful. All interest accrued, but not collected, for loans that are placed on nonaccrual or charged off is reversed against interest income. The interest on these loans is accounted for on the cash-basis or cost-recovery method, until qualifying for return to accrual status. Loans are returned to accrual status when all the principal and interest amounts contractually due are brought current and future payments are reasonably assured. Allowance for Credit Losses The allowance for credit losses consists of the allowance for loan losses and the reserve for unfunded lending commitments. The allowance for loan losses (the “allowance”) is established as losses are estimated to occur through a provision for loan losses charged to earnings. Loan losses are charged against the allowance when management believes the uncollectibility of a loan balance is confirmed. Subsequent recoveries, if any, are credited to the allowance. The reserve for unfunded lending commitments represents management’s estimate of losses inherent in its unfunded loan commitments and is recorded in other liabilities on the consolidated statement of condition. The amount of the reserve for unfunded lending commitments is not material to the consolidated financial statements. The allowance for loan losses is evaluated on a regular basis by management and is based upon management’s periodic review of the collectibility of the loans in light of historical experience, the nature and volume of the loan portfolio, adverse situations that may affect the borrower’s ability to repay, estimated value of any underlying collateral, and prevailing economic conditions. This evaluation is inherently subjective as it requires estimates that are susceptible to significant revision as more information becomes available. The allowance consists of specific, general and unallocated components. The specific component relates to loans that are classified as either doubtful, substandard, or special mention. For such loans that are also classified as impaired, an allowance is established when the discounted cash flows (or collateral value or observable market price) of the impaired loan is lower than the carrying value of that loan. The general component covers pools of loans by loan class including commercial loans not considered impaired, as well as smaller balance homogeneous loans, such as residential real estate, home equity, and other consumer loans. These pools of loans are evaluated for loss exposure based upon historical loss rates for each of these categories of loans, adjusted for qualitative risk factors. These qualitative risk factors include: • lending policies and procedures, including underwriting standards and collection, charge-off and recovery practices; • national, regional and local economic and business conditions, as well as the condition of various market segments, including the impact on the value of underlying collateral for collateral dependent loans; • the nature and volume of the portfolio and terms of loans; • the experience, ability and depth of lending management and staff; • the volume and severity of past due, classified and nonaccrual loans, as well as other loan modifications; and, • the existence and effect of any concentrations of credit and changes in the level of such concentrations. Each factor is assigned a value to reflect improving, stable or declining conditions based on management’s best judgment using relevant information available at the time of the evaluation. Adjustments to the factors are supported through documentation of changes in conditions in a narrative accompanying the allowance for loan loss calculation. The unallocated component of the allowance is maintained to cover uncertainties that could affect management’s estimate of probable losses. The unallocated component of the allowance reflects the margin of imprecision inherent in the underlying assumptions used in the methodologies for estimating specific and general losses in the portfolio. It covers risks that are inherently difficult to quantify including, but not limited to, collateral risk, information risk, and historical charge-off risk. A loan is considered impaired when, based on current information and events, it is probable that the Corporation will be unable to collect the scheduled payments of principal and/or interest when due according to the contractual terms of the loan agreement. Factors considered by management in determining impairment include payment status, collateral value, and the probability of collecting scheduled principal and/or interest payments when due. Loans that experience insignificant payment delays and payment shortfalls generally are not classified as impaired. Management determines the significance of payment delays and payment shortfalls on a case-by-case basis, taking into consideration all of the circumstances surrounding the loan and the borrower, including the length of the delay, the reasons for the delay, the borrower’s prior payment record, and the amount of the shortfall in relation to the principal and interest owed. Impairment is measured on a loan by loan basis for commercial and commercial construction loans by either the present value of expected future cash flows discounted at the loan’s effective interest rate, the loan’s obtainable market price, or the fair value of the collateral if the loan is collateral dependent. A specific allocation within the allowance for loan losses is established for an impaired loan if its carrying value exceeds its estimated fair value. The estimated fair values of the Corporation’s impaired loans are measured based on the estimated fair value of the loan’s collateral or the discounted cash flows method. It is the policy of the Corporation to order an updated valuation on all real estate secured loans when the loan becomes 90 days past due and there has not been an updated valuation completed within the previous 12 months . In addition, the Corporation orders third-party valuations on all impaired real estate collateralized loans within 30 days of the loan being classified as impaired. Until the valuations are completed, the Corporation utilizes the most recent independent third-party real estate valuation to estimate the need for a specific allocation to be assigned to the loan. These existing valuations are discounted downward to account for such things as the age of the existing collateral valuation, change in the condition of the real estate, change in local market and economic conditions, and other specific factors involving the collateral. Once the updated valuation is completed, the collateral value is updated accordingly. For commercial and industrial loans secured by non-real estate collateral, such as accounts receivable, inventory and equipment, estimated fair values are determined based on the borrower’s financial statements, inventory reports, accounts receivable aging reports, equipment appraisals, or invoices. Indications of value from these sources are generally discounted based on the age of the financial information or the quality of the assets. The Corporation actively monitors the values of collateral as well as the age of the valuation of impaired loans. The Corporation orders valuations at least every 18 months , or more frequently if management believes that there is an indication that the fair value has declined. For impaired loans secured by collateral other than real estate, the Corporation considers the net book value of the collateral, as recorded in the most recent financial statements of the borrower, and determines fair value based on estimates made by management. Large groups of smaller balance homogeneous loans are collectively evaluated for impairment. Accordingly, the Corporation does not separately identify individual consumer and residential loans for impairment disclosures, unless such loans are the subject of a troubled debt restructure. Loans whose terms are modified are classified as troubled debt restructured loans if the Corporation grants such borrowers concessions that it would not otherwise consider and it is deemed that those borrowers are experiencing financial difficulty. Concessions granted under a troubled debt restructuring generally involve a temporary reduction in interest rate, a below market interest rate given the risk associated with the loan, or an extension of a loan’s stated maturity date. Nonaccrual troubled debt restructurings may be restored to accrual status if principal and interest payments, under the modified terms, are current for a sustained period of time and, based on a well-documented credit evaluation of the borrower’s financial condition, there is reasonable assurance of repayment. Loans classified as troubled debt restructurings are generally designated as impaired. The allowance calculation methodology includes further segregation of loan classes into credit quality rating categories. The borrower’s overall financial condition, repayment sources, guarantors, and value of collateral, if appropriate, are generally evaluated annually for commercial loans or when credit deficiencies arise, such as delinquent loan payments. Credit quality risk ratings include regulatory classifications of special mention, substandard, doubtful and loss. Loans classified special mention have potential weaknesses that deserve management’s close attention. If uncorrected, the potential weaknesses may result in deterioration of the repayment prospects. Loans classified substandard have a well-defined weakness or weaknesses that jeopardize the liquidation of the debt. They include loans that are inadequately protected by the current sound net worth and paying capacity of the obligor or of the collateral pledged, if any. Loans classified doubtful have all the weaknesses inherent in loans classified substandard with the added characteristic that collection or liquidation in full, on the basis of current conditions and facts, is highly improbable. Loans classified as a loss are considered uncollectible and are charged to the allowance for loan losses. Loans not classified are rated pass. In addition, federal and state regulatory agencies, as an integral part of their examination process, periodically review the Corporation’s allowance for loan losses and may require the Corporation to recognize additions to the allowance based on their judgments about information available to them at the time of their examination, which may not be currently available to management. Based on management’s comprehensive analysis of the loan portfolio and economic conditions, management believes the current level of the allowance for loan losses is adequate. Commercial and Industrial Lending — The Corporation originates commercial and industrial loans primarily to businesses located in its primary market area and surrounding areas. These loans are used for various business purposes which include short-term loans and lines of credit to finance machinery and equipment purchases, inventory, and accounts receivable. Generally, the maximum term for loans extended on machinery and equipment is based on the projected useful life of such machinery and equipment. Most business lines of credit are written on demand and may be renewed annually. Commercial and industrial loans are generally secured with short-term assets; however, in many cases, additional collateral such as real estate is provided as additional security for the loan. Loan-to-value maximum values have been established by the Corporation and are specific to the type of collateral. Collateral values may be determined using invoices, inventory reports, accounts receivable aging reports, collateral appraisals, etc. In underwriting commercial and industrial loans, an analysis is performed to evaluate the borrower’s character and capacity to repay the loan, the adequacy of the borrower’s capital and collateral, as well as the conditions affecting the borrower. Evaluation of the borrower’s past, present and future cash flows is also an important aspect of the Corporation’s analysis. Commercial loans generally present a higher level of risk than other types of loans due primarily to the effect of general economic conditions. Commercial Real Estate Lending — The Corporation engages in commercial real estate lending in its primary market area and surrounding areas. The Corporation’s commercial loan portfolio is secured primarily by commercial retail space, office buildings, and hotels. Generally, commercial real estate loans have terms that do not exceed 20 years , have loan-to-value ratios of up to 80% of the appraised value of the property, and are typically secured by personal guarantees of the borrowers. In underwriting these loans, the Corporation performs a thorough analysis of the financial condition of the borrower, the borrower’s credit history, and the reliability and predictability of the cash flow generated by the property securing the loan. Appraisals on properties securing commercial real estate loans originated by the Corporation are performed by independent appraisers. Commercial real estate loans generally present a higher level of risk than other types of loans due primarily to the effect of general economic conditions and the complexities involved in valuing the underlying collateral. Commercial Real Estate Construction Lending — The Corporation engages in commercial real estate construction lending in its primary market area and surrounding areas. The Corporation’s commercial real estate construction lending consists of commercial and residential site development loans, as well as commercial building construction and residential housing construction loans. The Corporation’s commercial real estate construction loans are generally secured with the subject property. Terms of construction loans depend on the specifics of the project, such as estimated absorption rates, estimated time to complete, etc. In underwriting commercial real estate construction loans, the Corporation performs a thorough analysis of the financial condition of the borrower, the borrower’s credit history, and the reliability and predictability of the cash flow generated by the project using feasibility studies, market data, etc. Appraisals on properties securing commercial real estate construction loans originated by the Corporation are performed by independent appraisers. Commercial real estate construction loans generally present a higher level of risk than other types of loans due primarily to the effect of general economic conditions and the uncertainties surrounding total construction costs. Residential Mortgage Lending — One-to-four family residential mortgage loan originations, including home equity closed-end loans, are generated by the Corporation’s marketing efforts, its present customers, walk-in customers, and referrals. These loans originate primarily within the Corporation’s market area or with customers primarily from the market area. The Corporation offers fixed-rate and adjustable-rate mortgage loans with terms up to a maximum of 30 years for both permanent structures and those under construction. The Corporation’s one-to-four family residential mortgage originations are secured primarily by properties located in its primary market area and surrounding areas. The majority of the Corporation’s residential mortgage loans originate with a loan-to-value of 80% or less. Loans in excess of 80% are required to have private mortgage insurance. In underwriting one-to-four family residential real estate loans, the Corporation evaluates both the borrower’s financial ability to repay the loan as agreed and the value of the property securing the loan. Properties securing real estate loans made by the Corporation are appraised by independent appraisers. The Corporation generally requires borrowers to obtain an attorney’s title opinion or title insurance, as well as fire and property insurance (including flood insurance, if necessary) in an amount not less than the amount of the loan. The Corporation has not engaged in subprime residential mortgage originations. Residential mortgage loans are subject to risk due primarily to general economic conditions, as well as a continued weak housing market. Home Equity Lines of Credit Lending — The Corporation originates home equity lines of credit primarily within the Corporation’s market area or with customers primarily from the market area. Home equity lines of credit are generated by the Corporation’s marketing efforts, its present customers, walk-in customers, and referrals. Home equity lines of credit are secured by the borrower’s primary residence with a maximum loan-to-value of 90% and a maximum term of 20 years . In underwriting home equity lines of credit, the Corporation evaluates both the value of the property securing the loan and the borrower’s financial ability to repay the loan as agreed. The ability to repay is determined by the borrower’s employment history, current financial condition, and credit background. Home equity lines of credit generally present a moderate level of risk due primarily to general economic conditions, as well as a continued weak housing market. Junior liens inherently have more credit risk by virtue of the fact that another financial institution may have a higher security position in the case of foreclosure liquidation of collateral to extinguish the debt. Generally, foreclosure actions could become more prevalent if the real estate market continues to be weak and property values deteriorate. Consumer Lending — The Corporation offers a variety of secured and unsecured consumer loans, including those for vehicles and mobile homes and loans secured by savings deposits. These loans originate primarily within the Corporation’s market area or with customers primarily from the market area. Consumer loan terms vary according to the type and value of collateral and the creditworthiness of the borrower. In underwriting consumer loans, a thorough analysis of the borrower’s financial ability to repay the loan as agreed is performed. The ability to repay is determined by the borrower’s employment history, current financial condition, and credit background. Consumer loans may entail greater credit risk than residential mortgage loans or home equity lines of credit, particularly in the case of consumer loans which are unsecured or are secured by rapidly depreciable assets such as automobiles or recreational equipment. In such cases, any repossessed collateral for a defaulted consumer loan may not provide an adequate source of repayment of the outstanding loan balance as a result of the greater likelihood of damage, loss or depreciation. In addition, consumer loan collections are dependent on the borrower’s continuing financial stability, and thus are more likely to be affected by adverse personal circumstances. Furthermore, the application of various federal and state laws, including bankruptcy and insolvency laws, may limit the amount which can be recovered on such loans. Acquired Loans Acquired Loans (impaired and non-impaired) are initially recorded at their acquisition-date fair values using Level 3 inputs. Fair values are based on a discounted cash flow methodology that involves assumptions and judgments as to credit risk, expected lifetime losses, environmental factors, collateral values, discount rates, expected payments and expected prepayments. Specifically, the Corporation has prepared three separate loan fair value adjustments that it believed a market participant might employ in estimating the entire fair value adjustment necessary under ASC 820-10 for the acquired loan portfolio. The three-separate fair valuation methodology employed are: 1) an interest rate loan fair value adjustment, 2) a general credit fair value adjustment, and 3) a specific credit fair value adjustment for purchased credit impaired loans subject to ASC 310-30 procedures. The carryover of allowance for loan losses related to acquired loans is prohibited as any credit losses in the loans are included in the determination of the fair value of the loans at the acquisition date. The allowance for loan losses on acquired loans reflects only those losses incurred after acquisition and represents the present value of cash flows expected at acquisition that is no longer expected to be collected. Acquired loans are marked to fair value on the date of acquisition. In conjunction with the quarterly evaluation of the adequacy of the allowance for loan losses, the Corporation performs an analysis on acquired loans to determine whether or not there has been subsequent deterioration in relation to those loans. If deterioration has occurred, the Corporation will include these loans in the calculation of the allowance for loan losses after the initial valuation, and provide accordingly. Upon acquisition, in accordance with US GAAP, the Corporation has individually determined whether each acquired loan is within the scope of ASC 310-30. The Corporation’s senior lending management reviewed the accounting seller’s loan portfolio on a loan by loan basis to determine if any loans met the two-part definition of an impaired loan as defined by ASC 310-30: 1) Credit deterioration on the loan from its inception until the acquisition date, and 2) It is probable that not all of the contractual cash flows will be collected on the loan. Acquired ASC 310-20 loans, which are loans that did not meet the criteria above, were pooled into groups of similar loans based on various factors including borrower type, loan purpose, and collateral type. For these pools, the Corporation used certain loan information, including outstanding principal balance, estimated expected losses, weighted average maturity, weighted average margin, and weighted average interest rate along with estimated prepayment rates, expected lifetime losses, environment factors to estimate the expected cash flow for each loan pool. With regards to ASC 310-30 loans, for external disclosure purposes, the aggregate contractual cash flows less the aggregate expected cash flows resulted in a credit related non-accretable yield amount. The aggregate expected cash flows less the acquisition date fair value resulted in an accretable yield amount. The accretable yield reflects the contractual cash flows management expects to

RESTRICTIONS ON CASH AND DUE FR

RESTRICTIONS ON CASH AND DUE FROM BANKS	12 Months Ended
	Dec. 31, 2019
Restricted Cash and Investments [Abstract]
RESTRICTIONS ON CASH AND DUE FROM BANKS	RESTRICTIONS ON CASH AND DUE FROM BANKS In return for services obtained through correspondent banks, the Corporation is required to maintain non-interest bearing cash balances in those correspondent banks. At December 31, 2019 and 2018 , compensating balances approximated $2,276,000 and $1,880,000 , respectively. During 2019 and 2018 , average compensating balances approximated $2,228,000 and $2,073,000 , respectively. All compensating balances are met by vault cash.

SECURITIES

SECURITIES	12 Months Ended
	Dec. 31, 2019
Investments, Debt and Equity Securities [Abstract]
SECURITIES	SECURITIES Amortized cost and fair value at December 31, 2019 and 2018 , were as follows: In thousands Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value SECURITIES AVAILABLE FOR SALE December 31, 2019 U.S. Government and agencies $ 113,569 $ 849 $ 169 $ 114,249 Mortgage-backed securities, residential 64,699 980 87 65,592 State and municipal 10,940 70 14 10,996 $ 189,208 $ 1,899 $ 270 $ 190,837 December 31, 2018 U.S. Government and agencies $ 120,420 $ 142 $ 2,149 $ 118,413 Mortgage-backed securities, residential 33,960 194 343 33,811 State and municipal 9,482 60 36 9,506 $ 163,862 $ 396 $ 2,528 $ 161,730 SECURITIES HELD TO MATURITY December 31, 2019 U.S. Government and agencies $ 4,000 $ 8 $ — $ 4,008 Mortgage-backed securities, residential 15,234 76 37 15,273 $ 19,234 $ 84 $ 37 $ 19,281 December 31, 2018 U.S. Government and agencies $ 7,000 $ — $ 69 $ 6,931 Mortgage-backed securities, residential 20,266 4 290 19,980 $ 27,266 $ 4 $ 359 $ 26,911 The Corporation adopted ASU 2016-01, Financial Instruments—Overall (Topic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities effective January 1, 2018. The required fair value disclosures are as follows: In thousands Fair Value at January 1, 2019 Unrealized Gains Unrealized Losses Fair Value at December 31, 2019 DECEMBER 31, 2019 CRA Mutual Fund $ 1,012 $ 33 $ — $ 1,045 Stock in other banks 827 234 — 1,061 $ 1,839 $ 267 $ — $ 2,106 In thousands Fair Value at January 1, 2018 Unrealized Gains Unrealized Losses Fair Value at December 31, 2018 DECEMBER 31, 2018 CRA Mutual Fund $ 1,044 $ — $ 32 $ 1,012 Stock in other banks 749 247 169 827 $ 1,793 $ 247 $ 201 $ 1,839 The following table shows the Corporation’s investments’ gross unrealized losses and fair value, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position, at December 31, 2019 and 2018 : Less than 12 Months 12 Months or More Total In thousands Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses SECURITIES AVAILABLE FOR SALE December 31, 2019 U.S. Government and agencies $ — $ — $ 47,425 $ 169 $ 47,425 $ 169 Mortgage-backed securities, residential 16,208 82 1,424 5 17,632 87 State and municipal 3,233 13 502 1 3,735 14 $ 19,441 $ 95 $ 49,351 $ 175 $ 68,792 $ 270 December 31, 2018 U.S. Government and agencies $ 1,997 $ 5 $ 87,216 $ 2,144 $ 89,213 $ 2,149 Mortgage-backed securities, residential 9,410 134 8,586 209 17,996 343 State and municipal — — 2,696 36 2,696 36 $ 11,407 $ 139 $ 98,498 $ 2,389 $ 109,905 $ 2,528 SECURITIES HELD TO MATURITY December 31, 2019 Mortgage-backed securities, residential $ 6,587 $ 24 $ 3,161 $ 13 $ 9,748 $ 37 $ 6,587 $ 24 $ 3,161 $ 13 $ 9,748 $ 37 December 31, 2018 U.S. Government and agencies $ 2,975 $ 25 $ 3,956 $ 44 $ 6,931 $ 69 Mortgage-backed security, residential 5,408 59 12,636 231 18,044 290 $ 8,383 $ 84 $ 16,592 $ 275 $ 24,975 $ 359 All mortgage-backed security investments are government sponsored enterprise (GSE) pass-through instruments issued by the Federal National Mortgage Association (FNMA), Government National Mortgage Association (GNMA) or Federal Home Loan Mortgage Corporation (FHLMC), which guarantee the timely payment of principal on these investments. At December 31, 2019 , twenty-five available for sale U.S. Government and agency securities had unrealized losses that individually did not exceed 1% of amortized cost. All of these securities have been in a continuous loss position for 12 months or more. These unrealized losses relate principally to changes in interest rates subsequent to the acquisition of the specific securities. At December 31, 2019 , thirteen available for sale residential mortgage-backed securities had unrealized losses that individually did not exceed 2% of amortized cost. Two of these securities have been in a continuous loss position for 12 months or more. These unrealized losses relate principally to changes in interest rates subsequent to the acquisition of the specific securities. At December 31, 2019 , six available for sale state and municipal securities had unrealized losses that individually did not exceed 1% of amortized cost. One of these securities have been in a continuous loss position for 12 months or more. This unrealized loss relates principally to changes in interest rates subsequent to the acquisition of the specific security. At December 31, 2019 , nineteen held to maturity residential mortgage-backed securities had unrealized losses that individually did not exceed 2% of amortized cost. Eight of these securities have been in a continuous loss position for 12 months or more. These unrealized losses relate principally to changes in interest rates subsequent to the acquisition of the specific securities. In analyzing the issuer’s financial condition, management considers industry analysts’ reports, financial performance, and projected target prices of investment analysts within a one-year time frame. Based on the above information, management has determined that none of these investments are other-than-temporarily impaired. The fair values of securities available for sale (carried at fair value) and held to maturity (carried at amortized cost) are determined by obtaining quoted market prices on nationally recognized securities exchanges (Level 1), or matrix pricing (Level 2), which is a mathematical technique used widely in the industry to value debt securities without relying exclusively on quoted market prices for the specific securities but rather by relying on the security’s relationship to other benchmark quoted prices. The Corporation uses independent service providers to provide matrix pricing. Management routinely sells securities from its available for sale portfolio in an effort to manage and allocate the portfolio. At December 31, 2019 , management had not identified any securities with an unrealized loss that it intends to sell or will be required to sell. In estimating other-than-temporary impairment losses on debt securities, management considers (1) whether management intends to sell the security, or (2) if it is more likely than not that management will be required to sell the security before recovery, or (3) if management does not expect to recover the entire amortized cost basis. In assessing potential other-than-temporary impairment for equity securities, consideration is given to management’s intention and ability to hold the securities until recovery of unrealized losses. Amortized cost and fair value at December 31, 2019 , by contractual maturity, where applicable, are shown below. Expected maturities will differ from contractual maturities because issuers may have the right to call or prepay with or without penalties. Available for Sale Held to Maturity In thousands Amortized Cost Fair Value Amortized Cost Fair Value 1 year or less $ 20,926 $ 20,953 $ 4,000 $ 4,008 Over 1 year through 5 years 98,502 99,220 — — Over 5 years through 10 years 199 202 — — Over 10 years 4,882 4,870 — — Mortgage-backed securities, residential 64,699 65,592 15,234 15,273 $ 189,208 $ 190,837 $ 19,234 $ 19,281 The Corporation realized gross gains of $0 during 2019 and $288,000 during 2018 , and gross losses of $0 during 2019 and $203,000 during 2018 on sales of securities available for sale. At December 31, 2019 and 2018 , securities with a carrying value of $162,946,000 and $165,792,000 , respectively, were pledged as collateral as required by law on public and trust deposits, repurchase agreements, and for other purposes.

LOANS AND ALLOWANCE FOR LOAN LO

LOANS AND ALLOWANCE FOR LOAN LOSSES	12 Months Ended
	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable, Gross, Allowance, and Net [Abstract]
LOANS AND ALLOWANCE FOR LOAN LOSSES	LOANS AND ALLOWANCE FOR LOAN LOSSES The Corporation grants commercial, residential, and consumer loans to customers primarily within southcentral Pennsylvania and northern Maryland and the surrounding area. A large portion of the loan portfolio is secured by real estate. Although the Bank has a diversified loan portfolio, its debtors’ ability to honor their contracts is influenced by the region’s economy. The following tables present the classes of the loan portfolio summarized by the aggregate pass rating and the classified ratings of special mention, substandard and doubtful within the Corporation’s internal risk rating system as of December 31, 2019 and 2018 : In thousands Pass Special Substandard Doubtful Total December 31, 2019 Originated Loans Commercial and industrial $ 132,791 $ 12,249 $ 716 $ — $ 145,756 Commercial real estate 414,077 28,264 9,595 — 451,936 Commercial real estate construction 22,905 1,272 — — 24,177 Residential mortgage 364,814 6,279 251 — 371,344 Home equity lines of credit 92,372 627 83 — 93,082 Consumer 13,331 — — — 13,331 Total Originated Loans 1,040,290 48,691 10,645 — 1,099,626 Acquired Loans Commercial and industrial 3,007 374 178 — 3,559 Commercial real estate 100,199 11,537 3,376 — 115,112 Commercial real estate construction 1,542 697 — — 2,239 Residential mortgage 33,349 2,089 1,555 — 36,993 Home equity lines of credit 14,603 45 317 — 14,965 Consumer 107 — — — 107 Total Acquired Loans 152,807 14,742 5,426 — 172,975 Total Loans Commercial and industrial 135,798 12,623 894 — 149,315 Commercial real estate 514,276 39,801 12,971 — 567,048 Commercial real estate construction 24,447 1,969 — — 26,416 Residential mortgage 398,163 8,368 1,806 — 408,337 Home equity lines of credit 106,975 672 400 — 108,047 Consumer 13,438 — — — 13,438 Total Loans $ 1,193,097 $ 63,433 $ 16,071 $ — $ 1,272,601 In thousands Pass Special Substandard Doubtful Total December 31, 2018 Originated Loans Commercial and industrial $ 166,035 $ 2,902 $ 161 $ — $ 169,098 Commercial real estate 393,987 18,079 7,899 — 419,965 Commercial real estate construction 15,471 835 — — 16,306 Residential mortgage 381,525 6,492 733 — 388,750 Home equity lines of credit 90,941 334 — — 91,275 Consumer 14,174 — — — 14,174 Total Originated Loans 1,062,133 28,642 8,793 — 1,099,568 Acquired Loans Commercial and industrial 4,803 134 147 — 5,084 Commercial real estate 120,321 5,112 3,525 — 128,958 Commercial real estate construction 3,276 716 — — 3,992 Residential mortgage 41,193 1,896 2,460 — 45,549 Home equity lines of credit 18,614 88 386 — 19,088 Consumer 226 — — — 226 Total Acquired Loans 188,433 7,946 6,518 — 202,897 Total Loans Commercial and industrial 170,838 3,036 308 $ — 174,182 Commercial real estate 514,308 23,191 11,424 — 548,923 Commercial real estate construction 18,747 1,551 — — 20,298 Residential mortgage 422,718 8,388 3,193 — 434,299 Home equity lines of credit 109,555 422 386 — 110,363 Consumer 14,400 — — — 14,400 Total Loans $ 1,250,566 $ 36,588 $ 15,311 $ — $ 1,302,465 The following table provides changes in accretable yield for all acquired loans accounted for under ASC 310-30. Loans accounted for under ASC 310-20 are not included in this table. In thousands Year Ended December 31, 2019 Year Ended December 31, 2018 Balance at beginning of period $ 891 $ 1,234 Acquisitions of impaired loans — — Reclassification from non-accretable differences 492 402 Accretion to loan interest income (741 ) (745 ) Balance at end of period $ 642 $ 891 Cash flows expected to be collected on acquired loans are estimated quarterly by incorporating several key assumptions similar to the initial estimate of fair value. These key assumptions include probability of default and the amount of actual prepayments after the acquisition date. Prepayments affect the estimated life of the loans and could change the amount of interest income, and possibly principal expected to be collected. In reforecasting future estimated cash flows, credit loss expectations are adjusted as necessary. Improved cash flow expectations for loans or pools are recorded first as a reversal of previously recorded impairment, if any, and then as an increase in prospective yield when all previously recorded impairment has been recaptured. Decreases in expected cash flows are recognized as impairment through a charge to the provision for loan losses and credit to the allowance for loan losses. The following table summarizes information relative to impaired loans by loan portfolio class as of December 31, 2019 and 2018 : Impaired Loans with Allowance Impaired Loans with No Allowance In thousands Recorded Investment Unpaid Principal Balance Related Allowance Recorded Investment Unpaid Principal Balance December 31, 2019 Commercial and industrial $ 65 $ 65 $ 42 $ — $ — Commercial real estate — — — 7,383 7,383 Commercial real estate construction — — — — — Residential mortgage — — — 171 171 Home equity lines of credit — — — 83 83 Total $ 65 $ 65 $ 42 $ 7,637 $ 7,637 December 31, 2018 Commercial and industrial $ — $ — $ — $ — $ — Commercial real estate — — — 6,763 6,763 Commercial real estate construction — — — — — Residential mortgage — — — 537 537 Home equity lines of credit — — — — — Total $ — $ — $ — $ 7,300 $ 7,300 The following table summarizes information in regards to average of impaired loans and related interest income by loan portfolio class: Impaired Loans with Allowance Impaired Loans with No Allowance In thousands Average Recorded Investment Interest Income Average Recorded Investment Interest Income December 31, 2019 Commercial and industrial $ 27 $ — $ — $ — Commercial real estate — — 6,625 612 Commercial real estate construction — — — — Residential mortgage — — 422 8 Home equity lines of credit — — 35 — Total $ 27 $ — $ 7,082 $ 620 December 31, 2018 Commercial and industrial $ 436 $ — $ 73 $ 44 Commercial real estate — — 7,372 216 Commercial real estate construction — — — — Residential mortgage 75 — 275 — Home equity lines of credit 30 — — — Total $ 541 $ — $ 7,720 $ 260 No additional funds are committed to be advanced in connection with impaired loans. If interest on all nonaccrual loans had been accrued at original contract rates, interest income would have increased by $249,000 in 2019 and $269,000 in 2018 . The following table presents nonaccrual loans by loan portfolio class as of December 31, 2019 and 2018 , the table below excludes $6.9 million in purchase credit impaired loans, net of unamortized fair value adjustments: In thousands 2019 2018 Commercial and industrial $ 65 $ — Commercial real estate 3,600 2,880 Commercial real estate construction — — Residential mortgage 171 537 Home equity lines of credit 83 — Total $ 3,919 $ 3,417 There were no loans whose terms have been modified resulting in a troubled debt restructuring during the years ended December 31, 2019 and 2018 . The Corporation classifies certain loans as troubled debt restructurings when credit terms to a borrower in financial difficulty are modified. The modifications may include a reduction in rate, an extension in term and/or the restructuring of scheduled principal payments. The Corporation had pre-existing nonaccruing and accruing troubled debt restructurings of $3,974,000 and $6,226,000 at December 31, 2019 and 2018 , respectively. All of the Corporation’s troubled debt restructured loans are also impaired loans, of which some have resulted in a specific allocation and, subsequently, a charge-off as appropriate. Included in the non-accrual loan total at December 31, 2019 and 2018 , were $191,000 and $2,343,000 , respectively, of troubled debt restructurings. In addition to the troubled debt restructurings included in non-accrual loans, the Corporation also has loans classified as accruing troubled debt restructurings at December 31, 2019 and 2018 , which total $3,783,000 and $3,883,000 , respectively. There were no defaulted troubled debt restructured loans as of December 31, 2019 and 2018 . There were no charge-offs on any of the troubled debt restructured loans for the years ended December 31, 2019 and 2018 . There were no specific allocations on any troubled debt restructured loans for the years ended December 31, 2019 and 2018 . One troubled debt restructured loan paid off during 2019 in the amount of $2,198,000 and one troubled debt restructured loan paid off during 2018 in the amount of $832,000 . All other troubled debt restructured loans were current as of December 31, 2019 , with respect to their associated forbearance agreement, except for one loan which has had periodic late payments. As of December 31, 2019 , there are no active forbearance agreements. All forbearance agreements have expired or the loans have paid off. Consumer mortgage loans secured by residential real estate properties for which formal foreclosure proceedings are in process at December 31, 2019 and 2018 , totaled $822,000 and $661,000 , respectively. The performance and credit quality of the loan portfolio is also monitored by analyzing the age of the loans receivable as determined by the length of time a recorded payment is past due. The following table presents the classes of the loan portfolio summarized by the past due status as of December 31, 2019 and 2018 : In thousands 30-59 Days Past Due 60-89 Days Past Due >90 Days Past Due Total Past Due Current Total Loans Receivable Loans Receivable >90 Days and Accruing December 31, 2019 Originated Loans Commercial and industrial $ 16 $ — $ 4 $ 20 $ 145,736 $ 145,756 $ 4 Commercial real estate 325 2,247 1,286 3,858 448,078 451,936 — Commercial real estate construction 78 — — 78 24,099 24,177 — Residential mortgage 1,625 949 1,232 3,806 367,538 371,344 1,061 Home equity lines of credit 141 77 — 218 92,864 93,082 — Consumer 38 8 19 65 13,266 13,331 19 Total originated loans 2,223 3,281 2,541 8,045 1,091,581 1,099,626 1,084 Acquired Loans Commercial and industrial — 23 — 23 3,536 3,559 — Commercial real estate 1,063 — — 1,063 114,049 115,112 — Commercial real estate construction — — — — 2,239 2,239 — Residential mortgage 293 257 120 670 36,323 36,993 120 Home equity lines of credit 236 93 15 344 14,621 14,965 15 Consumer — — — — 107 107 — Total acquired loans 1,592 373 135 2,100 170,875 172,975 135 Total Loans Commercial and industrial 16 23 4 43 149,272 149,315 4 Commercial real estate 1,388 2,247 1,286 4,921 562,127 567,048 — Commercial real estate construction 78 — — 78 26,338 26,416 — Residential mortgage 1,918 1,206 1,352 4,476 403,861 408,337 1,181 Home equity lines of credit 377 170 15 562 107,485 108,047 15 Consumer 38 8 19 65 13,373 13,438 19 Total Loans $ 3,815 $ 3,654 $ 2,676 $ 10,145 $ 1,262,456 $ 1,272,601 $ 1,219 In thousands 30-59 Days Past Due 60-89 Days Past Due >90 Days Past Due Total Past Due Current Total Loans Receivable Loans Receivable >90 Days and Accruing December 31, 2018 Originated Loans Commercial and industrial $ 49 $ 49 $ 4 $ 102 $ 168,996 $ 169,098 $ 4 Commercial real estate 775 550 114 1,439 418,526 419,965 — Commercial real estate construction — — — — 16,306 16,306 — Residential mortgage 1,783 529 2,361 4,673 384,077 388,750 1,824 Home equity lines of credit 16 38 375 429 90,846 91,275 375 Consumer 36 14 — 50 14,124 14,174 — Total originated loans 2,659 1,180 2,854 6,693 1,092,875 1,099,568 2,203 Acquired Loans Commercial and industrial 27 — — 27 5,057 5,084 — Commercial real estate 64 — 851 915 128,043 128,958 851 Commercial real estate construction 343 — 77 420 3,572 3,992 77 Residential mortgage 1,235 251 907 2,393 43,156 45,549 125 Home equity lines of credit 227 — 89 316 18,772 19,088 89 Consumer — 7 — 7 219 226 — Total acquired loans 1,896 258 1,924 4,078 198,819 202,897 1,142 Total Loans Commercial and industrial 76 49 4 129 174,053 174,182 4 Commercial real estate 839 550 965 2,354 546,569 548,923 851 Commercial real estate construction 343 — 77 420 19,878 20,298 77 Residential mortgage 3,018 780 3,268 7,066 427,233 434,299 1,949 Home equity lines of credit 243 38 464 745 109,618 110,363 464 Consumer 36 21 — 57 14,343 14,400 — Total Loans $ 4,555 $ 1,438 $ 4,778 $ 10,771 $ 1,291,694 $ 1,302,465 $ 3,345 The following table summarizes the allowance for loan losses and recorded investment in loans: In thousands Commercial and Industrial Commercial Real Estate Commercial Real Estate Construction Residential Mortgage Home Equity Lines of Credit Consumer Unallocated Total December 31, 2019 Allowance for loan losses Beginning balance- January 1, 2019 $ 2,597 $ 6,208 $ 203 $ 2,814 $ 611 $ 692 $ 839 $ 13,964 Charge-offs (163 ) (78 ) — (173 ) (301 ) (202 ) — (917 ) Recoveries 66 10 — 37 12 63 — 188 Provisions (100 ) 553 95 (123 ) 297 97 (219 ) 600 Ending balance- December 31, 2019 $ 2,400 $ 6,693 $ 298 $ 2,555 $ 619 $ 650 $ 620 $ 13,835 Ending balance: individually evaluated for impairment $ 42 $ — $ — $ — $ — $ — $ — $ 42 Ending balance: collectively evaluated for impairment $ 2,358 $ 6,693 $ 298 $ 2,555 $ 619 $ 650 $ 620 $ 13,793 Loans receivables Ending balance $ 149,315 $ 567,048 $ 26,416 $ 408,337 $ 108,047 $ 13,438 $ — $ 1,272,601 Ending balance: individually evaluated for impairment $ 65 $ 7,383 $ — $ 171 $ 83 $ — $ — $ 7,702 Ending balance: collectively evaluated for impairment $ 149,250 $ 559,665 $ 26,416 $ 408,166 $ 107,964 $ 13,438 $ — $ 1,264,899 December 31, 2018 Allowance for loan losses Beginning balance- January 1, 2018 $ 3,219 $ 5,228 $ 126 $ 3,226 $ 612 $ 749 $ 816 $ 13,976 Charge-offs (934 ) (33 ) — (530 ) (148 ) (165 ) — (1,810 ) Recoveries 36 — 103 32 — 7 — 178 Provisions 276 1,013 (26 ) 86 147 101 23 1,620 Ending balance- December 31, 2018 $ 2,597 $ 6,208 $ 203 $ 2,814 $ 611 $ 692 $ 839 $ 13,964 Ending balance: individually evaluated for impairment $ — $ — $ — $ — $ — $ — $ — $ — Ending balance: collectively evaluated for impairment $ 2,597 $ 6,208 $ 203 $ 2,814 $ 611 $ 692 $ 839 $ 13,964 Loans receivables Ending balance $ 174,182 $ 548,923 $ 20,298 $ 434,299 $ 110,363 $ 14,400 $ — $ 1,302,465 Ending balance: individually evaluated for impairment $ — $ 6,763 $ — $ 537 $ — $ — $ — $ 7,300 Ending balance: collectively evaluated for impairment $ 174,182 $ 542,160 $ 20,298 $ 433,762 $ 110,363 $ 14,400 $ — $ 1,295,165 The Bank has granted loans to certain of its executive officers, directors and their related interests. These loans were made on substantially the same basis, including interest rates and collateral as those prevailing for comparable transactions with other borrowers at the same time. The aggregate amount of these loans was $5,016,000 and $5,858,000 at December 31, 2019 and 2018 , respectively. During 2019 , no new loans or advances were extended and repayments totaled $843,000 . None of these loans were past due, in nonaccrual status, or restructured at December 31, 2019 .

PREMISES AND EQUIPMENT

PREMISES AND EQUIPMENT	12 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
PREMISES AND EQUIPMENT	PREMISES AND EQUIPMENT Premises and equipment at December 31 were as follows: In thousands 2019 2018 Land $ 5,050 $ 5,050 Buildings and improvements 27,915 27,509 Furniture and equipment 14,562 14,111 Construction in process 928 460 48,455 47,130 Accumulated depreciation (22,731 ) (20,721 ) $ 25,724 $ 26,409 Depreciation expense was $2,076,000 and $2,108,000 for the years ended December 31, 2019 and 2018 , respectively.

INVESTMENTS IN LOW-INCOME HOUSI

INVESTMENTS IN LOW-INCOME HOUSING PARTNERSHIPS	12 Months Ended
	Dec. 31, 2019
Real Estate Partnership Investment Subsidiaries, Net Income (Loss) before Tax [Abstract]
INVESTMENTS IN LOW-INCOME HOUSING PARTNERSHIPS	INVESTMENTS IN LOW-INCOME HOUSING PARTNERSHIPS ACNB Corporation is a limited partner in three partnerships, whose purpose is to develop, manage and operate residential low-income properties. At December 31, 2019 and 2018 , the carrying value of these investments was approximately $1,506,000 and $1,871,000 , respectively.

DEPOSITS

DEPOSITS	12 Months Ended
	Dec. 31, 2019
Interest-bearing Deposit Liabilities [Abstract]
DEPOSITS	DEPOSITS Deposits were comprised of the following as of December 31: In thousands 2019 2018 Non-interest bearing demand $ 314,377 $ 302,394 Interest bearing demand 152,275 160,718 Savings 537,755 516,872 Time certificates of deposit of $250,000 or less 339,876 307,407 Time certificates of deposit greater than $250,000 67,977 60,701 $ 1,412,260 $ 1,348,092 Scheduled maturities of time certificates of deposit at December 31, 2019 , were as follows: Years Ending In thousands 2020 $ 258,528 2021 109,470 2022 26,627 2023 6,164 2024 7,064 $ 407,853

LEASE COMMITMENTS

LEASE COMMITMENTS	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
LEASE COMMITMENTS	LEASE COMMITMENTS Effective January 1, 2019, the Corporation adopted the new lease accounting standard, ASU 2016-12, using the modified-retrospective method. As such, for reporting periods beginning on or after January 1, 2019, leases are recognized, presented and disclosed in accordance with ASU 2016-02, while periods prior to the adoption date were not adjusted and are reported in accordance with ASC 840, Leases . The Corporation enters into noncancellable lease arrangements primarily for some of its community offices. Certain lease arrangements contain clauses requiring increasing rental payments over the lease term, which are generally contractually stipulated. Many of these lease arrangements provide the Corporation with the option to renew the lease arrangement after the initial lease term. These options are included in determining the lease term used to establish the right-of-use assets and lease liabilities when it is reasonably certain the Corporation will exercise its renewal option. As most of the Corporation’s leases do not have a readily determinable implicit rate, the incremental borrowing rate is primarily used to determine the discount rate for purposes of measuring the right-of-use assets and lease liabilities. The Corporation’s lease arrangements do not contain any material residual value guarantees or material restrictive covenants. The following right-of-use assets and lease liabilities are reported within the consolidated statements of condition as follows: In thousands December 31, 2019 Operating Leases: Right of use assets $ 3,502 Lease liabilities 3,502 Supplemental balance sheet information related to leases was as follows for the year ended December 31, 2019 : Operating Leases: Weighted average remaining lease term 7.1 years Weighted average discount rate 5.71 % The following summarizes the remaining scheduled future minimum lease payments for operating leases as of December 31, 2019 : Years Ending In thousands 2020 $ 756 2021 665 2022 544 2023 480 2024 466 Thereafter 1,685 Total minimum lease payments 4,596 Less: Amount representing interest (1) 1,094 Present value of net minimum lease payments $ 3,502 (1) Amount necessary to reduce net minimum lease payments to present value calculated at the Corporation’s incremental borrowing rate. As of December 31, 2019 , the Corporation does not have any significant additional operating or finance leases that have not yet commenced. The total rent expense for all operating leases was $883,000 and $890,000 for the years ended December 31, 2019 and 2018 , respectively. ACNB leased space at several of its owned offices to other unrelated organizations. Total rental income for these properties was $94,000 and $131,000 for the years ended December 31, 2019 and 2018 , respectively.

BORROWINGS

BORROWINGS	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
BORROWINGS	BORROWINGS Short-term borrowings and weighted-average interest rates at December 31 are as follows: 2019 2018 Dollars in thousands Amount Rate Amount Rate FHLB overnight advance $ — — % $ 32 2.62 % Securities sold under repurchase agreements 33,435 0.12 34,616 0.12 $ 33,435 0.12 % $ 34,648 0.12 % Under an agreement with the FHLB, the Bank has short-term borrowing capacity included within its maximum borrowing capacity. All FHLB advances are collateralized by a security agreement covering qualifying loans and unpledged U.S. Treasury, agency and mortgage-backed securities. In addition, all FHLB advances are secured by the FHLB capital stock owned by the Bank having a par value of $3,375,000 at December 31, 2019 . The Corporation also has lines of credit that total $29,000,000 with correspondent banks for overnight federal funds borrowings. There were no advances on these lines at December 31, 2019 and 2018 . The Corporation enters into agreements under which it sells securities subject to an obligation to repurchase the same or similar securities. Under these arrangements, the Corporation may transfer legal control over the assets but still retain effective control through an agreement that both entitles and obligates the Corporation to repurchase the assets. As a result, these repurchase agreements are accounted for as collateralized financing agreements (i.e., secured borrowings) and not as a sale and subsequent repurchase of securities. The obligation to repurchase the securities is reflected as a liability in the Corporation’s consolidated statements of condition, while the securities underlying the repurchase agreements remain in the respective investment securities asset accounts. In other words, there is no offsetting or netting of the investment securities assets with the repurchase agreement liabilities. In addition, as the Corporation does not enter into reverse repurchase agreements, there is no such offsetting to be done with the repurchase agreements. The right of setoff for a repurchase agreement resembles a secured borrowing, whereby the collateral would be used to settle the fair value of the repurchase agreement should the Corporation be in default (e.g., fails to make an interest payment to the counterparty). For private institution repurchase agreements, if the private institution counterparty were to default (e.g., declare bankruptcy), the Corporation could cancel the repurchase agreement (i.e., cease payment of principal and interest), and attempt collection on the amount of collateral value in excess of the repurchase agreement fair value. The collateral is held by a third-party financial institution in the counterparty’s custodial account. The counterparty has the right to sell or repledge the investment securities. For government entity repurchase agreements, the collateral is held by the Corporation in a segregated custodial account under a tri-party agreement. The following table presents the short-term borrowings subject to an enforceable master netting arrangement or repurchase agreement as of December 31, 2019 and 2018 : Gross Amounts Not Offset in the Statements of Condition Dollars in thousands Gross Amounts of Recognized Liabilities Gross Amounts Offset in the Statements of Condition Net Amounts of Liabilities Presented in the Statements of Condition Financial Instruments Cash Collateral Pledged Net Amount December 31, 2019 Repurchase agreements Commercial customers and government entities (a) $ 33,435 $ — $ 33,435 $ (33,435 ) $ — $ — December 31, 2018 Repurchase agreements Commercial customers and government entities (a) $ 34,616 $ — $ 34,616 $ (34,616 ) $ — $ — (a) As of December 31, 2019 and 2018 , the fair value of securities pledged in connection with repurchase agreements was $34,582,000 and $39,788,000 , respectively. A summary of long-term debt as of December 31 is as follows: 2019 2018 Dollars in thousands Amount Rate Amount Rate FHLB fixed-rate advances maturing: 2019 $ — — % $ 23,500 1.73 % 2020 20,000 1.87 % 20,000 1.87 % 2021 22,716 2.10 % 22,716 2.10 % 2022 11,000 2.69 % 9,000 2.70 % 2023 5,000 2.60 % — — % Loan Payable to local bank 1,830 4.50 % 2,300 4.50 % Loan Payable to local bank 750 4.50 % 1,000 5.25 % Trust preferred subordinated debt 5,000 6.39 % 5,000 6.39 % $ 66,296 2.58 % $ 83,516 2.47 % The FHLB advances are collateralized by the assets defined in the security agreement and FHLB capital stock described previously. The Corporation can borrow a maximum of $703,056,000 from the FHLB, of which $619,881,000 was available at December 31, 2019 . The first loan payable to a local bank has a fixed rate of 4.50% for the first five years and a variable rate of interest with Prime Rate thereafter to final maturity in June 2028. The principal balance of this note may be prepaid at any time without penalty. The second loan payable to a local bank is a commercial revolving line of credit which has a variable rate equal to the Wall Street Journal Prime Rate minus 0.25% , 4.50% at December 31, 2019 . Principal shall be payable when and in amounts demanded by the bank. The principal balance of this note may be prepaid at anytime without penalty. The trust preferred subordinated debt is comprised of debt securities issued by New Windsor in June 2005 and assumed by ACNB Corporation through the acquisition. New Windsor issued $5,000,000 of 6.39% fixed rate capital securities to institutional investors in a private pooled transaction. The proceeds were transferred to New Windsor as trust preferred subordinated debt under the same terms and conditions. The Corporation then contributed the full amount to the Bank in the form of Tier 1 capital. The Corporation has, through various contractual agreements, fully and unconditionally guaranteed all of the trust obligations with respect to the capital securities.

REGULATORY RESTRICTIONS ON DIVI

REGULATORY RESTRICTIONS ON DIVIDENDS	12 Months Ended
	Dec. 31, 2019
Disclosure of Restrictions on Dividends, Loans and Advances Disclosure [Abstract]
REGULATORY RESTRICTIONS ON DIVIDENDS	REGULATORY RESTRICTIONS ON DIVIDENDS Dividend payments by the Bank to the Corporation are subject to the Pennsylvania Banking Code, the Federal Deposit Insurance Act, and the regulations of the FDIC, including final rules to implement the Basel III regulatory capital reforms and changes required by the Dodd-Frank Act. Under the Banking Code, no dividends may be paid except from “accumulated net earnings” (generally, retained earnings). The Federal Reserve Board and the FDIC have formal and informal policies which provide that insured banks and bank holding companies should generally pay dividends only out of current operating earnings, with some exceptions. As of December 31, 2019 , $36,921,000 of undistributed earnings of the Bank, included in consolidated retained earnings, was available for distribution to the Corporation as dividends without prior regulatory approval. Additionally, dividends paid by the Bank to the Corporation would be prohibited if the effect thereof would cause the Bank’s capital to be reduced below applicable minimum capital requirements.

INCOME TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES The components of income tax expense for the years ended December 31, 2019 and 2018 , are as follows: In thousands 2019 2018 Federal: Current $ 5,169 $ 4,036 Deferred 122 388 5,291 4,424 State: Current 338 479 Deferred 16 69 354 548 $ 5,645 $ 4,972 Reconciliations of the statutory federal income tax to the income tax expense reported in the consolidated statements of income for the years ended December 31, 2019 and 2018 , are as follows: Percentage of Income before Income Taxes 2019 2018 Federal income tax at statutory rate 21.0 % 21.0 % State income taxes, net of federal benefit 1.0 % 1.6 % Tax-exempt income (1.5 )% (1.7 )% Earnings on investment in bank-owned life insurance (0.8 )% (0.9 )% Rehabilitation and low-income housing credits (1.0 )% (1.1 )% Reduction of federal tax rate — % — % Other 0.5 % (0.3 )% 19.2 % 18.6 % The provision for federal income taxes includes $0 and $46,000 of income taxes related to net gains on sales of securities in 2019 and 2018 , respectively. Rehabilitation and low-income housing income tax credits were $281,000 and $287,000 , during 2019 and 2018 , respectively. Components of deferred tax assets and liabilities at December 31 were as follows: In thousands 2019 2018 Deferred tax assets: Allowance for loan losses $ 2,995 $ 3,054 Available for sale securities — 409 Accrued deferred compensation 941 884 Pension 2,033 2,207 Other-than-temporary impairment 43 43 Nonaccrual interest 194 192 Deferred director fees 664 589 Acquisition accounting 377 785 Other 604 602 7,851 8,765 Deferred tax liabilities: Deferred loan fees 94 101 Available for sale securities 391 — Prepaid pension benefit cost 4,154 4,289 Prepaid expenses 129 130 Accumulated depreciation 221 347 Goodwill/intangibles 1,181 1,056 6,170 5,923 Net Deferred Tax Asset included in Other Assets $ 1,681 $ 2,842 The Corporation did not have any uncertain tax positions at December 31, 2019 and 2018 . The Corporation’s policy is to recognize interest and penalties on unrecognized tax benefits in income tax expense in the Consolidated Statements of Income. Years that remain open for potential review by the Internal Revenue Service are 2016 through 2019.

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	FAIR VALUE MEASUREMENTS Management uses its best judgment in estimating the fair value of the Corporation’s financial instruments; however, there are inherent weaknesses in any estimation technique. Therefore, for substantially all financial instruments, the fair value estimates herein are not necessarily indicative of the amounts the Corporation could have realized in a sales transaction on the dates indicated. The estimated fair value amounts have been measured as of their respective reporting dates and have not been reevaluated or updated for purposes of these consolidated financial statements subsequent to those respective dates. As such, the estimated fair values of these financial instruments subsequent to the respective reporting dates may be different than the amounts reported at each period end. Fair value measurement and disclosure guidance defines fair value as the price that would be received to sell the asset or transfer the liability in an orderly transaction (that is, not a forced liquidation or distressed sale) between market participants at the measurement date under current market conditions. Fair value measurement and disclosure guidance provides a list of factors that a reporting entity should evaluate to determine whether there has been a significant decrease in the volume and level of activity for the asset or liability in relation to normal market activity for the asset or liability. When the reporting entity concludes there has been a significant decrease in the volume and level of activity for the asset or liability, further analysis of the information from that market is needed and significant adjustments to the related prices may be necessary to estimate fair value in accordance with fair value measurement and disclosure guidance. This guidance further clarifies that when there has been a significant decrease in the volume and level of activity for the asset or liability, some transactions may not be orderly. In those situations, the entity must evaluate the weight of the evidence to determine whether the transaction is orderly. The guidance provides a list of circumstances that may indicate that a transaction is not orderly. A transaction price that is not associated with an orderly transaction is given little, if any, weight when estimating fair value. Fair value measurement and disclosure guidance establishes a fair value hierarchy that prioritizes the inputs to valuation methods used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). The three levels of the fair value hierarchy are as follows: Level 1: Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities. Level 2: Quoted prices in markets that are not active, or inputs that are observable, either directly or indirectly, for substantially the full term of the asset or liability. Level 3: Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported with little or no market activity). An asset or liability’s level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement. For assets measured at fair value, the fair value measurements by level within the fair value hierarchy, and the basis of measurement used at December 31, 2019 and 2018 , are as follows: Fair Value Measurements at December 31, 2019 In thousands Basis Total Level 1 Level 2 Level 3 U.S. Government and agencies $ 114,249 $ — $ 114,249 $ — Mortgage-backed securities, residential 65,592 — 65,592 — State and municipal 10,996 — 10,996 — Total securities available for sale Recurring $ 190,837 $ — $ 190,837 $ — Equity securities with readily determinable fair values Recurring $ 2,106 $ 2,106 $ — $ — Collateral dependent impaired loans Non-recurring $ 3,806 $ — $ — $ 3,806 Fair Value Measurements at December 31, 2018 In thousands Basis Total Level 1 Level 2 Level 3 U.S. Government and agencies $ 118,413 $ — $ 118,413 $ — Mortgage-backed securities, residential 33,811 — 33,811 — State and municipal 9,506 — 9,506 — Total securities available for sale Recurring $ 161,730 $ — $ 161,730 $ — Equity securities with readily determinable fair values Recurring $ 1,839 $ 1,839 $ — $ — Collateral dependent impaired loans Non-recurring $ 3,883 $ — $ — $ 3,883 The following table presents additional quantitative information about assets measured at fair value on a nonrecurring basis for which the Corporation has utilized Level 3 inputs to determine fair value: Quantitative Information about Level 3 Fair Value Measurements Dollars in thousands Fair Value Estimate Valuation Technique Unobservable Input Range Weighted Average December 31, 2019 Impaired loans $ 3,806 Appraisal of collateral (1) Appraisal adjustments (2) (10) - (50)% (15 )% December 31, 2018 Impaired loans $ 3,883 Appraisal of collateral (1) Appraisal adjustments (2) (10) - (50)% (16 )% (1) Fair value is generally determined through management’s estimate or independent third-party appraisals of the underlying collateral, which generally includes various Level 3 inputs which are not observable. (2) Appraisals may be adjusted downward by management for qualitative factors such as economic conditions and estimated liquidation expenses. The range of liquidation expenses and other appraisal adjustments are presented as a percentage of the appraisal. Higher downward adjustments are caused by negative changes to the collateral or conditions in the real estate market, actual offers or sales contracts received, and/or age of the appraisal. The following information should not be interpreted as an estimate of the fair value of the entire Corporation since a fair value calculation is only provided for a limited portion of the Corporation’s assets and liabilities. Due to a wide range of valuation techniques and the degree of subjectivity used in making the estimates, comparisons between the Corporation’s disclosures and those of other companies may not be meaningful. The following presents the carrying amount, fair value, and placement in the fair value hierarchy of the Corporation’s financial instruments at December 31, 2019 : December 31, 2019 In thousands Carrying Amount Fair Value Level 1 Level 2 Level 3 Financial assets: Cash and due from banks $ 16,878 $ 16,878 $ 9,542 $ 7,336 $ — Interest-bearing deposits in banks 97,478 97,478 97,478 — — Equity securities available for sale 2,106 2,106 2,106 — — Investment securities available for sale 190,837 190,837 — 190,837 — Investment securities held to maturity 19,234 19,281 — 19,281 — Loans held for sale 2,406 2,406 — 2,406 — Loans, less allowance for loan losses 1,258,766 1,263,014 — — 1,263,014 Accrued interest receivable 4,368 4,368 — 4,368 — Restricted investment in bank stocks 3,644 3,644 — 3,644 — Financial liabilities: Demand deposits and savings 1,004,407 1,004,407 — 1,004,407 — Time deposits 407,853 409,426 — 409,426 — Short-term borrowings 33,435 33,435 — 33,435 — Long-term borrowings 61,296 61,965 — 61,965 — Trust preferred subordinated debt 5,000 4,711 — 4,711 — Accrued interest payable 2,676 2,676 — 2,676 — Off-balance sheet financial instruments — — — — — The following presents the carrying amount, exit pricing concept fair value, and placement in the fair value hierarchy of the Corporation’s financial instruments at December 31, 2018 : December 31, 2018 In thousands Carrying Amount Fair Value Level 1 Level 2 Level 3 Financial assets: Cash and due from banks $ 20,105 $ 20,105 $ 8,190 $ 11,915 $ — Interest-bearing deposits in banks 20,800 20,800 20,800 — — Equity securities available for sale 1,839 1,839 1,839 — — Investment securities available for sale 161,730 161,730 — 161,730 — Investment securities held to maturity 27,266 26,911 — 26,911 — Loans held for sale 408 408 — 408 — Loans, less allowance for loan losses 1,288,501 1,272,393 — — 1,272,393 Accrued interest receivable 4,545 4,545 — 4,545 — Restricted investment in bank stocks 4,336 4,336 — 4,336 — Financial liabilities: Demand deposits and savings 979,964 979,964 — 979,964 — Time deposits 368,128 364,093 — 364,093 — Short-term borrowings 34,648 34,648 — 34,648 — Long-term borrowings 78,516 78,545 — 78,545 — Trust preferred subordinated debt 5,000 4,701 — 4,701 — Accrued interest payable 1,364 1,364 — 1,364 — Off-balance sheet financial instruments — — — — —

RETIREMENT PLANS

RETIREMENT PLANS	12 Months Ended
	Dec. 31, 2019
Postemployment Benefits [Abstract]
RETIREMENT PLANS	RETIREMENT PLANS The Corporation’s banking subsidiary has a non-contributory, defined benefit pension plan. Retirement benefits are a function of both years of service and compensation. The funding policy is to contribute annually the amount that is sufficient to meet the minimum funding requirements set forth in the Employee Retirement Income Security Act. A measurement date of December 31 has been used for the fiscal years ended December 31, 2019 and 2018 . In thousands 2019 2018 Change in benefit obligation: Benefit obligation at beginning of year $ 30,338 $ 31,547 Service cost 696 860 Interest cost 1,213 1,096 Actuarial loss (gain) 3,603 (1,944 ) Benefits paid (1,316 ) (1,221 ) Projected benefit obligation at end of year 34,534 30,338 Change in plan assets: Fair value of plan assets at beginning of year 39,680 42,439 Actual return on plan assets 5,928 (1,538 ) Employer contribution — — Benefits paid (1,316 ) (1,221 ) Fair value of plan assets at end of year 44,292 39,680 Funded Status, included in other assets $ 9,758 $ 9,342 Amounts recognized in accumulated other comprehensive loss: Total net actuarial loss $ 9,147 $ 9,773 Prior service cost — — Total included in accumulated other comprehensive loss (pretax) $ 9,147 $ 9,773 The estimated costs that will be amortized from accumulated other comprehensive loss into net periodic pension cost during the next fiscal year are as follows: In thousands Net loss $ 675 Prior service cost — $ 675 The accumulated benefit obligation totaled $33,080,000 and $29,115,000 at December 31, 2019 and 2018 , respectively. For the years ended December 31, 2019 and 2018 the mortality assumptions were derived using the mortality rates from RP-2006 (underlying baseline table from SOA RP-2014 study based on experience data for private pension plans of 2006, the central year of experience data 2004-2008). The components of net periodic benefit cost (income) related to the non-contributory, defined benefit pension plan for the years ended December 31 are as follows: In thousands 2019 2018 Components of net periodic benefit cost (income): Service cost $ 696 $ 860 Interest cost 1,213 1,096 Expected return on plan assets (2,549 ) (2,770 ) Recognized net actuarial loss 850 515 Amortization of prior service cost — — Net Periodic Benefit Cost (Income) 210 (299 ) Net loss 224 2,365 Amortization of net loss (850 ) (515 ) Amortization of prior service cost — — Total recognized in other comprehensive (income) loss $ (626 ) $ 1,850 Total recognized in net periodic benefit cost (income) and other comprehensive (income) loss $ (416 ) $ 1,551 For the years ended December 31, 2019 and 2018 , the assumptions used to determine the benefit obligation are as follows: 2019 2018 Discount rate 3.20 % 4.10 % Rate of compensation increase 3.50 % 3.50 % For the years ended December 31, 2019 and 2018 , the assumptions used to determine the net periodic benefit cost (income) are as follows: 2019 2018 Discount rate 4.10 % 3.55 % Expected long-term rate of return on plan assets 6.75 % 6.75 % Rate of compensation increase 3.50 % 3.50 % The Corporation’s pension plan weighted-average assets’ allocations at December 31, 2019 and 2018 , are as follows: 2019 2018 Equity securities 45 % 63 % Debt securities 42 % 34 % Short-term fixed income — % — % Real estate 13 % 3 % 100 % 100 % The Corporation’s overall investment strategy is to achieve a mix of investments to meet the long-term rate of return assumption and near-term pension obligations with a diversification of assets types, fund strategies and fund managers. The mix of investments is adjusted periodically by retaining an advisory firm to recommend appropriate allocations after reviewing the Corporation’s risk tolerance on contribution levels, funded status and plan expense, and any applicable regulatory requirements. The weighted-average assets’ allocation in the above table represents the Corporation’s conclusion on the appropriate mix of investments. The specific investment vehicles are institutional separate accounts from a variety of fund managers which are regularly reviewed by the Corporation for acceptable performance. Equity securities included Corporation common stock in amounts of $2,854,000 , or 6% of total plan assets, and $2,882,000 , or 7% of total plan assets, at December 31, 2019 and 2018 , respectively. Fair value measurements at December 31, 2019 , are as follows: In thousands Total Level 1 Level 2 Level 3 Equity securities $ 20,098 $ 2,854 $ 17,244 $ — Debt securities 18,516 — 18,516 — Real estate 5,678 — 5,678 — Fair value measurements at December 31, 2018 , are as follows: In thousands Total Level 1 Level 2 Level 3 Equity securities $ 25,150 $ 2,882 $ 22,268 $ — Debt securities 13,376 — 13,376 — Real estate 1,154 — 1,154 — It has not yet been determined the amount that the Bank may contribute to the Plan in 2020 . The Corporation reduced the future benefit accruals for the defined benefit pension plan effective January 1, 2010, in order to manage total benefit expense. The new formula is the earned benefit as of December 31, 2009, plus 0.75% of a participant’s average monthly pay multiplied by years of benefit service earned on and after January 1, 2010, but not more than 25 years. The benefit formula percentage and maximum years of benefit service were both reduced. Effective April 1, 2012, no inactive or former participant in the Plan is eligible to again participate in the plan, and no employee hired after March 31, 2012, is eligible to participate in the Plan. As of the last annual census, ACNB Bank had a combined 348 active, vested terminated, and retired persons in the Plan. Based on current data and assumptions, the following benefit payments, which reflect expected future service, as appropriate, are: Years Ending In thousands 2020 $ 1,550 2021 1,670 2022 1,680 2023 1,800 2024 1,840 2025 - 2029 9,480 The Corporation’s banking subsidiary maintains a 401(k) plan for the benefit of eligible employees. Employees may contribute up to 100% of their compensation subject to certain limits based on federal tax laws. The Bank makes matching contributions equal to 100% of an employee’s compensation contributed to the plan which is not over 3% of an employee’s pay, plus 50% of an employee’s compensation contributed to the plan which is over 3% of their pay, but it not over 5% of an employee’s pay. Matching contributions vest immediately to the employee. Bank contributions to and expenses for the plan were $709,000 and $664,000 for 2019 and 2018 , respectively. RIG has a similar but separate 401(k) plan with the match of 6% for non-highly compensated employees and 3% match for highly compensated employees. RIG’s contributions to and expenses for the plan were $123,000 and $97,000 for 2019 and 2018 , respectively. The Corporation’s banking subsidiary maintains nonqualified compensation plans for selected senior officers. The estimated present value of future benefits is accrued over the period from the effective date of the agreements until the expected retirement dates of the individuals. The balance accrued for these plans included in other liabilities as of December 31, 2019 and 2018 , totaled $3,196,000 and $2,932,000 , respectively. The annual expense included in salaries and benefits expense totaled $493,000 and $463,000 during the years ended December 31, 2019 and 2018 , respectively. To fund the benefits under these plans, the Bank is the owner of single premium life insurance policies on participants in the nonqualified retirement plans.

STOCKHOLDERS' EQUITY AND REGULA

STOCKHOLDERS' EQUITY AND REGULATORY MATTERS	12 Months Ended
	Dec. 31, 2019
Broker-Dealer, Net Capital Requirement, SEC Regulation [Abstract]
STOCKHOLDERS' EQUITY AND REGULATORY MATTERS	STOCKHOLDERS’ EQUITY AND REGULATORY MATTERS In January 2011, the Corporation offered shareholders the opportunity to participate in the ACNB Corporation Dividend Reinvestment and Stock Purchase Plan. The plan provides registered holders of ACNB Corporation common stock with a convenient way to purchase additional shares of common stock by permitting participants in the plan to automatically reinvest cash dividends on all or a portion of the shares owned and to make quarterly voluntary cash payments under the terms of the plan. Participation in the plan is voluntary, and there are eligibility requirements to participate in the plan. During 2019 , 17,324 shares were issued under this plan with proceeds in the amount of $501,000 . During 2018 , 15,618 shares were issued under this plan with proceeds in the amount of $528,000 . Proceeds are used for general corporate purposes. The ACNB Corporation 2009 Restricted Stock Plan expired by its own terms after ten years on February 24, 2019. No further shares may be issued under this plan. Of the 200,000 shares of common stock authorized under this plan, 25,945 shares were issued. The remaining 174,055 shares were transferred to the ACNB Corporation 2018 Omnibus Stock Incentive Plan, which was approved and ratified on May 1, 2018. Under this plan awards shall not exceed, in the aggregate, 400,000 shares of common stock plus any shares that are authorized, but not issued, under the ACNB Corporation 2009 Restricted Stock Plan. The purpose of the plans were to provide employees and directors of the Bank who have responsibility for its growth with additional incentive by allowing them to acquire ownership in the Corporation and thereby encouraging them to contribute to the success of the Corporation. In 2019 and 2018 , 16,115 and 6,644 shares, respectively, were issued under these plans. The acquisition of New Windsor Bancorp, Inc. resulted in 938,360 new ACNB shares issued to the New Windsor Bancorp, Inc. shareholders valued at $28,620,000 in 2017. The Corporation and the Bank are subject to various regulatory capital requirements administered by the federal banking agencies. Failure to meet the minimum capital requirements can initiate certain mandatory and possibly additional discretionary actions by regulators that, if undertaken, could have a direct material effect on the Corporation’s consolidated financial statements. Under capital adequacy guidelines and the regulatory framework for prompt corrective action, the Corporation and the Bank must meet specific capital guidelines that involve quantitative measures of their assets, liabilities and certain off-balance sheet items as calculated under regulatory accounting practices. The capital amounts and classification are also subject to qualitative judgments by the regulators about components, risk weightings, and other factors. Quantitative measures established by regulation to ensure capital adequacy require the Corporation and the Bank to maintain minimum amounts and ratios (set forth below) of total and Tier 1 capital to average assets. The federal banking agencies issued final rules to implement the Basel III regulatory capital reforms and changes required by the Dodd-Frank Act. The phase-in period for community banking organizations began January 1, 2015, while larger institutions (generally those with assets of $250 billion or more) began compliance effective January 1, 2014. The final rules call for the following capital requirements: • a minimum ratio of common Tier 1 capital to risk-weighted assets of 4.5%; • a minimum ratio of Tier 1 capital to risk-weighted assets of 6.0%; • a minimum ratio of total capital to risk-weighted assets of 8.0%; and, • a minimum leverage ratio of 4.0%. In addition, the final rules establish a common equity Tier 1 capital conservation buffer of 2.5% of risk-weighted assets applicable to all banking organizations. If a banking organization fails to hold capital above the minimum capital ratios and the capital conservation buffer, it will be subject to certain restrictions on capital distributions and discretionary bonus payments. The 2.5% (after a 0.625% per year phase-in period) for the capital conservation and countercyclical capital buffers for all banking organizations began on January 1, 2016. The required capital conservation buffer was 2.5% at December 31, 2019 . Management believes, as of December 31, 2019 , that the Corporation and the Bank meet all capital adequacy requirements to which they are subject. As of December 31, 2019 , the most recent notification from the federal banking regulators categorized the Bank as “well capitalized” under the regulatory framework for prompt corrective action. There are no subsequent conditions or events that management believes have changed the Bank’s category. The actual and required capital amounts and ratios were as follows: Actual For Capital Adequacy Purposes To be Well Capitalized under Prompt Corrective Action Provisions Dollars in thousands Amount Ratio Amount (1) Ratio (1) Amount Ratio CORPORATION As of December 31, 2019 Tier 1 leverage ratio (to average assets) $ 176,403 10.19 % $ ≥69,239 ≥4.0% N/A N/A Common Tier 1 risk-based capital ratio (to risk-weighted assets) 176,403 14.50 ≥54,759 ≥4.5 N/A N/A Tier 1 risk-based capital ratio (to risk-weighted assets) 176,403 14.50 ≥73,012 ≥6.0 N/A N/A Total risk-based capital ratio (to risk-weighted assets) 190,319 15.64 ≥97,349 ≥8.0 N/A N/A As of December 31, 2018 Tier 1 leverage ratio (to average assets) $ 158,404 9.66 % $ ≥65,568 ≥4.0% N/A N/A Common Tier 1 risk-based capital ratio (to risk-weighted assets) 158,404 13.19 ≥54,026 ≥4.5 N/A N/A Tier 1 risk-based capital ratio (to risk-weighted assets) 158,404 13.19 ≥72,034 ≥6.0 N/A N/A Total risk-based capital ratio (to risk-weighted assets) 172,449 14.36 ≥96,046 ≥8.0 N/A N/A BANK As of December 31, 2019 Tier 1 leverage ratio (to average assets) $ 171,179 9.93 % $ ≥68,982 ≥4.0% $ ≥86,228 ≥5.0% Common Tier 1 risk-based capital ratio (to risk-weighted assets) 171,179 14.13 ≥54,514 ≥4.5 ≥78,742 ≥6.5 Tier 1 risk-based capital ratio (to risk-weighted assets) 171,179 14.13 ≥72,685 ≥6.0 ≥96,913 ≥8.0 Total risk-based capital ratio (to risk-weighted assets) 185,095 15.28 ≥96,913 ≥8.0 ≥121,142 ≥10.0 As of December 31, 2018 Tier 1 leverage ratio (to average assets) $ 154,215 9.44 % $ ≥65,348 ≥4.0% $ ≥81,686 ≥5.0% Common Tier 1 risk-based capital ratio (to risk-weighted assets) 154,215 12.89 ≥53,826 ≥4.5 ≥77,748 ≥6.5 Tier 1 risk-based capital ratio (to risk-weighted assets) 154,215 12.89 ≥71,768 ≥6.0 ≥95,690 ≥8.0 Total risk-based capital ratio (to risk-weighted assets) 168,260 14.07 ≥95,690 ≥8.0 ≥119,613 ≥10.0 (1) Amounts and ratios do not include capital conservation buffer.

FINANCIAL INSTRUMENTS WITH OFF-

FINANCIAL INSTRUMENTS WITH OFF-BALANCE SHEET RISK	12 Months Ended
	Dec. 31, 2019
Risks and Uncertainties [Abstract]
FINANCIAL INSTRUMENTS WITH OFF-BALANCE SHEET RISK	FINANCIAL INSTRUMENTS WITH OFF-BALANCE SHEET RISK The Corporation is a party to financial instruments with off-balance sheet risk in the normal course of business to meet the financing needs of its customers. These financial instruments consist primarily of commitments to extend credit (typically mortgages and commercial loans) and, to a lesser extent, standby letters of credit. These instruments involve, to varying degrees, elements of credit and interest rate risk in excess of the amount recognized on the consolidated balance sheet. The Corporation’s exposure to credit loss in the event of nonperformance by the other party to the financial instrument for commitments to extend credit and standby letters of credit is represented by the contractual amount of those instruments. The Corporation uses the same credit policies in making commitments and conditional obligations as it does for on balance sheet instruments. The Corporation does not anticipate any material losses from these commitments. Commitments to extend credit, including commitments to grant loans and unfunded commitments under lines of credit, are agreements to lend to a customer as long as there is no violation of any condition established in the contract. Commitments generally have fixed expiration dates or other termination clauses and may require payment of a fee. Since many of the commitments are expected to expire without being drawn upon, the total commitment amounts do not necessarily represent future cash requirements. The Corporation evaluates each customer’s creditworthiness on a case-by-case basis. The amount of collateral obtained, if deemed necessary by the Corporation upon extensions of credit, is based on management’s credit evaluation of the customer. Collateral held varies but may include accounts receivable, inventory, property and equipment and income-producing commercial properties. On loans secured by real estate, the Corporation generally requires loan to value ratios of no greater than 80% . Standby letters of credit are conditional commitments issued by the Corporation to guarantee the performance of a customer to a third party. Those guarantees are primarily issued to support public and private borrowing arrangements and similar transactions. The terms of the letters of credit vary and may have renewal features. The credit risk involved in issuing letters of credit is essentially the same as that involved in extending loans to customers. The Corporation generally holds collateral and/or personal guarantees supporting those commitments for which collateral is deemed necessary. Management believes that the proceeds obtained through a liquidation of such collateral and the enforcement of guarantees would be sufficient to cover the maximum potential amount of future payments required under the corresponding guarantees. The current amount of the liability as of December 31, 2019 and 2018 , for guarantees under standby letters of credit issued is not material. In 2018, ACNB Corporation executed a guaranty for a note related to a $1,500,000 commercial line of credit from a local bank, with normal terms and conditions for such a line, for Russell Insurance Group, Inc., the borrower and a wholly-owned subsidiary of ACNB Corporation. The commercial line of credit is for general working capital needs as they arise by the borrower. A net draw of $750,000 was taken on this commercial line of credit since its inception. The liability is recorded for the net drawn amount of this line, no further liability is recorded for the remaining line as to the guarantor’s obligation as the guarantor would have full recourse from all assets of its wholly-owned subsidiary. The Corporation has not been required to perform on any financial guarantees, and has not incurred any losses on its commitments, during the past three years. A summary of the Corporation’s commitments at December 31 were as follows: In thousands 2019 2018 Commitments to extend credit $ 319,681 $ 279,729 Standby letters of credit 6,584 3,909

CONTINGENCIES

CONTINGENCIES	12 Months Ended
	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
CONTINGENCIES	CONTINGENCIES The Corporation is subject to claims and lawsuits which arise primarily in the ordinary course of business. Based on information presently available and advice received from legal counsel representing the Corporation in connection with any such claims and lawsuits, it is the opinion of management that the disposition or ultimate determination of any such claims and lawsuits will not have a material adverse effect on the consolidated financial position, consolidated results of operations or liquidity of the Corporation.

ACNB CORPORATION (PARENT COMPAN

ACNB CORPORATION (PARENT COMPANY ONLY) FINANCIAL INFORMATION	12 Months Ended
	Dec. 31, 2019
Condensed Financial Information Disclosure [Abstract]
ACNB CORPORATION (PARENT COMPANY ONLY) FINANCIAL INFORMATION	ACNB CORPORATION (PARENT COMPANY ONLY) FINANCIAL INFORMATION STATEMENTS OF CONDITION December 31, In thousands 2019 2018 ASSETS Cash $ 6,828 $ 7,391 Investment in banking subsidiary 176,689 156,651 Investment in other subsidiaries 10,473 9,389 Investments in low-income housing partnerships — 240 Securities and other assets 1,558 1,271 Receivable from banking subsidiary 812 518 Total Assets $ 196,360 $ 175,460 LIABILITIES AND STOCKHOLDERS’ EQUITY Long-term debt $ 6,830 $ 7,300 Other liabilities 14 23 Stockholders’ equity 189,516 168,137 Total Liabilities and Stockholders’ Equity $ 196,360 $ 175,460 STATEMENTS OF INCOME AND COMPREHENSIVE INCOME Years Ended December 31, In thousands 2019 2018 Dividends from banking subsidiary $ 6,920 $ 6,261 Gain on sale of securities — 47 Other income 282 35 7,202 6,343 Expenses 1,739 1,421 5,463 4,922 Income tax benefit 501 547 5,964 5,469 Equity in undistributed earnings of subsidiaries 17,757 16,279 Net Income $ 23,721 $ 21,748 Comprehensive Income $ 27,085 $ 19,623 STATEMENTS OF CASH FLOWS Years Ended December 31, In thousands 2019 2018 CASH FLOWS FROM OPERATING ACTIVITIES Net income $ 23,721 $ 21,748 Equity in undistributed earnings of subsidiaries (17,757 ) (16,279 ) Increase in receivable from banking subsidiary (294 ) (400 ) Gain on sale of securities — 47 Other (57 ) 669 Net Cash Provided by Operating Activities 5,613 5,785 CASH FLOWS FROM INVESTING ACTIVITIES — — Net Cash Used in Investing Activities — — CASH FLOWS USED IN FINANCING ACTIVITIES Repayments on long-term debt (470 ) (2,300 ) Proceeds from issuance of common stock 1,214 727 Dividends paid (6,920 ) (6,261 ) Net Cash Used in Financing Activities (6,176 ) (7,834 ) Net Decrease in Cash and Cash Equivalents (563 ) (2,049 ) CASH AND CASH EQUIVALENTS — BEGINNING 7,391 9,440 CASH AND CASH EQUIVALENTS — ENDING $ 6,828 $ 7,391

GOODWILL AND OTHER INTANGIBLES

GOODWILL AND OTHER INTANGIBLES	12 Months Ended
	Dec. 31, 2019
Business Combinations [Abstract]
GOODWILL AND OTHER INTANGIBLE ASSETS	GOODWILL AND OTHER INTANGIBLES On January 5, 2005, ACNB Corporation completed its acquisition of Russell Insurance Group, Inc. (RIG) of Westminster, Maryland. The acquisition of RIG resulted in goodwill of approximately $6,308,000 . On July 1, 2017, ACNB completed its acquisition of New Windsor Bancorp Inc. (New Windsor) of Taneytown, Maryland. The acquisition of New Windsor resulted in goodwill of approximately $13,272,000 and generated $2,418,000 in core deposit intangibles. Combined goodwill included in the Corporation’s consolidated statement of condition is $19,580,000 . Goodwill, which has an indefinite useful life, is evaluated for impairment annually and is evaluated for impairment more frequently if events and circumstances indicate that the asset might be impaired. The Corporation did not identify any goodwill impairment on RIG or the Bank outstanding goodwill from its most recent testing. There are no impairment losses associated with goodwill as of December 31, 2019 and 2018 . Additionally, there are no accumulated impairment losses associated with goodwill as of December 31, 2019 and 2018 . No change occurred during the year with RIG’s goodwill, $6,308,000 , or the Bank’s goodwill of $13,272,000 . Goodwill represents the excess of the cost of an acquisition over the fair value of the net assets acquired. Other intangible assets represent purchased assets that lack physical substance but can be distinguished from goodwill because of contractual or other legal rights. Intangible assets that have finite lives, such as core deposit intangibles, customer relationship intangibles and renewal lists, are amortized over their estimated useful lives and subject to periodic impairment testing. Core deposit intangibles are primarily amortized over ten years using accelerated methods. Customer renewal lists are amortized over their estimated useful lives which range from eight to fifteen years . The carrying value and accumulated amortization of the intangible assets (RIG customer lists and New Windsor core deposit intangibles) are as follows: 2019 2018 Dollars in thousands Gross Carrying Amount Accumulated Amortization Gross Carrying Amount Accumulated Amortization RIG amortized intangible assets 9,890 6,869 9,250 6,623 New Windsor core deposit intangibles 2,418 1,012 2,418 638 $ 12,308 $ 7,881 $ 11,668 $ 7,261 Amortization expense was $621,000 and $745,000 for the years ended December 31, 2019 and 2018 , respectively. Amortization of the intangible assets for the five years subsequent to December 31, 2019 , is expected to be as follows: Years Ending In thousands 2020 $ 590 2021 546 2022 502 2023 458 2024 406 Thereafter 1,925

SEGMENT AND RELATED INFORMATION

SEGMENT AND RELATED INFORMATION	12 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
SEGMENT AND RELATED INFORMATION	SEGMENT AND RELATED INFORMATION The Corporation has two reporting segments, the Bank and RIG. RIG is managed separately from the banking segment, which includes the Bank and related financial services that the Corporation offers through its banking subsidiary. RIG offers a broad range of property and casualty, life and health insurance to both commercial and individual clients. Segment information for 2019 and 2018 is as follows: In thousands Banking Insurance Total 2019 Net interest income and other income from external customers $ 71,713 $ 5,874 $ 77,587 Income before income taxes 27,870 1,496 29,366 Total assets 1,707,653 12,600 1,720,253 Capital expenditures 1,367 57 1,424 2018 Net interest income and other income from external customers $ 67,654 $ 5,389 $ 73,043 Income before income taxes 25,515 1,205 26,720 Total assets 1,634,750 12,974 1,647,724 Capital expenditures 1,341 402 1,743

ACQUISITION

ACQUISITION	12 Months Ended
	Dec. 31, 2019
Business Combinations [Abstract]
ACQUISITION	ACQUISITION Effective January 11, 2020, ACNB Corporation (ACNB) completed the acquisition of Frederick County Bancorp, Inc. (FCBI) pursuant to the Agreement and Plan of Reorganization, dated as of July 1, 2019, by and among ACNB, ACNB South Acquisition Subsidiary, LLC (Acquisition Subsidiary), ACNB Bank, FCBI and Frederick County Bank (the Reorganization Agreement). At the effective time of the acquisition, FCBI merged with and into Acquisition Subsidiary with Acquisition Subsidiary surviving the merger. In addition, Frederick County Bank, a Maryland state-chartered bank and FCBI’s wholly-owned subsidiary, merged with and into ACNB Bank, a Pennsylvania state-chartered bank and trust company and ACNB’s wholly-owned subsidiary, with ACNB Bank as the surviving bank. Subject to the terms and conditions of the Reorganization Agreement at the effective time of the merger, each share of FCBI common stock was converted into the right to receive 0.9900 share of ACNB common stock. As a result of the merger, ACNB issued 1,590,547 shares of its common stock and cash in exchange for fractional shares based upon $36.43 , the determined market share price of ACNB common stock in accordance with the Reorganization Agreement. Effective January 11, 2020, in connection with the merger and pursuant to the terms of the Reorganization Agreement, one former FCBI director, Kimberly S. Chaney, was appointed as a Class 3 Director of ACNB’s Board of Directors. Ms. Chaney was also appointed as Director of ACNB Bank’s Board of Directors. With the combination of the two organizations, ACNB Corporation, on a consolidated basis, will have approximate total assets of $2.2 billion , total deposits of $1.8 billion and total loans of $1.6 billion . During the year ended December 31, 2019, merger expenses of $769,000 were incurred for this acquisition. The merger transaction will be accounted for using the acquisition method of accounting and, accordingly, assets acquired, liabilities assumed, and consideration exchanged will be recorded at estimated fair values on the acquisition date. Management is in the process of assessing the assets purchased and liabilities assumed in connection with the merger.

REVENUE RECOGNITION

REVENUE RECOGNITION	12 Months Ended
	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
REVENUE RECOGNITION	REVENUE RECOGNITION As disclosed in Note A, as of January 1, 2018, the Corporation adopted ASU 2014-09, Revenue from Contracts with Customers (Topic 606) , as well as subsequent ASUs that modified ASC 606. The Company has elected to apply the ASU and all related ASUs using the cumulative effect approach. The implementation of the guidance had no material impact on the measurement or recognition of revenue of prior periods. The Corporation generally fully satisfies its performance obligations on its contracts with customers as services are rendered and the transaction prices are typically fixed; charged either on a periodic basis or based on activity. Because performance obligations are satisfied as services are rendered and the transaction prices are fixed, there is little judgment involved in applying Topic 606 that significantly affects the determination of the amount and timing of revenue from contracts with customers. Additional disclosures related to the Corporation’s largest sources of noninterest income within the consolidated statements of income that are subject to ASC 606 are as follows: Income from fiduciary, investment management and brokerage activities - ACNB Bank’s Trust & Investment Services, under the umbrella of ACNB Wealth Management, provides a wide range of financial services, including trust services for individuals, businesses and retirement funds. Other services include, but are not limited to, those related to testamentary trusts, life insurance trusts, charitable remainder trusts, guardianships, power of attorney, custodial accounts and investment management and advisor accounts. In addition, ACNB’s Wealth Management Department offers retail brokerage-services through a third party provider. Wealth Management clients are located primarily within the Corporation’s geographic markets. Assets held by the Corporation’s Wealth Management Department, including trust and retail brokerage, in an agency, fiduciary or retail brokerage capacity for its customers are excluded from the consolidated financial statement since they do not constitute assets of the Corporation. Assets held by the Wealth Management Department amounted to $389,000,000 and $342,000,000 at December 31, 2019 and 2018 , respectively. Income from fiduciary, investment management and brokerage activities are included in other income. The majority of trust services revenue is earned and collected monthly, with the amount determined based on the investment funds in each trust multiplied by a fee schedule for type of trust. Each trust has one integrated set of performance obligations so no allocation is required. The performance obligation is met by performing the identified fiduciary service. Successful performance is confirmed by ongoing internal and regulatory control, measurement is by valuing the trust assets at a monthly date to which a fee schedule is applied. Wealth management fees are contractually agreed with each customer, and fee levels vary based mainly on the size of assets under management. The costs of acquiring trust customers are incremental and recognized within noninterest expense in the consolidated statements of income. Service charges on deposit accounts - Deposits are included as liabilities in the consolidated balance sheets. Service charges on deposit accounts include: overdraft fees, which are charged when customers overdraw their accounts beyond available funds; automated teller machine (ATM) fees charged for withdrawals by deposit customers from other financial institutions’ ATMs; and a variety of other monthly or transactional fees for services provided to retail and business customers, mainly associated with checking accounts. All deposit liabilities are considered to have one-day terms and therefore related fees are recognized in income at the time when the services are provided to the customers. Incremental costs of obtaining deposit contracts are not significant and are recognized as expense when incurred within noninterest expense in the consolidated statements of income. Interchange revenue from debit card transactions - The Corporation issues debit cards to consumer and business customers with checking, savings or money market deposit accounts. Debit card and ATM transactions are processed via electronic systems that involve several parties. The Corporation’s debit card and ATM transaction processing is executed via contractual arrangements with payment processing networks, a processor and a settlement bank. As described above, all deposit liabilities are considered to have one-day terms and therefore interchange revenue from customers’ use of their debit cards to initiate transactions are recognized in income at the time when the services are provided and related fees received in the Corporation’s deposit account with the settlement bank. Incremental costs associated with ATM and interchange processing are recognized as expense when incurred within noninterest expense in the consolidated statements of income.

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policy)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Nature of Operations	Nature of Operations ACNB Corporation (the Corporation or ACNB), headquartered in Gettysburg, Pennsylvania, provides banking, insurance, and financial services to businesses and consumers through its wholly-owned subsidiaries, ACNB Bank (Bank) and Russell Insurance Group, Inc. (RIG). The Bank engages in full-service commercial and consumer banking and wealth management services, including trust and retail brokerage, through its twenty-two community banking office locations in Adams, Cumberland, Franklin, and York Counties, Pennsylvania. There are also loan production offices situated in Lancaster and York, Pennsylvania, and Hunt Valley, Maryland. RIG is a full-service insurance agency based in Westminster, Maryland, with additional locations in Germantown and Jarrettsville, Maryland. The agency offers a broad range of property and casualty and group life and health insurance to both individual and commercial clients. On July 1, 2017, ACNB completed its acquisition of New Windsor Bancorp, Inc. (New Windsor) of Taneytown, Maryland. At the effective time of the acquisition, New Windsor merged with and into a wholly-owned subsidiary of ACNB, immediately followed by the merger of New Windsor State Bank (NWSB) with and into ACNB Bank. ACNB Bank now operates in the Maryland market as “NWSB Bank, A Division of ACNB Bank” and serves its marketplace with banking and wealth management services via a network of seven community banking offices located in Carroll County, Maryland. Effective January 11, 2020, ACNB completed its acquisition of Frederick County Bancorp, Inc. (FCBI) and its wholly-owned subsidiary, Frederick County Bank, headquartered in Frederick, Maryland. FCBI was merged with and into a wholly-owned subsidiary of ACNB Corporation immediately followed by the merger of Frederick County Bank with and into ACNB Bank. ACNB Bank will operate in the Frederick County, Maryland, market as “FCB Bank, A Division of ACNB Bank”. Under the terms of the Reorganization Agreement, FCBI stockholders received 0.9900 share of ACNB Corporation common stock for each share of FCBI common stock that they owned as of the closing date. As a result, ACNB Corporation issued 1,590,547 shares of its common stock and cash in exchange for fractional shares based upon $36.43 , the determined market share price of ACNB Corporation common stock in accordance with the Reorganization Agreement. One director from FCBI will join the boards of directors of ACNB and ACNB Bank, respectively. With the combination of the two organizations, ACNB Corporation, on a consolidated basis, has approximately $2.2 billion in assets, $1.8 billion in deposits, and $1.6 billion in loans with 34 community banking offices and three loan offices located in the counties of Adams, Cumberland, Franklin, Lancaster and York in Pennsylvania, and the counties of Baltimore, Carroll and Frederick in Maryland. Further discussion of the risk factors involved with the merger of FCBI into the Corporation can be found in Part I, Item 1A–Risk Factors. The Corporation’s primary sources of revenue are interest income on loans and investment securities and fee income on its products and services. Expenses consist of interest expense on deposits and borrowed funds, provisions for loan losses, and other operating expenses.
Basis of Financial Statements	Basis of Financial Statements The consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (US GAAP) and include the accounts of the Corporation and its wholly-owned subsidiaries. All significant intercompany transactions have been eliminated. Assets held by the Corporation’s Wealth Management Department, including trust and retail brokerage, in an agency, fiduciary or retail brokerage capacity for its customers are excluded from the consolidated financial statements since they do not constitute assets of the Corporation. Assets held by the Wealth Management Department amounted to $389,000,000 and $342,000,000 at December 31, 2019 and 2018 , respectively. Income from fiduciary, investment management and brokerage activities are included in other income. The Corporation has evaluated events and transactions occurring subsequent to the balance sheet date of December 31, 2019 , for items that should potentially be recognized or disclosed in the consolidated financial statements. The evaluation was conducted through the date these consolidated financial statements were issued.
Use of Estimates	Use of Estimates Financial statements prepared in accordance with GAAP require management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingencies at the date of the consolidated financial statements, and revenues and expenses during the reporting period. Actual results could differ from these estimates. Material estimates that are particularly susceptible to significant change in the near term relate to the determination of the allowance for loan losses, the determination of other than temporary impairment on securities, and the potential impairment of goodwill.
Significant Group Concentrations of Credit Risk	Significant Group Concentrations of Credit Risk Most of the Corporation’s activities are with customers located within southcentral Pennsylvania and northern Maryland. Note C discusses the types of securities in which the Corporation invests. Note D discusses the types of lending in which the Corporation engages. Included in commercial real estate loans are loans made to lessors of non-residential dwellings that total $297,654,000 , or 23.4% , of total loans at December 31, 2019 . These borrowers are geographically disbursed throughout ACNB’s marketplace and are leasing commercial properties to a varied group of tenants including medical offices, retail space and recreational facilities. Because of the varied nature of the tenants in aggregate, management believes that these loans do not present any greater risk than commercial loans in general.
Cash and Cash Equivalents	Cash and Cash Equivalents For purposes of the consolidated statements of cash flows, cash and cash equivalents include cash on hand, balances due from banks, and federal funds sold, all of which mature within 90 days.
Securities	Securities Debt securities that management has the positive intent and ability to hold to maturity are classified as “held to maturity” and recorded at amortized cost. Debt securities not classified as held to maturity or trading are classified as “available for sale” and recorded at fair value, with unrealized gains and losses excluded from earnings and reported, net of tax, in other comprehensive income (loss). As of January 1, 2018, equity securities with readily determined fair values are recorded at fair value with changes in fair value recognized in net income. Prior to 2018, fair value changes were reported, net of tax, in other comprehensive income (loss). Purchase premiums and discounts are recognized in interest income using the interest method over the terms of the securities. Declines in the fair value of held to maturity and available for sale securities below their cost that are deemed to be other than temporary are reflected in earnings as realized losses. In estimating other-than-temporary impairment losses on debt securities, management considers (1) whether management intends to sell the security, or (2) if it is more likely than not that management will be required to sell the security before recovery, or (3) if management does not expect to recover the entire amortized cost basis. In assessing potential other-than-temporary impairment for equity securities, consideration is given to management’s intention and ability to hold the securities until recovery of unrealized losses. Gains and losses on the sale of securities are recorded on the trade date and are determined using the specific identification method.
Loans Held for Sale	Loans Held for Sale Loans originated and intended for sale in the secondary market are carried at the lower of aggregate cost or fair value, as determined by aggregate outstanding commitments from investors or current investor yield requirements. Net unrealized losses are recognized through a valuation allowance by charges to income. Mortgage loans held for sale are sold with the mortgage servicing rights released to another financial institution through a correspondent relationship. The correspondent financial institution absorbs all of the risk related to rate lock commitments. Gains or losses on sales of mortgage loans are recognized based on the difference between the selling price and the carrying value of the related mortgage loans sold.
Loans	Loans The Corporation grants commercial, residential, and consumer loans to customers. A substantial portion of the loan portfolio is represented by mortgage loans throughout southcentral Pennsylvania and northern Maryland. The ability of the Corporation’s debtors to honor their contracts is dependent upon the real estate values and general economic conditions in this area. Loans that management has the intent and ability to hold for the foreseeable future or until maturity or pay-off generally are reported at their outstanding unpaid principal balances adjusted for charge-offs, the allowance for loan losses, and any deferred fees or costs on originated loans. Interest income is accrued on the unpaid principal balance. Loan origination fees, net of certain direct origination costs, are deferred and recognized as an adjustment of the related loan yield using the interest method. The loans receivable portfolio is segmented into commercial, residential mortgage, home equity lines of credit, and consumer loans. Commercial loans consist of the following classes: commercial and industrial, commercial real estate, and commercial real estate construction. The accrual of interest on residential mortgage and commercial loans is discontinued at the time the loan is 90 days past due unless the credit is well-secured and in process of collection. Consumer loans (consisting of home equity lines of credit and consumer loan classes) are typically charged off no later than 120 days past due. Past due status is based on the contractual terms of the loan. In all cases, loans are placed on nonaccrual or charged off at an earlier date if collection of principal or interest is considered doubtful. All interest accrued, but not collected, for loans that are placed on nonaccrual or charged off is reversed against interest income. The interest on these loans is accounted for on the cash-basis or cost-recovery method, until qualifying for return to accrual status. Loans are returned to accrual status when all the principal and interest amounts contractually due are brought current and future payments are reasonably assured.
Allowance for Credit Losses	Allowance for Credit Losses The allowance for credit losses consists of the allowance for loan losses and the reserve for unfunded lending commitments. The allowance for loan losses (the “allowance”) is established as losses are estimated to occur through a provision for loan losses charged to earnings. Loan losses are charged against the allowance when management believes the uncollectibility of a loan balance is confirmed. Subsequent recoveries, if any, are credited to the allowance. The reserve for unfunded lending commitments represents management’s estimate of losses inherent in its unfunded loan commitments and is recorded in other liabilities on the consolidated statement of condition. The amount of the reserve for unfunded lending commitments is not material to the consolidated financial statements. The allowance for loan losses is evaluated on a regular basis by management and is based upon management’s periodic review of the collectibility of the loans in light of historical experience, the nature and volume of the loan portfolio, adverse situations that may affect the borrower’s ability to repay, estimated value of any underlying collateral, and prevailing economic conditions. This evaluation is inherently subjective as it requires estimates that are susceptible to significant revision as more information becomes available. The allowance consists of specific, general and unallocated components. The specific component relates to loans that are classified as either doubtful, substandard, or special mention. For such loans that are also classified as impaired, an allowance is established when the discounted cash flows (or collateral value or observable market price) of the impaired loan is lower than the carrying value of that loan. The general component covers pools of loans by loan class including commercial loans not considered impaired, as well as smaller balance homogeneous loans, such as residential real estate, home equity, and other consumer loans. These pools of loans are evaluated for loss exposure based upon historical loss rates for each of these categories of loans, adjusted for qualitative risk factors. These qualitative risk factors include: • lending policies and procedures, including underwriting standards and collection, charge-off and recovery practices; • national, regional and local economic and business conditions, as well as the condition of various market segments, including the impact on the value of underlying collateral for collateral dependent loans; • the nature and volume of the portfolio and terms of loans; • the experience, ability and depth of lending management and staff; • the volume and severity of past due, classified and nonaccrual loans, as well as other loan modifications; and, • the existence and effect of any concentrations of credit and changes in the level of such concentrations. Each factor is assigned a value to reflect improving, stable or declining conditions based on management’s best judgment using relevant information available at the time of the evaluation. Adjustments to the factors are supported through documentation of changes in conditions in a narrative accompanying the allowance for loan loss calculation. The unallocated component of the allowance is maintained to cover uncertainties that could affect management’s estimate of probable losses. The unallocated component of the allowance reflects the margin of imprecision inherent in the underlying assumptions used in the methodologies for estimating specific and general losses in the portfolio. It covers risks that are inherently difficult to quantify including, but not limited to, collateral risk, information risk, and historical charge-off risk. A loan is considered impaired when, based on current information and events, it is probable that the Corporation will be unable to collect the scheduled payments of principal and/or interest when due according to the contractual terms of the loan agreement. Factors considered by management in determining impairment include payment status, collateral value, and the probability of collecting scheduled principal and/or interest payments when due. Loans that experience insignificant payment delays and payment shortfalls generally are not classified as impaired. Management determines the significance of payment delays and payment shortfalls on a case-by-case basis, taking into consideration all of the circumstances surrounding the loan and the borrower, including the length of the delay, the reasons for the delay, the borrower’s prior payment record, and the amount of the shortfall in relation to the principal and interest owed. Impairment is measured on a loan by loan basis for commercial and commercial construction loans by either the present value of expected future cash flows discounted at the loan’s effective interest rate, the loan’s obtainable market price, or the fair value of the collateral if the loan is collateral dependent. A specific allocation within the allowance for loan losses is established for an impaired loan if its carrying value exceeds its estimated fair value. The estimated fair values of the Corporation’s impaired loans are measured based on the estimated fair value of the loan’s collateral or the discounted cash flows method. It is the policy of the Corporation to order an updated valuation on all real estate secured loans when the loan becomes 90 days past due and there has not been an updated valuation completed within the previous 12 months . In addition, the Corporation orders third-party valuations on all impaired real estate collateralized loans within 30 days of the loan being classified as impaired. Until the valuations are completed, the Corporation utilizes the most recent independent third-party real estate valuation to estimate the need for a specific allocation to be assigned to the loan. These existing valuations are discounted downward to account for such things as the age of the existing collateral valuation, change in the condition of the real estate, change in local market and economic conditions, and other specific factors involving the collateral. Once the updated valuation is completed, the collateral value is updated accordingly. For commercial and industrial loans secured by non-real estate collateral, such as accounts receivable, inventory and equipment, estimated fair values are determined based on the borrower’s financial statements, inventory reports, accounts receivable aging reports, equipment appraisals, or invoices. Indications of value from these sources are generally discounted based on the age of the financial information or the quality of the assets. The Corporation actively monitors the values of collateral as well as the age of the valuation of impaired loans. The Corporation orders valuations at least every 18 months , or more frequently if management believes that there is an indication that the fair value has declined. For impaired loans secured by collateral other than real estate, the Corporation considers the net book value of the collateral, as recorded in the most recent financial statements of the borrower, and determines fair value based on estimates made by management. Large groups of smaller balance homogeneous loans are collectively evaluated for impairment. Accordingly, the Corporation does not separately identify individual consumer and residential loans for impairment disclosures, unless such loans are the subject of a troubled debt restructure. Loans whose terms are modified are classified as troubled debt restructured loans if the Corporation grants such borrowers concessions that it would not otherwise consider and it is deemed that those borrowers are experiencing financial difficulty. Concessions granted under a troubled debt restructuring generally involve a temporary reduction in interest rate, a below market interest rate given the risk associated with the loan, or an extension of a loan’s stated maturity date. Nonaccrual troubled debt restructurings may be restored to accrual status if principal and interest payments, under the modified terms, are current for a sustained period of time and, based on a well-documented credit evaluation of the borrower’s financial condition, there is reasonable assurance of repayment. Loans classified as troubled debt restructurings are generally designated as impaired. The allowance calculation methodology includes further segregation of loan classes into credit quality rating categories. The borrower’s overall financial condition, repayment sources, guarantors, and value of collateral, if appropriate, are generally evaluated annually for commercial loans or when credit deficiencies arise, such as delinquent loan payments. Credit quality risk ratings include regulatory classifications of special mention, substandard, doubtful and loss. Loans classified special mention have potential weaknesses that deserve management’s close attention. If uncorrected, the potential weaknesses may result in deterioration of the repayment prospects. Loans classified substandard have a well-defined weakness or weaknesses that jeopardize the liquidation of the debt. They include loans that are inadequately protected by the current sound net worth and paying capacity of the obligor or of the collateral pledged, if any. Loans classified doubtful have all the weaknesses inherent in loans classified substandard with the added characteristic that collection or liquidation in full, on the basis of current conditions and facts, is highly improbable. Loans classified as a loss are considered uncollectible and are charged to the allowance for loan losses. Loans not classified are rated pass. In addition, federal and state regulatory agencies, as an integral part of their examination process, periodically review the Corporation’s allowance for loan losses and may require the Corporation to recognize additions to the allowance based on their judgments about information available to them at the time of their examination, which may not be currently available to management. Based on management’s comprehensive analysis of the loan portfolio and economic conditions, management believes the current level of the allowance for loan losses is adequate. Commercial and Industrial Lending — The Corporation originates commercial and industrial loans primarily to businesses located in its primary market area and surrounding areas. These loans are used for various business purposes which include short-term loans and lines of credit to finance machinery and equipment purchases, inventory, and accounts receivable. Generally, the maximum term for loans extended on machinery and equipment is based on the projected useful life of such machinery and equipment. Most business lines of credit are written on demand and may be renewed annually. Commercial and industrial loans are generally secured with short-term assets; however, in many cases, additional collateral such as real estate is provided as additional security for the loan. Loan-to-value maximum values have been established by the Corporation and are specific to the type of collateral. Collateral values may be determined using invoices, inventory reports, accounts receivable aging reports, collateral appraisals, etc. In underwriting commercial and industrial loans, an analysis is performed to evaluate the borrower’s character and capacity to repay the loan, the adequacy of the borrower’s capital and collateral, as well as the conditions affecting the borrower. Evaluation of the borrower’s past, present and future cash flows is also an important aspect of the Corporation’s analysis. Commercial loans generally present a higher level of risk than other types of loans due primarily to the effect of general economic conditions. Commercial Real Estate Lending — The Corporation engages in commercial real estate lending in its primary market area and surrounding areas. The Corporation’s commercial loan portfolio is secured primarily by commercial retail space, office buildings, and hotels. Generally, commercial real estate loans have terms that do not exceed 20 years , have loan-to-value ratios of up to 80% of the appraised value of the property, and are typically secured by personal guarantees of the borrowers. In underwriting these loans, the Corporation performs a thorough analysis of the financial condition of the borrower, the borrower’s credit history, and the reliability and predictability of the cash flow generated by the property securing the loan. Appraisals on properties securing commercial real estate loans originated by the Corporation are performed by independent appraisers. Commercial real estate loans generally present a higher level of risk than other types of loans due primarily to the effect of general economic conditions and the complexities involved in valuing the underlying collateral. Commercial Real Estate Construction Lending — The Corporation engages in commercial real estate construction lending in its primary market area and surrounding areas. The Corporation’s commercial real estate construction lending consists of commercial and residential site development loans, as well as commercial building construction and residential housing construction loans. The Corporation’s commercial real estate construction loans are generally secured with the subject property. Terms of construction loans depend on the specifics of the project, such as estimated absorption rates, estimated time to complete, etc. In underwriting commercial real estate construction loans, the Corporation performs a thorough analysis of the financial condition of the borrower, the borrower’s credit history, and the reliability and predictability of the cash flow generated by the project using feasibility studies, market data, etc. Appraisals on properties securing commercial real estate construction loans originated by the Corporation are performed by independent appraisers. Commercial real estate construction loans generally present a higher level of risk than other types of loans due primarily to the effect of general economic conditions and the uncertainties surrounding total construction costs. Residential Mortgage Lending — One-to-four family residential mortgage loan originations, including home equity closed-end loans, are generated by the Corporation’s marketing efforts, its present customers, walk-in customers, and referrals. These loans originate primarily within the Corporation’s market area or with customers primarily from the market area. The Corporation offers fixed-rate and adjustable-rate mortgage loans with terms up to a maximum of 30 years for both permanent structures and those under construction. The Corporation’s one-to-four family residential mortgage originations are secured primarily by properties located in its primary market area and surrounding areas. The majority of the Corporation’s residential mortgage loans originate with a loan-to-value of 80% or less. Loans in excess of 80% are required to have private mortgage insurance. In underwriting one-to-four family residential real estate loans, the Corporation evaluates both the borrower’s financial ability to repay the loan as agreed and the value of the property securing the loan. Properties securing real estate loans made by the Corporation are appraised by independent appraisers. The Corporation generally requires borrowers to obtain an attorney’s title opinion or title insurance, as well as fire and property insurance (including flood insurance, if necessary) in an amount not less than the amount of the loan. The Corporation has not engaged in subprime residential mortgage originations. Residential mortgage loans are subject to risk due primarily to general economic conditions, as well as a continued weak housing market. Home Equity Lines of Credit Lending — The Corporation originates home equity lines of credit primarily within the Corporation’s market area or with customers primarily from the market area. Home equity lines of credit are generated by the Corporation’s marketing efforts, its present customers, walk-in customers, and referrals. Home equity lines of credit are secured by the borrower’s primary residence with a maximum loan-to-value of 90% and a maximum term of 20 years . In underwriting home equity lines of credit, the Corporation evaluates both the value of the property securing the loan and the borrower’s financial ability to repay the loan as agreed. The ability to repay is determined by the borrower’s employment history, current financial condition, and credit background. Home equity lines of credit generally present a moderate level of risk due primarily to general economic conditions, as well as a continued weak housing market. Junior liens inherently have more credit risk by virtue of the fact that another financial institution may have a higher security position in the case of foreclosure liquidation of collateral to extinguish the debt. Generally, foreclosure actions could become more prevalent if the real estate market continues to be weak and property values deteriorate. Consumer Lending — The Corporation offers a variety of secured and unsecured consumer loans, including those for vehicles and mobile homes and loans secured by savings deposits. These loans originate primarily within the Corporation’s market area or with customers primarily from the market area. Consumer loan terms vary according to the type and value of collateral and the creditworthiness of the borrower. In underwriting consumer loans, a thorough analysis of the borrower’s financial ability to repay the loan as agreed is performed. The ability to repay is determined by the borrower’s employment history, current financial condition, and credit background. Consumer loans may entail greater credit risk than residential mortgage loans or home equity lines of credit, particularly in the case of consumer loans which are unsecured or are secured by rapidly depreciable assets such as automobiles or recreational equipment. In such cases, any repossessed collateral for a defaulted consumer loan may not provide an adequate source of repayment of the outstanding loan balance as a result of the greater likelihood of damage, loss or depreciation. In addition, consumer loan collections are dependent on the borrower’s continuing financial stability, and thus are more likely to be affected by adverse personal circumstances. Furthermore, the application of various federal and state laws, including bankruptcy and insolvency laws, may limit the amount which can be recovered on such loans.
Acquired Loans	Acquired Loans Acquired Loans (impaired and non-impaired) are initially recorded at their acquisition-date fair values using Level 3 inputs. Fair values are based on a discounted cash flow methodology that involves assumptions and judgments as to credit risk, expected lifetime losses, environmental factors, collateral values, discount rates, expected payments and expected prepayments. Specifically, the Corporation has prepared three separate loan fair value adjustments that it believed a market participant might employ in estimating the entire fair value adjustment necessary under ASC 820-10 for the acquired loan portfolio. The three-separate fair valuation methodology employed are: 1) an interest rate loan fair value adjustment, 2) a general credit fair value adjustment, and 3) a specific credit fair value adjustment for purchased credit impaired loans subject to ASC 310-30 procedures. The carryover of allowance for loan losses related to acquired loans is prohibited as any credit losses in the loans are included in the determination of the fair value of the loans at the acquisition date. The allowance for loan losses on acquired loans reflects only those losses incurred after acquisition and represents the present value of cash flows expected at acquisition that is no longer expected to be collected. Acquired loans are marked to fair value on the date of acquisition. In conjunction with the quarterly evaluation of the adequacy of the allowance for loan losses, the Corporation performs an analysis on acquired loans to determine whether or not there has been subsequent deterioration in relation to those loans. If deterioration has occurred, the Corporation will include these loans in the calculation of the allowance for loan losses after the initial valuation, and provide accordingly. Upon acquisition, in accordance with US GAAP, the Corporation has individually determined whether each acquired loan is within the scope of ASC 310-30. The Corporation’s senior lending management reviewed the accounting seller’s loan portfolio on a loan by loan basis to determine if any loans met the two-part definition of an impaired loan as defined by ASC 310-30: 1) Credit deterioration on the loan from its inception until the acquisition date, and 2) It is probable that not all of the contractual cash flows will be collected on the loan. Acquired ASC 310-20 loans, which are loans that did not meet the criteria above, were pooled into groups of similar loans based on various factors including borrower type, loan purpose, and collateral type. For these pools, the Corporation used certain loan information, including outstanding principal balance, estimated expected losses, weighted average maturity, weighted average margin, and weighted average interest rate along with estimated prepayment rates, expected lifetime losses, environment factors to estimate the expected cash flow for each loan pool. With regards to ASC 310-30 loans, for external disclosure purposes, the aggregate contractual cash flows less the aggregate expected cash flows resulted in a credit related non-accretable yield amount. The aggregate expected cash flows less the acquisition date fair value resulted in an accretable yield amount. The accretable yield reflects the contractual cash flows management expects to collect above the loan’s acquisition date fair value and will be recognized over the life of the loan on a level-yield basis as a component of interest income. Over the life of the acquired ASC 310-30 loan, the Corporation continues to estimate cash flows expected to be collected. Decreases in expected cash flows, other than from prepayments or rate adjustments, are recognized as impairments through a charge to the provision for credit losses resulting in an increase in the allowance for credit losses. Subsequent improvements in cash flows result in first, reversal of existing valuation allowances recognized subsequent to acquisition, if any, and next, an increase in the amount of accretable yield to be subsequently recognized on a prospective basis over the loan’s remaining life. Acquired ASC 310-30 loans that met the criteria for non-accrual of interest prior to acquisition are considered performing upon acquisition, regardless of whether the customer is contractually delinquent, if we can reasonably estimate the timing and amount of expected cash flows on such loans. Accordingly, we do not consider acquired contractually delinquent loans to be non-accruing and continue to recognize interest income on these loans using the accretion model. For loans acquired without evidence of credit quality deterioration, ACNB prepared the interest rate loan fair value and credit fair value adjustments. Loans were grouped into homogeneous pools by characteristics such as loan type, term, collateral, and rate. Market rates for similar loans were obtained from various internal and external data sources and reviewed by management for reasonableness. The average of these rates was used as the fair value interest rate a market participant would utilize. A present value approach was utilized to calculate the interest rate fair value discount of $731,000 . Additionally, for loans acquired without credit quality deterioration, a credit fair value adjustment was calculated using a two-part credit fair value analysis: 1) expected lifetime credit migration losses; and 2) estimated fair value adjustment for certain qualitative factors. The expected lifetime losses were calculated using historical losses observed at the Bank, NWSB and peer banks. ACNB also estimated an environmental factor to apply to each loan type. The environmental factor represents potential discount which may arise due to general credit and economic factors. A credit fair value discount of $4.5 million was determined. Both the interest rate and credit fair value adjustments relate to loans acquired with evidence of credit quality deterioration will be substantially recognized as interest income on a level yield amortization method over the expected life of the loans.
Premises and Equipment	Premises and Equipment Land is carried at cost. Buildings, furniture, fixtures, equipment and leasehold improvements are carried at cost, less accumulated depreciation. Depreciation is computed principally by the straight-line method over the assets’ estimated useful lives. Normally, a buildings useful life is 40 years , except for building remodels and additions, which are depreciated over fifteen years . Bank equipment, including furniture and fixtures, is normally depreciated over five - fifteen years depending upon the nature of the purchase. Maintenance and normal repairs are charged to expense when incurred while major additions and improvements are capitalized. Gains and losses on disposals are reflected in current operations. Amortization of leasehold improvements is computed by straight line over the shorter of the assets’ useful life or the related lease term.
Restricted Investment in Bank Stocks	Restricted Investment in Bank Stocks Restricted investment in bank stocks, which represents required investments in the common stock of correspondent banks, is carried at cost as of December 31, 2019 and 2018 , and consists of common stock in the Atlantic Central Bankers Bank, Maryland Financial Bank, Community Bankers Bank and Federal Home Loan Bank (FHLB). Management evaluates the restricted investment in bank stocks for impairment in accordance with Accounting Standard Codification (ASC) Topic 942, Financial Services—Depository and Lending. Management’s determination of whether these investments are impaired is based on their assessment of the ultimate recoverability of their cost rather than by recognizing temporary declines in value. The determination of whether a decline affects the ultimate recoverability of their cost is influenced by criteria such as (1) the significance of the decline in net assets of the correspondent bank as compared to the capital stock amount for the correspondent bank and the length of time this situation has persisted, (2) commitments by the correspondent bank to make payments required by law or regulation and the level of such payments in relation to the operating performance of the correspondent bank, (3) the impact of legislative and regulatory changes on institutions and, accordingly, on the customer base of the correspondent bank, and (4) the liquidity position of the correspondent bank. Management believes no impairment charge was necessary related to the restricted investment in bank stocks during 2019 or 2018 . However, security impairment analysis is completed quarterly, and the determination that no impairment has occurred during those years is no assurance that impairment may not occur in future periods.
Bank-Owned Life Insurance	Bank-Owned Life Insurance The Corporation’s banking subsidiary maintains nonqualified compensation plans for selected senior officers. To fund the benefits under these plans, the Bank is the owner of single premium life insurance policies on participants in the nonqualified retirement plans. Investment in bank-owned life insurance policies was used to finance the nonqualified compensation plans and provide tax-exempt income to the Corporation. ASC Topic 715, Compensation—Retirement Benefits , requires a liability to be recorded during the service period when a split-dollar life insurance agreement continues after participants’ employment or retirement. The required accrued liability is based on either the post-employment benefit cost for continuing life insurance or based on the future death benefit depending on the contractual terms of the underlying agreement. The Corporation’s liability is based on the post-employment benefit cost for continuing life insurance. The Corporation incurred approximately $161,000 and $95,000 of expense in 2019 and 2018 , respectively, related to these benefits.
Investments in Low-Income Housing Partnerships	Investments in Low-Income Housing Partnerships The Corporation’s investments in low-income housing partnerships are accounted for using the “equity method” prescribed by ASC Topic 323, Investments — Equity Method . In accordance with ASC Topic 740, Income Taxes , tax credits are recognized as they become available. Any residual loss is amortized as the tax credits are received.
Goodwill and Intangible Assets	Goodwill and Intangible Assets The Corporation accounts for its acquisitions using the acquisition accounting method required by ASC Topic 805, Business Combinations. Acquisition accounting requires the total purchase price to be allocated to the estimated fair values of assets and liabilities acquired, including certain intangible assets that must be recognized. Generally, this results in a residual amount in excess of the net fair values, which is recorded as goodwill. ASC Topic 350, Intangibles—Goodwill and Other, requires that goodwill is not amortized to expense, but rather that it be assessed or tested for impairment at least annually. If certain events occur which might indicate goodwill has been impaired, the goodwill is tested for impairment when such events occur. Impairment write-downs are charged to results of operations in the period in which the impairment is determined. The Corporation did not identify any impairment on RIG’s outstanding goodwill from its most recent testing, which was performed as of October 1, 2019 . The Corporation did not identify any impairment on the Bank’s outstanding goodwill from its most recent qualitative assessment, which was completed as of December 31, 2019 . If certain events occur which might indicate goodwill has been impaired, the goodwill is tested for impairment when such events occur. Other acquired intangible assets that have finite lives, such as core deposit intangibles, customer relationship intangibles and renewal lists, are amortized over their estimated useful lives and subject to periodic impairment testing. Core deposit intangibles are primarily amortized over ten years using accelerated methods. Customer renewal lists are amortized using the straight line method over their estimated useful lives which range from eight to fifteen years .
Foreclosed Assets	Foreclosed Assets Assets acquired through, or in lieu of, loan foreclosure are held for sale and are initially recorded at fair value, less costs to sell at the date of foreclosure, establishing a new cost basis. Subsequent to foreclosure, valuations are periodically performed by management and the assets are adjusted to the fair value, less costs to sell as necessary. Revenue and expenses from operations and changes in the valuation allowance are included in net expenses from foreclosed assets.
Income Taxes	Income Taxes The Corporation accounts for income taxes in accordance with income tax accounting guidance ASC Topic 740, Income Taxes . Current income tax accounting guidance results in two components of income tax expense: current and deferred. Current income tax expense reflects taxes to be paid or refunded for the current period by applying the provisions of the enacted tax law to the taxable income or excess of deductions over revenues. The Corporation determines deferred income taxes using the liability (or balance sheet) method. Under this method, the net deferred tax asset or liability is based on the tax effects of the differences between the book and tax bases of assets and liabilities, and enacted changes in tax rates and laws are recognized in the period in which they occur. Deferred income tax expense results from changes in deferred tax assets and liabilities between periods. Deferred tax assets are reduced by a valuation allowance if, based on the weight of the evidence available, it is more likely than not that some portion or all of a deferred tax asset will not be realized. The Corporation accounts for uncertain tax positions if it is more likely than not, based on the technical merits, that the tax position will be realized or sustained upon examination. The term more-likely-than-not means a likelihood of more than 50%; the terms examined and upon examination also include resolution of the related appeals or litigation processes, if any. A tax position that meets the more-likely-than-not recognition threshold is initially and subsequently measured as the largest amount of tax benefit that has a greater than 50% likelihood of being realized upon settlement with a taxing authority that has full knowledge of all relevant information. The determination of whether or not a tax position has met the more-likely-than-not recognition threshold considers the facts, circumstances, and information available at the reporting date and is subject to management’s judgment. The Corporation recognizes interest and penalties on income taxes, if any, as a component of income tax expense.
Retirement Plan	Retirement Plan The compensation cost of an employee’s pension benefit is recognized on the projected unit credit method over the employee’s approximate service period. The aggregate cost method is utilized for funding purposes.
Stock-based Compensation	Stock-based Compensation The ACNB Corporation 2009 Restricted Stock plan expired by its own terms after 10 years on February 24, 2019. The purpose of this plan was to provide employees and directors of the Bank who have responsibility for its growth with additional incentives by allowing them to acquire ownership in the Corporation and, thereby, encouraging them to contribute to the success of the Corporation. As of December 31, 2019 , 25,945 shares issued under the plan, of which 23,730 shares are fully vested and the remaining 2,215 will vest over the next year. No further shares may be issued under this restricted stock plan. The Corporation’s Registration Statement under the Securities Act of 1933 on Form S-8 for the ACNB Corporation 2009 Restricted Stock Plan was filed with the Securities and Exchange Commission on January 4, 2013. Post-Effective Amendment No. 1 to this Form S-8 was filed with the Commission on March 8, 2019, effectively transferring the 174,055 authorized, but not issued, shares under the ACNB Corporation 2009 Restricted Stock Plan to the ACNB Corporation 2018 Omnibus Stock Incentive Plan. On May 1, 2018, shareholders approved and ratified the ACNB Corporation 2018 Omnibus Stock Incentive Plan, effective as of March 20, 2018, in which awards shall not exceed, in the aggregate, 400,000 shares of common stock, plus any shares that are authorized, but not issued, under the ACNB Corporation 2009 Restricted Stock Plan. As of December 31, 2019 , 16,115 shares were issued under this plan, of which 5,372 are fully vested and the remaining 10,743 will vest over the next two years . The Corporation’s Registration Statement under the Securities Act of 1933 of Form S-8 for the ACNB Corporation 2018 Omnibus Stock Incentive Plan was filed with the Securities and Exchange Commission on March 8, 2019. In addition, on March 8, 2019, the Corporation filed Post-Effective Amendment No. 1 to the Registration Statement on Form S-8 for the ACNB Corporation 2009 Restricted Stock Plan to add the ACNB Corporation 2018 Omnibus Stock Incentive Plan to the registration statement. Plan expense is recognized over the vesting period of the stock issued under both plans.
Net Income per Share	Net Income per Share The Corporation has a simple capital structure. Basic earnings per share of common stock is computed based on 7,061,524 and 7,035,818 weighted average shares of common stock outstanding for 2019 and 2018 , respectively. All outstanding unvested restricted stock awards that contain rights to nonforfeitable dividends are considered participating for this calculation.
Advertising Costs	Advertising Costs Costs of advertising, which are included in marketing expenses, are expensed when incurred.
Off-Balance Sheet Credit-Related Financial Instruments	Off-Balance Sheet Credit-Related Financial Instruments In the ordinary course of business, the Corporation has entered into commitments to extend credit, including commitments under commercial lines of credit, and standby letters of credit. Such financial instruments are recorded when they are funded.
Transfers of Financial Assets	Transfers of Financial Assets Transfers of financial assets are accounted for as sales when control over the assets has been surrendered. Control over transferred assets is deemed to be surrendered when (1) the assets have been isolated from the Corporation, (2) the transferee obtains the right (free of conditions that constrain it from taking advantage of that right) to pledge or exchange the transferred assets, and (3) the Corporation does not maintain effective control over the transferred assets through an agreement to repurchase them before their maturity or the ability to unilaterally cause the holder to return specific assets.
Accumulated Other Comprehensive Loss	Accumulated Other Comprehensive Loss The components of the accumulated other comprehensive loss, net of taxes, are as follows: In thousands Unrealized Losses on Securities Pension Liability Accumulated Other Comprehensive Loss BALANCE — DECEMBER 31, 2019 $ 1,261 $ (7,114 ) $ (5,853 ) BALANCE — DECEMBER 31, 2018 $ (1,651 ) $ (7,566 ) $ (9,217 )
Segment Reporting	Segment Reporting The Bank acts as an independent community financial services provider, which offers traditional banking and related financial services to individual, business, and government customers. Through its branch and automated teller machine networks, the Bank offers a full array of commercial and community financial services, including the taking of time, savings, and demand deposits; the making of commercial, consumer, and mortgage loans; and the providing of other financial services. Management does not separately allocate expenses, including the cost of funding loan demand, between the commercial, community and mortgage banking operations of the Bank. As such, discrete financial information for commercial, community and mortgage banking operations is not available and segment reporting would not be meaningful. Please refer to Note S — “Segment and Related Information” for a discussion of insurance operations.
New Accounting Pronouncements	New Accounting Pronouncements The Corporation early adopted ASU 2017-04, Simplifying the Test for Goodwill Impairment. The ASU eliminates Step 2 of the goodwill impairment test. As such, an entity will perform its annual, or interim, goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An entity should recognize a goodwill impairment charge for the amount by which the reporting unit’s carrying amount exceeds its fair value. If fair value exceeds the carrying amount, no impairment should be recorded. Any loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. Impairment losses on goodwill cannot be reversed once recognized. An entity may still perform the optional qualitative assessment for a reporting unit to determine if it is more likely than not that goodwill is impaired. However, the ASU eliminates the requirement to perform a qualitative assessment for any reporting unit with a zero or negative carrying amount. Therefore, the same one-step impairment assessment will apply to all reporting units. However, for a reporting unit with a zero or negative carrying amount, the ASU adds a requirement to disclose the amount of goodwill allocated to it and the reportable segment in which it is included. The amendments in this ASU were early adopted in the 2018 fiscal year and did not have a material effect on the Corporation’s consolidated financial condition or results of operations. On January 1, 2019, the Corporation adopted ASU 2016-02, Leases , and all subsequent amendments to the ASU (collectively “Topic 842”). From the lessee’s perspective, the new standard establishes a right-of-use (ROU) model that requires a lessee to record an ROU asset and a lease liability on the balance sheet for all leases with terms longer than 12 months. Leases are classified as either finance or operating, with classification affecting the pattern of expense recognition in the income statement for a lessee. Under the optional transition method, only the most recent period presented reflects the adoption of Topic 842 and the comparative prior periods are reported under the previous guidance in Topic 840. The Corporation recorded a $4 million right-of-use asset and lease liability, which represents all of its operating lease commitments, based on the present value of committed lease payments. The ASU offers lessors a practical expedient that mirrors the practical expedient already provided to lessees in ASU 2016-02, Leases (Topic 842). The Corporation adopted the new practical expedient which will allow the Corporation to elect, by class of underlying asset, to not separate nonlease components from the associated lease component when specified conditions are met. Examples of nonlease components include equipment maintenance services, common area maintenance services in real estate, or other goods or services provided to the lessee apart from the right to use the underlying asset. The practical expedient must be applied consistently for all lease contracts. The effect on operations and capital adequacy was not material. On January 1, 2019, the Corporation adopted ASU 2017-08, Premium Amortization on Purchased Callable Debt Securities . The ASU shortens the amortization period for premiums on purchased callable debt securities to the earliest call date (i.e., yield-to-earliest call amortization), rather than amortizing over the full contractual term. The ASU does not change the accounting for securities held at a discount. The amendments apply to callable debt securities with explicit, noncontingent call features that are callable at fixed prices and on preset dates. If a security may be prepaid based upon prepayments of the underlying loans, not because the issuer exercised a date specific call option, it is excluded from the scope of the new standard. However, for instruments with contingent call features, once the contingency is resolved and the security is callable at a fixed price and preset date, the security is within the scope of the amendments. Further, the amendments apply to all premiums on callable debt securities, regardless of how they were generated. The amendments require companies to reset the effective yield using the payment terms of the debt security if the call option is not exercised on the earliest call date. If the security has additional future call dates, any excess of the amortized cost basis over the amount repayable by the issuer at the next call date should be amortized to the next call date. The adoption of this ASU did not have a material effect on the Corporation’s consolidated financial condition or results of operations. The Corporation adopted ASU 2018-09, Codification Improvements . The ASU contains various improvements to various topics in the codification, including clarification that an entity must disclose the required and actual amounts of regulatory capital for each measure of regulatory capital for which the entity must comply. The adoption of this ASU did not impact the Corporation’s consolidated financial condition or results of operations since the Corporation already discloses capital requirements within the Management’s Discussion and Analysis section of this Form 10-K. The Corporation early adopted ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement. This ASU removes, modifies and adds to existing fair value measurement disclosure requirements. The ASU would be effective for all entities in fiscal years beginning after December 15, 2019, including interim periods, which is first effective for calendar year entities in the March 31, 2020, interim financial statements. In addition, an entity may early adopt any of the removed or modified disclosures immediately and delay adoption of the new disclosures until the effective date. The adoption of this ASU did not have a material effect on the Corporation’s consolidated financial condition or results of operations. ASU 2016-13 In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. ASU 2016-13 requires credit losses on most financial assets measured at amortized cost and certain other instruments to be measured using an expected credit loss model (referred to as the current expected credit loss (CECL) model). Under this model, entities will estimate credit losses over the entire contractual term of the instrument (considering estimated prepayments, but not expected extensions or modifications unless reasonable expectation of a troubled debt restructuring exists) from the date of initial recognition of that instrument. The ASU also replaces the current accounting model for purchased credit impaired loans and debt securities. The allowance for credit losses for purchased financial assets with a more-than insignificant amount of credit deterioration since origination (“PCD assets”), should be determined in a similar manner to other financial assets measured on an amortized cost basis. However, upon initial recognition, the allowance for credit losses is added to the purchase price (“gross up approach”) to determine the initial amortized cost basis. The subsequent accounting for PCD financial assets is the same expected loss model described above. Further, the ASU made certain targeted amendments to the existing impairment model for available-for-sale (AFS) debt securities. For an AFS debt security for which there is neither the intent nor a more-likely-than-not requirement to sell, an entity will record credit losses as an allowance rather than a write-down of the amortized cost basis. Certain incremental disclosures are required. Until recently, the new CECL standard was expected to become effective for the Corporation on January 1, 2020, and for interim periods within that year. In October 2019, FASB voted to delay implementation of the new CECL standard for certain companies, including those companies that qualify as a smaller reporting company under SEC rules, until January 1, 2023. The Corporation currently expects to continue to qualify as a smaller reporting company, based upon the current SEC definition, and as a result, will likely be able to defer implementation of the new CECL standard for a period of time. The Corporation will not early adopt as of January 1, 2020, but will continue to review factors that might indicate that the full deferral time period should not be used. The Corporation continues to evaluate the impact the CECL model will have on the accounting for credit losses, but the Corporation expects to recognize a one-time cumulative-effect adjustment to the allowance for loan losses as of the beginning of the first reporting period in which the new standard is effective, consistent with regulatory expectations set forth in interagency guidance issued at the end of 2016. The Corporation cannot yet determine the magnitude of any such one-time cumulative adjustment or of the overall impact of the new standard on its consolidated financial condition or results of operations. Management has developed a committee to address CECL and the committee is currently evaluating options to comply with the ASU in a timely manner. ASU 2018-14 In August 2018, the FASB issued ASU 2018-14, Compensation—Retirement Benefits—Defined Benefit Plans—General (Topic 715-20): Disclosure Framework—Changes to the Disclosure Requirements for Defined Benefit Plans. The ASU removes the following disclosures: • the amounts in accumulated other comprehensive income that the entity expects to recognize in net periodic benefit cost during the next fiscal year; • the amount and timing of plan assets expected to be returned to the employer; and, • certain related party disclosures. The ASU clarifies the following disclosure requirements: • the projected benefit obligation (PBO) and fair value of plan assets for plans with PBOs in excess of plan assets must be disclosed; and, • the accumulated benefit obligation (ABO) and fair value of plan assets for plans with ABOs in excess of plan assets must be disclosed. The ASU adds the following disclosure requirements: • the weighted-average interest crediting rates for cash balance plans and other plans with promised interest crediting rates; and, • an explanation of the reasons for significant gains and losses related to changes in the benefit obligation for the period. The ASU is effective for public business entities in fiscal years ending after December 15, 2020. Early adoption is permitted. The Corporation is currently evaluating the impact this ASU will have on its consolidated financial condition or results of operations.

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Schedule Of Components Of The Accumulated Other Comprehensive Loss, Net Of Taxes	The components of the accumulated other comprehensive loss, net of taxes, are as follows: In thousands Unrealized Losses on Securities Pension Liability Accumulated Other Comprehensive Loss BALANCE — DECEMBER 31, 2019 $ 1,261 $ (7,114 ) $ (5,853 ) BALANCE — DECEMBER 31, 2018 $ (1,651 ) $ (7,566 ) $ (9,217 )

SECURITIES (Tables)

SECURITIES (Tables)	12 Months Ended
	Dec. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Unrealized Gain (Loss) on Investments	Amortized cost and fair value at December 31, 2019 and 2018 , were as follows: In thousands Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value SECURITIES AVAILABLE FOR SALE December 31, 2019 U.S. Government and agencies $ 113,569 $ 849 $ 169 $ 114,249 Mortgage-backed securities, residential 64,699 980 87 65,592 State and municipal 10,940 70 14 10,996 $ 189,208 $ 1,899 $ 270 $ 190,837 December 31, 2018 U.S. Government and agencies $ 120,420 $ 142 $ 2,149 $ 118,413 Mortgage-backed securities, residential 33,960 194 343 33,811 State and municipal 9,482 60 36 9,506 $ 163,862 $ 396 $ 2,528 $ 161,730 SECURITIES HELD TO MATURITY December 31, 2019 U.S. Government and agencies $ 4,000 $ 8 $ — $ 4,008 Mortgage-backed securities, residential 15,234 76 37 15,273 $ 19,234 $ 84 $ 37 $ 19,281 December 31, 2018 U.S. Government and agencies $ 7,000 $ — $ 69 $ 6,931 Mortgage-backed securities, residential 20,266 4 290 19,980 $ 27,266 $ 4 $ 359 $ 26,911 The required fair value disclosures are as follows: In thousands Fair Value at January 1, 2019 Unrealized Gains Unrealized Losses Fair Value at December 31, 2019 DECEMBER 31, 2019 CRA Mutual Fund $ 1,012 $ 33 $ — $ 1,045 Stock in other banks 827 234 — 1,061 $ 1,839 $ 267 $ — $ 2,106 In thousands Fair Value at January 1, 2018 Unrealized Gains Unrealized Losses Fair Value at December 31, 2018 DECEMBER 31, 2018 CRA Mutual Fund $ 1,044 $ — $ 32 $ 1,012 Stock in other banks 749 247 169 827 $ 1,793 $ 247 $ 201 $ 1,839
Schedule of Unrealized Loss on Investments	The following table shows the Corporation’s investments’ gross unrealized losses and fair value, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position, at December 31, 2019 and 2018 : Less than 12 Months 12 Months or More Total In thousands Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses SECURITIES AVAILABLE FOR SALE December 31, 2019 U.S. Government and agencies $ — $ — $ 47,425 $ 169 $ 47,425 $ 169 Mortgage-backed securities, residential 16,208 82 1,424 5 17,632 87 State and municipal 3,233 13 502 1 3,735 14 $ 19,441 $ 95 $ 49,351 $ 175 $ 68,792 $ 270 December 31, 2018 U.S. Government and agencies $ 1,997 $ 5 $ 87,216 $ 2,144 $ 89,213 $ 2,149 Mortgage-backed securities, residential 9,410 134 8,586 209 17,996 343 State and municipal — — 2,696 36 2,696 36 $ 11,407 $ 139 $ 98,498 $ 2,389 $ 109,905 $ 2,528 SECURITIES HELD TO MATURITY December 31, 2019 Mortgage-backed securities, residential $ 6,587 $ 24 $ 3,161 $ 13 $ 9,748 $ 37 $ 6,587 $ 24 $ 3,161 $ 13 $ 9,748 $ 37 December 31, 2018 U.S. Government and agencies $ 2,975 $ 25 $ 3,956 $ 44 $ 6,931 $ 69 Mortgage-backed security, residential 5,408 59 12,636 231 18,044 290 $ 8,383 $ 84 $ 16,592 $ 275 $ 24,975 $ 359
Investments Classified by Contractual Maturity Date	Amortized cost and fair value at December 31, 2019 , by contractual maturity, where applicable, are shown below. Expected maturities will differ from contractual maturities because issuers may have the right to call or prepay with or without penalties. Available for Sale Held to Maturity In thousands Amortized Cost Fair Value Amortized Cost Fair Value 1 year or less $ 20,926 $ 20,953 $ 4,000 $ 4,008 Over 1 year through 5 years 98,502 99,220 — — Over 5 years through 10 years 199 202 — — Over 10 years 4,882 4,870 — — Mortgage-backed securities, residential 64,699 65,592 15,234 15,273 $ 189,208 $ 190,837 $ 19,234 $ 19,281

LOANS AND ALLOWANCE FOR LOAN _2

LOANS AND ALLOWANCE FOR LOAN LOSSES (Tables)	12 Months Ended
	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable, Gross, Allowance, and Net [Abstract]
Classes Of The Loan Portfolio Summarized By The Aggregate Risk Rating	The following tables present the classes of the loan portfolio summarized by the aggregate pass rating and the classified ratings of special mention, substandard and doubtful within the Corporation’s internal risk rating system as of December 31, 2019 and 2018 : In thousands Pass Special Substandard Doubtful Total December 31, 2019 Originated Loans Commercial and industrial $ 132,791 $ 12,249 $ 716 $ — $ 145,756 Commercial real estate 414,077 28,264 9,595 — 451,936 Commercial real estate construction 22,905 1,272 — — 24,177 Residential mortgage 364,814 6,279 251 — 371,344 Home equity lines of credit 92,372 627 83 — 93,082 Consumer 13,331 — — — 13,331 Total Originated Loans 1,040,290 48,691 10,645 — 1,099,626 Acquired Loans Commercial and industrial 3,007 374 178 — 3,559 Commercial real estate 100,199 11,537 3,376 — 115,112 Commercial real estate construction 1,542 697 — — 2,239 Residential mortgage 33,349 2,089 1,555 — 36,993 Home equity lines of credit 14,603 45 317 — 14,965 Consumer 107 — — — 107 Total Acquired Loans 152,807 14,742 5,426 — 172,975 Total Loans Commercial and industrial 135,798 12,623 894 — 149,315 Commercial real estate 514,276 39,801 12,971 — 567,048 Commercial real estate construction 24,447 1,969 — — 26,416 Residential mortgage 398,163 8,368 1,806 — 408,337 Home equity lines of credit 106,975 672 400 — 108,047 Consumer 13,438 — — — 13,438 Total Loans $ 1,193,097 $ 63,433 $ 16,071 $ — $ 1,272,601 In thousands Pass Special Substandard Doubtful Total December 31, 2018 Originated Loans Commercial and industrial $ 166,035 $ 2,902 $ 161 $ — $ 169,098 Commercial real estate 393,987 18,079 7,899 — 419,965 Commercial real estate construction 15,471 835 — — 16,306 Residential mortgage 381,525 6,492 733 — 388,750 Home equity lines of credit 90,941 334 — — 91,275 Consumer 14,174 — — — 14,174 Total Originated Loans 1,062,133 28,642 8,793 — 1,099,568 Acquired Loans Commercial and industrial 4,803 134 147 — 5,084 Commercial real estate 120,321 5,112 3,525 — 128,958 Commercial real estate construction 3,276 716 — — 3,992 Residential mortgage 41,193 1,896 2,460 — 45,549 Home equity lines of credit 18,614 88 386 — 19,088 Consumer 226 — — — 226 Total Acquired Loans 188,433 7,946 6,518 — 202,897 Total Loans Commercial and industrial 170,838 3,036 308 $ — 174,182 Commercial real estate 514,308 23,191 11,424 — 548,923 Commercial real estate construction 18,747 1,551 — — 20,298 Residential mortgage 422,718 8,388 3,193 — 434,299 Home equity lines of credit 109,555 422 386 — 110,363 Consumer 14,400 — — — 14,400 Total Loans $ 1,250,566 $ 36,588 $ 15,311 $ — $ 1,302,465
Schedule Of Changes In Accretable Yields Of Acquired Loans	The following table provides changes in accretable yield for all acquired loans accounted for under ASC 310-30. Loans accounted for under ASC 310-20 are not included in this table. In thousands Year Ended December 31, 2019 Year Ended December 31, 2018 Balance at beginning of period $ 891 $ 1,234 Acquisitions of impaired loans — — Reclassification from non-accretable differences 492 402 Accretion to loan interest income (741 ) (745 ) Balance at end of period $ 642 $ 891
Impaired Loans By Loan Portfolio Class	The following table summarizes information relative to impaired loans by loan portfolio class as of December 31, 2019 and 2018 : Impaired Loans with Allowance Impaired Loans with No Allowance In thousands Recorded Investment Unpaid Principal Balance Related Allowance Recorded Investment Unpaid Principal Balance December 31, 2019 Commercial and industrial $ 65 $ 65 $ 42 $ — $ — Commercial real estate — — — 7,383 7,383 Commercial real estate construction — — — — — Residential mortgage — — — 171 171 Home equity lines of credit — — — 83 83 Total $ 65 $ 65 $ 42 $ 7,637 $ 7,637 December 31, 2018 Commercial and industrial $ — $ — $ — $ — $ — Commercial real estate — — — 6,763 6,763 Commercial real estate construction — — — — — Residential mortgage — — — 537 537 Home equity lines of credit — — — — — Total $ — $ — $ — $ 7,300 $ 7,300
Average Of Impaired Loans And Related Interest Income By Loan Portfolio Class	The following table summarizes information in regards to average of impaired loans and related interest income by loan portfolio class: Impaired Loans with Allowance Impaired Loans with No Allowance In thousands Average Recorded Investment Interest Income Average Recorded Investment Interest Income December 31, 2019 Commercial and industrial $ 27 $ — $ — $ — Commercial real estate — — 6,625 612 Commercial real estate construction — — — — Residential mortgage — — 422 8 Home equity lines of credit — — 35 — Total $ 27 $ — $ 7,082 $ 620 December 31, 2018 Commercial and industrial $ 436 $ — $ 73 $ 44 Commercial real estate — — 7,372 216 Commercial real estate construction — — — — Residential mortgage 75 — 275 — Home equity lines of credit 30 — — — Total $ 541 $ — $ 7,720 $ 260
Nonaccrual Loans By Classes Of The Loan Portfolio	The following table presents nonaccrual loans by loan portfolio class as of December 31, 2019 and 2018 , the table below excludes $6.9 million in purchase credit impaired loans, net of unamortized fair value adjustments: In thousands 2019 2018 Commercial and industrial $ 65 $ — Commercial real estate 3,600 2,880 Commercial real estate construction — — Residential mortgage 171 537 Home equity lines of credit 83 — Total $ 3,919 $ 3,417
Loan Portfolio Summarized By The Past Due Status	The following table presents the classes of the loan portfolio summarized by the past due status as of December 31, 2019 and 2018 : In thousands 30-59 Days Past Due 60-89 Days Past Due >90 Days Past Due Total Past Due Current Total Loans Receivable Loans Receivable >90 Days and Accruing December 31, 2019 Originated Loans Commercial and industrial $ 16 $ — $ 4 $ 20 $ 145,736 $ 145,756 $ 4 Commercial real estate 325 2,247 1,286 3,858 448,078 451,936 — Commercial real estate construction 78 — — 78 24,099 24,177 — Residential mortgage 1,625 949 1,232 3,806 367,538 371,344 1,061 Home equity lines of credit 141 77 — 218 92,864 93,082 — Consumer 38 8 19 65 13,266 13,331 19 Total originated loans 2,223 3,281 2,541 8,045 1,091,581 1,099,626 1,084 Acquired Loans Commercial and industrial — 23 — 23 3,536 3,559 — Commercial real estate 1,063 — — 1,063 114,049 115,112 — Commercial real estate construction — — — — 2,239 2,239 — Residential mortgage 293 257 120 670 36,323 36,993 120 Home equity lines of credit 236 93 15 344 14,621 14,965 15 Consumer — — — — 107 107 — Total acquired loans 1,592 373 135 2,100 170,875 172,975 135 Total Loans Commercial and industrial 16 23 4 43 149,272 149,315 4 Commercial real estate 1,388 2,247 1,286 4,921 562,127 567,048 — Commercial real estate construction 78 — — 78 26,338 26,416 — Residential mortgage 1,918 1,206 1,352 4,476 403,861 408,337 1,181 Home equity lines of credit 377 170 15 562 107,485 108,047 15 Consumer 38 8 19 65 13,373 13,438 19 Total Loans $ 3,815 $ 3,654 $ 2,676 $ 10,145 $ 1,262,456 $ 1,272,601 $ 1,219 In thousands 30-59 Days Past Due 60-89 Days Past Due >90 Days Past Due Total Past Due Current Total Loans Receivable Loans Receivable >90 Days and Accruing December 31, 2018 Originated Loans Commercial and industrial $ 49 $ 49 $ 4 $ 102 $ 168,996 $ 169,098 $ 4 Commercial real estate 775 550 114 1,439 418,526 419,965 — Commercial real estate construction — — — — 16,306 16,306 — Residential mortgage 1,783 529 2,361 4,673 384,077 388,750 1,824 Home equity lines of credit 16 38 375 429 90,846 91,275 375 Consumer 36 14 — 50 14,124 14,174 — Total originated loans 2,659 1,180 2,854 6,693 1,092,875 1,099,568 2,203 Acquired Loans Commercial and industrial 27 — — 27 5,057 5,084 — Commercial real estate 64 — 851 915 128,043 128,958 851 Commercial real estate construction 343 — 77 420 3,572 3,992 77 Residential mortgage 1,235 251 907 2,393 43,156 45,549 125 Home equity lines of credit 227 — 89 316 18,772 19,088 89 Consumer — 7 — 7 219 226 — Total acquired loans 1,896 258 1,924 4,078 198,819 202,897 1,142 Total Loans Commercial and industrial 76 49 4 129 174,053 174,182 4 Commercial real estate 839 550 965 2,354 546,569 548,923 851 Commercial real estate construction 343 — 77 420 19,878 20,298 77 Residential mortgage 3,018 780 3,268 7,066 427,233 434,299 1,949 Home equity lines of credit 243 38 464 745 109,618 110,363 464 Consumer 36 21 — 57 14,343 14,400 — Total Loans $ 4,555 $ 1,438 $ 4,778 $ 10,771 $ 1,291,694 $ 1,302,465 $ 3,345
Allowance For Loan Losses And Recorded Investment In Financing Receivables	The following table summarizes the allowance for loan losses and recorded investment in loans: In thousands Commercial and Industrial Commercial Real Estate Commercial Real Estate Construction Residential Mortgage Home Equity Lines of Credit Consumer Unallocated Total December 31, 2019 Allowance for loan losses Beginning balance- January 1, 2019 $ 2,597 $ 6,208 $ 203 $ 2,814 $ 611 $ 692 $ 839 $ 13,964 Charge-offs (163 ) (78 ) — (173 ) (301 ) (202 ) — (917 ) Recoveries 66 10 — 37 12 63 — 188 Provisions (100 ) 553 95 (123 ) 297 97 (219 ) 600 Ending balance- December 31, 2019 $ 2,400 $ 6,693 $ 298 $ 2,555 $ 619 $ 650 $ 620 $ 13,835 Ending balance: individually evaluated for impairment $ 42 $ — $ — $ — $ — $ — $ — $ 42 Ending balance: collectively evaluated for impairment $ 2,358 $ 6,693 $ 298 $ 2,555 $ 619 $ 650 $ 620 $ 13,793 Loans receivables Ending balance $ 149,315 $ 567,048 $ 26,416 $ 408,337 $ 108,047 $ 13,438 $ — $ 1,272,601 Ending balance: individually evaluated for impairment $ 65 $ 7,383 $ — $ 171 $ 83 $ — $ — $ 7,702 Ending balance: collectively evaluated for impairment $ 149,250 $ 559,665 $ 26,416 $ 408,166 $ 107,964 $ 13,438 $ — $ 1,264,899 December 31, 2018 Allowance for loan losses Beginning balance- January 1, 2018 $ 3,219 $ 5,228 $ 126 $ 3,226 $ 612 $ 749 $ 816 $ 13,976 Charge-offs (934 ) (33 ) — (530 ) (148 ) (165 ) — (1,810 ) Recoveries 36 — 103 32 — 7 — 178 Provisions 276 1,013 (26 ) 86 147 101 23 1,620 Ending balance- December 31, 2018 $ 2,597 $ 6,208 $ 203 $ 2,814 $ 611 $ 692 $ 839 $ 13,964 Ending balance: individually evaluated for impairment $ — $ — $ — $ — $ — $ — $ — $ — Ending balance: collectively evaluated for impairment $ 2,597 $ 6,208 $ 203 $ 2,814 $ 611 $ 692 $ 839 $ 13,964 Loans receivables Ending balance $ 174,182 $ 548,923 $ 20,298 $ 434,299 $ 110,363 $ 14,400 $ — $ 1,302,465 Ending balance: individually evaluated for impairment $ — $ 6,763 $ — $ 537 $ — $ — $ — $ 7,300 Ending balance: collectively evaluated for impairment $ 174,182 $ 542,160 $ 20,298 $ 433,762 $ 110,363 $ 14,400 $ — $ 1,295,165

PREMISES AND EQUIPMENT (Tables)

PREMISES AND EQUIPMENT (Tables)	12 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Premises and equipment	Premises and equipment at December 31 were as follows: In thousands 2019 2018 Land $ 5,050 $ 5,050 Buildings and improvements 27,915 27,509 Furniture and equipment 14,562 14,111 Construction in process 928 460 48,455 47,130 Accumulated depreciation (22,731 ) (20,721 ) $ 25,724 $ 26,409

DEPOSITS (Tables)

DEPOSITS (Tables)	12 Months Ended
	Dec. 31, 2019
Interest-bearing Deposit Liabilities [Abstract]
Schedule Of Deposits	Deposits were comprised of the following as of December 31: In thousands 2019 2018 Non-interest bearing demand $ 314,377 $ 302,394 Interest bearing demand 152,275 160,718 Savings 537,755 516,872 Time certificates of deposit of $250,000 or less 339,876 307,407 Time certificates of deposit greater than $250,000 67,977 60,701 $ 1,412,260 $ 1,348,092
Schedule Of Maturities Of Time Certificates Of Deposits	Scheduled maturities of time certificates of deposit at December 31, 2019 , were as follows: Years Ending In thousands 2020 $ 258,528 2021 109,470 2022 26,627 2023 6,164 2024 7,064 $ 407,853

LEASE COMMITMENTS (Tables)

LEASE COMMITMENTS (Tables)	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Supplemental Balance Sheet Information	The following right-of-use assets and lease liabilities are reported within the consolidated statements of condition as follows: In thousands December 31, 2019 Operating Leases: Right of use assets $ 3,502 Lease liabilities 3,502 Supplemental balance sheet information related to leases was as follows for the year ended December 31, 2019 : Operating Leases: Weighted average remaining lease term 7.1 years Weighted average discount rate 5.71 %
Future Minimum Rental Payments	The following summarizes the remaining scheduled future minimum lease payments for operating leases as of December 31, 2019 : Years Ending In thousands 2020 $ 756 2021 665 2022 544 2023 480 2024 466 Thereafter 1,685 Total minimum lease payments 4,596 Less: Amount representing interest (1) 1,094 Present value of net minimum lease payments $ 3,502 (1) Amount necessary to reduce net minimum lease payments to present value calculated at the Corporation’s incremental borrowing rate.

BORROWINGS (Tables)

BORROWINGS (Tables)	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Schedule of Short-term Debt	Short-term borrowings and weighted-average interest rates at December 31 are as follows: 2019 2018 Dollars in thousands Amount Rate Amount Rate FHLB overnight advance $ — — % $ 32 2.62 % Securities sold under repurchase agreements 33,435 0.12 34,616 0.12 $ 33,435 0.12 % $ 34,648 0.12 %
Offsetting Liabilities	The following table presents the short-term borrowings subject to an enforceable master netting arrangement or repurchase agreement as of December 31, 2019 and 2018 : Gross Amounts Not Offset in the Statements of Condition Dollars in thousands Gross Amounts of Recognized Liabilities Gross Amounts Offset in the Statements of Condition Net Amounts of Liabilities Presented in the Statements of Condition Financial Instruments Cash Collateral Pledged Net Amount December 31, 2019 Repurchase agreements Commercial customers and government entities (a) $ 33,435 $ — $ 33,435 $ (33,435 ) $ — $ — December 31, 2018 Repurchase agreements Commercial customers and government entities (a) $ 34,616 $ — $ 34,616 $ (34,616 ) $ — $ — (a) As of December 31, 2019 and 2018 , the fair value of securities pledged in connection with repurchase agreements was $34,582,000 and $39,788,000 , respectively.
Schedule of Maturities of Long-term Debt	A summary of long-term debt as of December 31 is as follows: 2019 2018 Dollars in thousands Amount Rate Amount Rate FHLB fixed-rate advances maturing: 2019 $ — — % $ 23,500 1.73 % 2020 20,000 1.87 % 20,000 1.87 % 2021 22,716 2.10 % 22,716 2.10 % 2022 11,000 2.69 % 9,000 2.70 % 2023 5,000 2.60 % — — % Loan Payable to local bank 1,830 4.50 % 2,300 4.50 % Loan Payable to local bank 750 4.50 % 1,000 5.25 % Trust preferred subordinated debt 5,000 6.39 % 5,000 6.39 % $ 66,296 2.58 % $ 83,516 2.47 %

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Expense (Benefit)	The components of income tax expense for the years ended December 31, 2019 and 2018 , are as follows: In thousands 2019 2018 Federal: Current $ 5,169 $ 4,036 Deferred 122 388 5,291 4,424 State: Current 338 479 Deferred 16 69 354 548 $ 5,645 $ 4,972
Schedule of Reconciliations of the Statutory Federal Income Tax	Reconciliations of the statutory federal income tax to the income tax expense reported in the consolidated statements of income for the years ended December 31, 2019 and 2018 , are as follows: Percentage of Income before Income Taxes 2019 2018 Federal income tax at statutory rate 21.0 % 21.0 % State income taxes, net of federal benefit 1.0 % 1.6 % Tax-exempt income (1.5 )% (1.7 )% Earnings on investment in bank-owned life insurance (0.8 )% (0.9 )% Rehabilitation and low-income housing credits (1.0 )% (1.1 )% Reduction of federal tax rate — % — % Other 0.5 % (0.3 )% 19.2 % 18.6 %
Components of Deferred Tax Assets and Liabilities	Components of deferred tax assets and liabilities at December 31 were as follows: In thousands 2019 2018 Deferred tax assets: Allowance for loan losses $ 2,995 $ 3,054 Available for sale securities — 409 Accrued deferred compensation 941 884 Pension 2,033 2,207 Other-than-temporary impairment 43 43 Nonaccrual interest 194 192 Deferred director fees 664 589 Acquisition accounting 377 785 Other 604 602 7,851 8,765 Deferred tax liabilities: Deferred loan fees 94 101 Available for sale securities 391 — Prepaid pension benefit cost 4,154 4,289 Prepaid expenses 129 130 Accumulated depreciation 221 347 Goodwill/intangibles 1,181 1,056 6,170 5,923 Net Deferred Tax Asset included in Other Assets $ 1,681 $ 2,842

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	For assets measured at fair value, the fair value measurements by level within the fair value hierarchy, and the basis of measurement used at December 31, 2019 and 2018 , are as follows: Fair Value Measurements at December 31, 2019 In thousands Basis Total Level 1 Level 2 Level 3 U.S. Government and agencies $ 114,249 $ — $ 114,249 $ — Mortgage-backed securities, residential 65,592 — 65,592 — State and municipal 10,996 — 10,996 — Total securities available for sale Recurring $ 190,837 $ — $ 190,837 $ — Equity securities with readily determinable fair values Recurring $ 2,106 $ 2,106 $ — $ — Collateral dependent impaired loans Non-recurring $ 3,806 $ — $ — $ 3,806 Fair Value Measurements at December 31, 2018 In thousands Basis Total Level 1 Level 2 Level 3 U.S. Government and agencies $ 118,413 $ — $ 118,413 $ — Mortgage-backed securities, residential 33,811 — 33,811 — State and municipal 9,506 — 9,506 — Total securities available for sale Recurring $ 161,730 $ — $ 161,730 $ — Equity securities with readily determinable fair values Recurring $ 1,839 $ 1,839 $ — $ — Collateral dependent impaired loans Non-recurring $ 3,883 $ — $ — $ 3,883
Fair Value Inputs, Assets, Quantitative Information	The following table presents additional quantitative information about assets measured at fair value on a nonrecurring basis for which the Corporation has utilized Level 3 inputs to determine fair value: Quantitative Information about Level 3 Fair Value Measurements Dollars in thousands Fair Value Estimate Valuation Technique Unobservable Input Range Weighted Average December 31, 2019 Impaired loans $ 3,806 Appraisal of collateral (1) Appraisal adjustments (2) (10) - (50)% (15 )% December 31, 2018 Impaired loans $ 3,883 Appraisal of collateral (1) Appraisal adjustments (2) (10) - (50)% (16 )% (1) Fair value is generally determined through management’s estimate or independent third-party appraisals of the underlying collateral, which generally includes various Level 3 inputs which are not observable. (2) Appraisals may be adjusted downward by management for qualitative factors such as economic conditions and estimated liquidation expenses. The range of liquidation expenses and other appraisal adjustments are presented as a percentage of the appraisal. Higher downward adjustments are caused by negative changes to the collateral or conditions in the real estate market, actual offers or sales contracts received, and/or age of the appraisal.
Fair Value, by Balance Sheet Grouping	The following presents the carrying amount, fair value, and placement in the fair value hierarchy of the Corporation’s financial instruments at December 31, 2019 : December 31, 2019 In thousands Carrying Amount Fair Value Level 1 Level 2 Level 3 Financial assets: Cash and due from banks $ 16,878 $ 16,878 $ 9,542 $ 7,336 $ — Interest-bearing deposits in banks 97,478 97,478 97,478 — — Equity securities available for sale 2,106 2,106 2,106 — — Investment securities available for sale 190,837 190,837 — 190,837 — Investment securities held to maturity 19,234 19,281 — 19,281 — Loans held for sale 2,406 2,406 — 2,406 — Loans, less allowance for loan losses 1,258,766 1,263,014 — — 1,263,014 Accrued interest receivable 4,368 4,368 — 4,368 — Restricted investment in bank stocks 3,644 3,644 — 3,644 — Financial liabilities: Demand deposits and savings 1,004,407 1,004,407 — 1,004,407 — Time deposits 407,853 409,426 — 409,426 — Short-term borrowings 33,435 33,435 — 33,435 — Long-term borrowings 61,296 61,965 — 61,965 — Trust preferred subordinated debt 5,000 4,711 — 4,711 — Accrued interest payable 2,676 2,676 — 2,676 — Off-balance sheet financial instruments — — — — — The following presents the carrying amount, exit pricing concept fair value, and placement in the fair value hierarchy of the Corporation’s financial instruments at December 31, 2018 : December 31, 2018 In thousands Carrying Amount Fair Value Level 1 Level 2 Level 3 Financial assets: Cash and due from banks $ 20,105 $ 20,105 $ 8,190 $ 11,915 $ — Interest-bearing deposits in banks 20,800 20,800 20,800 — — Equity securities available for sale 1,839 1,839 1,839 — — Investment securities available for sale 161,730 161,730 — 161,730 — Investment securities held to maturity 27,266 26,911 — 26,911 — Loans held for sale 408 408 — 408 — Loans, less allowance for loan losses 1,288,501 1,272,393 — — 1,272,393 Accrued interest receivable 4,545 4,545 — 4,545 — Restricted investment in bank stocks 4,336 4,336 — 4,336 — Financial liabilities: Demand deposits and savings 979,964 979,964 — 979,964 — Time deposits 368,128 364,093 — 364,093 — Short-term borrowings 34,648 34,648 — 34,648 — Long-term borrowings 78,516 78,545 — 78,545 — Trust preferred subordinated debt 5,000 4,701 — 4,701 — Accrued interest payable 1,364 1,364 — 1,364 — Off-balance sheet financial instruments — — — — —

RETIREMENT PLANS (Tables)

RETIREMENT PLANS (Tables)	12 Months Ended
	Dec. 31, 2019
Postemployment Benefits [Abstract]
Schedule of Benefit Plan Funded Status	A measurement date of December 31 has been used for the fiscal years ended December 31, 2019 and 2018 . In thousands 2019 2018 Change in benefit obligation: Benefit obligation at beginning of year $ 30,338 $ 31,547 Service cost 696 860 Interest cost 1,213 1,096 Actuarial loss (gain) 3,603 (1,944 ) Benefits paid (1,316 ) (1,221 ) Projected benefit obligation at end of year 34,534 30,338 Change in plan assets: Fair value of plan assets at beginning of year 39,680 42,439 Actual return on plan assets 5,928 (1,538 ) Employer contribution — — Benefits paid (1,316 ) (1,221 ) Fair value of plan assets at end of year 44,292 39,680 Funded Status, included in other assets $ 9,758 $ 9,342 Amounts recognized in accumulated other comprehensive loss: Total net actuarial loss $ 9,147 $ 9,773 Prior service cost — — Total included in accumulated other comprehensive loss (pretax) $ 9,147 $ 9,773
Estimated Costs To Be Amortized From AOCI Into Net Periodic Pension Cost During The Next Fiscal Year	The estimated costs that will be amortized from accumulated other comprehensive loss into net periodic pension cost during the next fiscal year are as follows: In thousands Net loss $ 675 Prior service cost — $ 675
Components Of Net Periodic Benefit Costs (Income)	The components of net periodic benefit cost (income) related to the non-contributory, defined benefit pension plan for the years ended December 31 are as follows: In thousands 2019 2018 Components of net periodic benefit cost (income): Service cost $ 696 $ 860 Interest cost 1,213 1,096 Expected return on plan assets (2,549 ) (2,770 ) Recognized net actuarial loss 850 515 Amortization of prior service cost — — Net Periodic Benefit Cost (Income) 210 (299 ) Net loss 224 2,365 Amortization of net loss (850 ) (515 ) Amortization of prior service cost — — Total recognized in other comprehensive (income) loss $ (626 ) $ 1,850 Total recognized in net periodic benefit cost (income) and other comprehensive (income) loss $ (416 ) $ 1,551
Assumptions Used To Determine The Benefit Obligation and Net Periodic Benefit Cost (Income)	For the years ended December 31, 2019 and 2018 , the assumptions used to determine the benefit obligation are as follows: 2019 2018 Discount rate 3.20 % 4.10 % Rate of compensation increase 3.50 % 3.50 % For the years ended December 31, 2019 and 2018 , the assumptions used to determine the net periodic benefit cost (income) are as follows: 2019 2018 Discount rate 4.10 % 3.55 % Expected long-term rate of return on plan assets 6.75 % 6.75 % Rate of compensation increase 3.50 % 3.50 %
Pension Plan Weighted-Average Assets' Allocations	The Corporation’s pension plan weighted-average assets’ allocations at December 31, 2019 and 2018 , are as follows: 2019 2018 Equity securities 45 % 63 % Debt securities 42 % 34 % Short-term fixed income — % — % Real estate 13 % 3 % 100 % 100 %
Fair Value Measurements	Fair value measurements at December 31, 2019 , are as follows: In thousands Total Level 1 Level 2 Level 3 Equity securities $ 20,098 $ 2,854 $ 17,244 $ — Debt securities 18,516 — 18,516 — Real estate 5,678 — 5,678 — Fair value measurements at December 31, 2018 , are as follows: In thousands Total Level 1 Level 2 Level 3 Equity securities $ 25,150 $ 2,882 $ 22,268 $ — Debt securities 13,376 — 13,376 — Real estate 1,154 — 1,154 —
Future Benefit Payments	Based on current data and assumptions, the following benefit payments, which reflect expected future service, as appropriate, are: Years Ending In thousands 2020 $ 1,550 2021 1,670 2022 1,680 2023 1,800 2024 1,840 2025 - 2029 9,480

STOCKHOLDERS' EQUITY AND REGU_2

STOCKHOLDERS' EQUITY AND REGULATORY MATTERS (Tables)	12 Months Ended
	Dec. 31, 2019
Broker-Dealer, Net Capital Requirement, SEC Regulation [Abstract]
The Actual and Required Capital Amounts and Ratios	The actual and required capital amounts and ratios were as follows: Actual For Capital Adequacy Purposes To be Well Capitalized under Prompt Corrective Action Provisions Dollars in thousands Amount Ratio Amount (1) Ratio (1) Amount Ratio CORPORATION As of December 31, 2019 Tier 1 leverage ratio (to average assets) $ 176,403 10.19 % $ ≥69,239 ≥4.0% N/A N/A Common Tier 1 risk-based capital ratio (to risk-weighted assets) 176,403 14.50 ≥54,759 ≥4.5 N/A N/A Tier 1 risk-based capital ratio (to risk-weighted assets) 176,403 14.50 ≥73,012 ≥6.0 N/A N/A Total risk-based capital ratio (to risk-weighted assets) 190,319 15.64 ≥97,349 ≥8.0 N/A N/A As of December 31, 2018 Tier 1 leverage ratio (to average assets) $ 158,404 9.66 % $ ≥65,568 ≥4.0% N/A N/A Common Tier 1 risk-based capital ratio (to risk-weighted assets) 158,404 13.19 ≥54,026 ≥4.5 N/A N/A Tier 1 risk-based capital ratio (to risk-weighted assets) 158,404 13.19 ≥72,034 ≥6.0 N/A N/A Total risk-based capital ratio (to risk-weighted assets) 172,449 14.36 ≥96,046 ≥8.0 N/A N/A BANK As of December 31, 2019 Tier 1 leverage ratio (to average assets) $ 171,179 9.93 % $ ≥68,982 ≥4.0% $ ≥86,228 ≥5.0% Common Tier 1 risk-based capital ratio (to risk-weighted assets) 171,179 14.13 ≥54,514 ≥4.5 ≥78,742 ≥6.5 Tier 1 risk-based capital ratio (to risk-weighted assets) 171,179 14.13 ≥72,685 ≥6.0 ≥96,913 ≥8.0 Total risk-based capital ratio (to risk-weighted assets) 185,095 15.28 ≥96,913 ≥8.0 ≥121,142 ≥10.0 As of December 31, 2018 Tier 1 leverage ratio (to average assets) $ 154,215 9.44 % $ ≥65,348 ≥4.0% $ ≥81,686 ≥5.0% Common Tier 1 risk-based capital ratio (to risk-weighted assets) 154,215 12.89 ≥53,826 ≥4.5 ≥77,748 ≥6.5 Tier 1 risk-based capital ratio (to risk-weighted assets) 154,215 12.89 ≥71,768 ≥6.0 ≥95,690 ≥8.0 Total risk-based capital ratio (to risk-weighted assets) 168,260 14.07 ≥95,690 ≥8.0 ≥119,613 ≥10.0 (1) Amounts and ratios do not include capital conservation buffer.

FINANCIAL INSTRUMENTS WITH OF_2

FINANCIAL INSTRUMENTS WITH OFF-BALANCE SHEET RISK (Tables)	12 Months Ended
	Dec. 31, 2019
Risks and Uncertainties [Abstract]
Schedule of Fair Value, Off-balance Sheet Risks	A summary of the Corporation’s commitments at December 31 were as follows: In thousands 2019 2018 Commitments to extend credit $ 319,681 $ 279,729 Standby letters of credit 6,584 3,909

ACNB CORPORATION (PARENT COMP_2

ACNB CORPORATION (PARENT COMPANY ONLY) FINANCIAL INFORMATION (Tables)	12 Months Ended
	Dec. 31, 2019
Condensed Financial Information Disclosure [Abstract]
Statements of Condition	December 31, In thousands 2019 2018 ASSETS Cash $ 6,828 $ 7,391 Investment in banking subsidiary 176,689 156,651 Investment in other subsidiaries 10,473 9,389 Investments in low-income housing partnerships — 240 Securities and other assets 1,558 1,271 Receivable from banking subsidiary 812 518 Total Assets $ 196,360 $ 175,460 LIABILITIES AND STOCKHOLDERS’ EQUITY Long-term debt $ 6,830 $ 7,300 Other liabilities 14 23 Stockholders’ equity 189,516 168,137 Total Liabilities and Stockholders’ Equity $ 196,360 $ 175,460
Statements of Income	Years Ended December 31, In thousands 2019 2018 Dividends from banking subsidiary $ 6,920 $ 6,261 Gain on sale of securities — 47 Other income 282 35 7,202 6,343 Expenses 1,739 1,421 5,463 4,922 Income tax benefit 501 547 5,964 5,469 Equity in undistributed earnings of subsidiaries 17,757 16,279 Net Income $ 23,721 $ 21,748 Comprehensive Income $ 27,085 $ 19,623
Statements of Cash Flows	Years Ended December 31, In thousands 2019 2018 CASH FLOWS FROM OPERATING ACTIVITIES Net income $ 23,721 $ 21,748 Equity in undistributed earnings of subsidiaries (17,757 ) (16,279 ) Increase in receivable from banking subsidiary (294 ) (400 ) Gain on sale of securities — 47 Other (57 ) 669 Net Cash Provided by Operating Activities 5,613 5,785 CASH FLOWS FROM INVESTING ACTIVITIES — — Net Cash Used in Investing Activities — — CASH FLOWS USED IN FINANCING ACTIVITIES Repayments on long-term debt (470 ) (2,300 ) Proceeds from issuance of common stock 1,214 727 Dividends paid (6,920 ) (6,261 ) Net Cash Used in Financing Activities (6,176 ) (7,834 ) Net Decrease in Cash and Cash Equivalents (563 ) (2,049 ) CASH AND CASH EQUIVALENTS — BEGINNING 7,391 9,440 CASH AND CASH EQUIVALENTS — ENDING $ 6,828 $ 7,391

GOODWILL AND OTHER INTANGIBLES

GOODWILL AND OTHER INTANGIBLES (Tables)	12 Months Ended
	Dec. 31, 2019
Business Combinations [Abstract]
Carrying Value And Accumulated Amortization Of The Intangible Assets (RIG Customer Lists and New Windsor Core Deposit Intangibles)	The carrying value and accumulated amortization of the intangible assets (RIG customer lists and New Windsor core deposit intangibles) are as follows: 2019 2018 Dollars in thousands Gross Carrying Amount Accumulated Amortization Gross Carrying Amount Accumulated Amortization RIG amortized intangible assets 9,890 6,869 9,250 6,623 New Windsor core deposit intangibles 2,418 1,012 2,418 638 $ 12,308 $ 7,881 $ 11,668 $ 7,261
Expected Amortization Expense	Amortization of the intangible assets for the five years subsequent to December 31, 2019 , is expected to be as follows: Years Ending In thousands 2020 $ 590 2021 546 2022 502 2023 458 2024 406 Thereafter 1,925

SEGMENT AND RELATED INFORMATI_2

SEGMENT AND RELATED INFORMATION (Tables)	12 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
Segment Information	Segment information for 2019 and 2018 is as follows: In thousands Banking Insurance Total 2019 Net interest income and other income from external customers $ 71,713 $ 5,874 $ 77,587 Income before income taxes 27,870 1,496 29,366 Total assets 1,707,653 12,600 1,720,253 Capital expenditures 1,367 57 1,424 2018 Net interest income and other income from external customers $ 67,654 $ 5,389 $ 73,043 Income before income taxes 25,515 1,205 26,720 Total assets 1,634,750 12,974 1,647,724 Capital expenditures 1,341 402 1,743

SUMMARY OF SIGNIFICANT ACCOUN_4

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Narrative) (Details)	Jan. 11, 2020USD ($)directorloan_officesbank$ / sharesshares	Feb. 24, 2019	Jul. 01, 2017USD ($)	Sep. 30, 2019	Dec. 31, 2019USD ($)bankshares	Dec. 31, 2018USD ($)shares	Dec. 31, 2017shares	Mar. 08, 2019shares	Mar. 20, 2018shares	Feb. 24, 2009shares
Summary of Significant Accounting Policies [Line Items]
Number of community banking office locations, ACNB | bank					22
Number of community banking office locations, NWSB | bank					7
Business Acquisition, Pro Forma Assets					$ 1,720,253,000	$ 1,647,724,000
Business Acquisition, Pro Forma Deposits					1,412,260,000	1,348,092,000
Business Acquisition, Pro Forma Loans					1,258,766,000	1,288,501,000
Assets Held-in-trust					389,000,000	342,000,000
Total Loans Receivable					$ 1,272,601,000	1,302,465,000
Number of minimum months for corporation to order updated valuation					18 months
Post-employment benefit cost for continuing life insurance					$ 161,000	95,000
Foreclosed assets held for resale					$ 364,000	$ 155,000
2009 Restricted Stock Plan, number of shares authorized, but not issued (in shares) | shares								174,055
Weighted average number of shares outstanding, basic | shares					7,061,524	7,035,818
Right of use assets					$ 3,502,000	$ 0
Lease liabilities					3,502,000	0
Restricted Stock
Summary of Significant Accounting Policies [Line Items]
Compensation expense					322,000	186,000
Credit Concentration Risk
Summary of Significant Accounting Policies [Line Items]
Total Loans Receivable					$ 297,654,000
Concentration Risk, Percentage					23.40%
Residential Mortgage and Commercial Loans
Summary of Significant Accounting Policies [Line Items]
Threshold period past due to discontinue accrual interest on financing receivable					90 days
Consumer
Summary of Significant Accounting Policies [Line Items]
Total Loans Receivable					$ 13,438,000	14,400,000
Threshold period past due for charge off of financing receivable					120 days
Commercial real estate
Summary of Significant Accounting Policies [Line Items]
Total Loans Receivable					$ 567,048,000	$ 548,923,000
Commercial real estate | Maximum
Summary of Significant Accounting Policies [Line Items]
Financing receivable term					20 years
Loan-to-value ratio (no greater than)					80.00%
Residential Mortgage
Summary of Significant Accounting Policies [Line Items]
Loan-to-value ratio that requires private mortgage insurance (in excess of)					80.00%
Foreclosed assets held for resale					$ 83,000
Residential Mortgage | Maximum
Summary of Significant Accounting Policies [Line Items]
Financing receivable term					30 years
Loan-to-value ratio (no greater than)					80.00%
Home Equity Line of Credit | Maximum
Summary of Significant Accounting Policies [Line Items]
Financing receivable term					20 years
Loan-to-value ratio (no greater than)					90.00%
Buildings
Summary of Significant Accounting Policies [Line Items]
Useful life					40 years
Building Remodels and Additions
Summary of Significant Accounting Policies [Line Items]
Useful life					15 years
Bank Equipment | Minimum
Summary of Significant Accounting Policies [Line Items]
Useful life					5 years
Bank Equipment | Maximum
Summary of Significant Accounting Policies [Line Items]
Useful life					15 years
New Windsor
Summary of Significant Accounting Policies [Line Items]
Interest rate fair value discount			$ 731,000
Credit fair value discount			$ 4,500,000
Core Deposits
Summary of Significant Accounting Policies [Line Items]
Intangible asset amortization life					10 years
Customer Lists | Minimum
Summary of Significant Accounting Policies [Line Items]
Intangible asset amortization life					8 years
Customer Lists | Maximum
Summary of Significant Accounting Policies [Line Items]
Intangible asset amortization life					15 years
Accounting Standards Update 2016-02
Summary of Significant Accounting Policies [Line Items]
Right of use assets					$ 4,000,000
Lease liabilities					$ 4,000,000
ACNB Corporation 2009 Restricted Stock Plan
Summary of Significant Accounting Policies [Line Items]
2009 Restricted Stock plan, expiration period		10 years
Awards authorized (in shares) | shares										200,000
ACNB Corporation 2009 Restricted Stock Plan | Restricted Stock
Summary of Significant Accounting Policies [Line Items]
Shares issued under plan since inception (in shares) | shares					25,945
Shares fully vested (in shares) | shares					23,730
Non-vested number of shares (in shares) | shares					2,215
ACNB Corporation 2018 Omnibus Stock Incentive Plan
Summary of Significant Accounting Policies [Line Items]
Awards authorized (in shares) | shares									400,000
ACNB Corporation 2018 Omnibus Stock Incentive Plan | Restricted Stock
Summary of Significant Accounting Policies [Line Items]
Shares issued under plan since inception (in shares) | shares					16,115
Shares fully vested (in shares) | shares					5,372
Non-vested number of shares (in shares) | shares					10,743
Vesting period (in years)				2 years
Subsequent Event
Summary of Significant Accounting Policies [Line Items]
Number of loan production offices | loan_offices	3
Subsequent Event | FCBI
Summary of Significant Accounting Policies [Line Items]
ACNB’s share price of common stock for purposes of calculation | $ / shares	$ 36.43
Business Combination, Number of Directors Joining Board of Directors | director	1
Business Acquisition, Pro Forma Assets	$ 2,200,000,000
Business Acquisition, Pro Forma Deposits	1,800,000,000
Business Acquisition, Pro Forma Loans	$ 1,600,000,000
Business Acquisition, Pro Forma Number of Community Banking Offices | bank	34
Common Stock | New Windsor
Summary of Significant Accounting Policies [Line Items]
Total ACNB shares of common stock issued | shares							938,360
Common Stock | Subsequent Event | FCBI
Summary of Significant Accounting Policies [Line Items]
Exchange ratio | shares	0.9900
Total ACNB shares of common stock issued | shares	1,590,547
Real Estate
Summary of Significant Accounting Policies [Line Items]
Threshold period past due for Corporation to order updated valuation on financing receivable					90 days
Number of previous months with no updated valuation completed for Corporation to update validation					12 months
Number of maximum days of loan being classified as impaired for Corporation to order third party valuation					30 days

SUMMARY OF SIGNIFICANT ACCOUN_5

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Schedule Of Components Of The Accumulated Other Comprehensive Income, Net Of Taxes) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Loss [Line Items]
Components of accumulated other comprehensive loss	$ 189,516	$ 168,137	$ 153,966
Unrealized Losses on Securities
Accumulated Other Comprehensive Loss [Line Items]
Components of accumulated other comprehensive loss	1,261	(1,651)
Pension Liability
Accumulated Other Comprehensive Loss [Line Items]
Components of accumulated other comprehensive loss	(7,114)	(7,566)
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Loss [Line Items]
Components of accumulated other comprehensive loss	$ (5,853)	$ (9,217)	$ (7,092)

RESTRICTIONS ON CASH AND DUE _2

RESTRICTIONS ON CASH AND DUE FROM BANKS (Narrative) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Restricted Cash and Investments [Abstract]
Compensating Balance Amount	$ 2,276	$ 1,880
Average Compensating Balance Amount	$ 2,228	$ 2,073

SECURITIES (Unrealized Gain (Lo

SECURITIES (Unrealized Gain (Loss) on Investments) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Schedule of Investments [Line Items]
Securities Available for sale, Amortized Cost	$ 189,208	$ 163,862
Securities Available for sale, Gross Unrealized Gains	1,899	396
Securities Available for sale, Gross Unrealized Losses	270	2,528
Securities Available for sale, Fair Value	190,837	161,730
Securities Held to maturity, Amortized Cost	19,234	27,266
Securities Held to maturity, Gross Unrealized Gains	84	4
Securities Held to maturity, Gross Unrealized Losses	37	359
Securities held to maturity, fair value	19,281	26,911
U.S. Government and agencies
Schedule of Investments [Line Items]
Securities Available for sale, Amortized Cost	113,569	120,420
Securities Available for sale, Gross Unrealized Gains	849	142
Securities Available for sale, Gross Unrealized Losses	169	2,149
Securities Available for sale, Fair Value	114,249	118,413
Securities Held to maturity, Amortized Cost	4,000	7,000
Securities Held to maturity, Gross Unrealized Gains	8	0
Securities Held to maturity, Gross Unrealized Losses	0	69
Securities held to maturity, fair value	4,008	6,931
Mortgage-backed securities, residential
Schedule of Investments [Line Items]
Securities Available for sale, Amortized Cost	64,699	33,960
Securities Available for sale, Gross Unrealized Gains	980	194
Securities Available for sale, Gross Unrealized Losses	87	343
Securities Available for sale, Fair Value	65,592	33,811
Securities Held to maturity, Amortized Cost	15,234	20,266
Securities Held to maturity, Gross Unrealized Gains	76	4
Securities Held to maturity, Gross Unrealized Losses	37	290
Securities held to maturity, fair value	15,273	19,980
State and municipal
Schedule of Investments [Line Items]
Securities Available for sale, Amortized Cost	10,940	9,482
Securities Available for sale, Gross Unrealized Gains	70	60
Securities Available for sale, Gross Unrealized Losses	14	36
Securities Available for sale, Fair Value	$ 10,996	$ 9,506

SECURITIES (Schedule of Require

SECURITIES (Schedule of Required Fair Value Disclosures for Equity Securities) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Equity Securities, FV-NI, Realized Gain (Loss) [Roll Forward]
Fair Value at beginning of period	$ 1,839
Fair Value at end of period	2,106	$ 1,839
Accounting Standards Update 2016-01
Equity Securities, FV-NI, Realized Gain (Loss) [Roll Forward]
Fair Value at beginning of period	1,839	1,793
Unrealized Gains	267	247
Unrealized Losses	0	201
Fair Value at end of period	2,106	1,839
CRA Mutual Fund | Accounting Standards Update 2016-01
Equity Securities, FV-NI, Realized Gain (Loss) [Roll Forward]
Fair Value at beginning of period	1,012	1,044
Unrealized Gains	33	0
Unrealized Losses	0	32
Fair Value at end of period	1,045	1,012
Stock in other banks | Accounting Standards Update 2016-01
Equity Securities, FV-NI, Realized Gain (Loss) [Roll Forward]
Fair Value at beginning of period	827	749
Unrealized Gains	234	247
Unrealized Losses	0	169
Fair Value at end of period	$ 1,061	$ 827

SECURITIES (Schedule of Unreali

SECURITIES (Schedule of Unrealized Loss on Investments) (Details) $ in Thousands	Dec. 31, 2019USD ($)Security	Dec. 31, 2018USD ($)
Schedule of Investments [Line Items]
Securities Available for sale, Less than 12 Months: Fair Value	$ 19,441	$ 11,407
Securities Available for sale, Less than 12 Months: Unrealized Losses	95	139
Securities Available for sale, 12 Months or More: Fair Value	49,351	98,498
Securities Available for sale, 12 Months or More: Unrealized Losses	175	2,389
Securities Available for sale, Total: Fair Value	68,792	109,905
Securities Available for sale, Total Unrealized Loss	270	2,528
Securities Held to maturity, Less than 12 Months: Fair Value	6,587	8,383
Securities Held to maturity, Less than 12 Months: Unrealized Losses	24	84
Securities Held to maturity, 12 Months or More, Fair Value	3,161	16,592
Securities Held to maturity, 12 Months or More, Unrealized Losses	13	275
Securities Held to maturity, Total: Fair Value	9,748	24,975
Securities Held to maturity, Total Unrealized Losses	37	359
U.S. Government and agencies
Schedule of Investments [Line Items]
Securities Available for sale, Less than 12 Months: Fair Value	0	1,997
Securities Available for sale, Less than 12 Months: Unrealized Losses	0	5
Securities Available for sale, 12 Months or More: Fair Value	47,425	87,216
Securities Available for sale, 12 Months or More: Unrealized Losses	169	2,144
Securities Available for sale, Total: Fair Value	47,425	89,213
Securities Available for sale, Total Unrealized Loss	169	2,149
Securities Held to maturity, Less than 12 Months: Fair Value		2,975
Securities Held to maturity, Less than 12 Months: Unrealized Losses		25
Securities Held to maturity, 12 Months or More, Fair Value		3,956
Securities Held to maturity, 12 Months or More, Unrealized Losses		44
Securities Held to maturity, Total: Fair Value		6,931
Securities Held to maturity, Total Unrealized Losses	$ 0	69
Available for sale securities in unrealized loss positions, percentage of amortized cost (individually did not exceed)	1.00%
Available for sale securities in unrealized loss positions for 12 months or more | Security	25
Mortgage-backed securities, residential
Schedule of Investments [Line Items]
Securities Available for sale, Less than 12 Months: Fair Value	$ 16,208	9,410
Securities Available for sale, Less than 12 Months: Unrealized Losses	82	134
Securities Available for sale, 12 Months or More: Fair Value	1,424	8,586
Securities Available for sale, 12 Months or More: Unrealized Losses	5	209
Securities Available for sale, Total: Fair Value	17,632	17,996
Securities Available for sale, Total Unrealized Loss	87	343
Securities Held to maturity, Less than 12 Months: Fair Value	6,587	5,408
Securities Held to maturity, Less than 12 Months: Unrealized Losses	24	59
Securities Held to maturity, 12 Months or More, Fair Value	3,161	12,636
Securities Held to maturity, 12 Months or More, Unrealized Losses	13	231
Securities Held to maturity, Total: Fair Value	9,748	18,044
Securities Held to maturity, Total Unrealized Losses	$ 37	290
Available for sale securities in unrealized loss positions | Security	13
Available for sale securities in unrealized loss positions, percentage of amortized cost (individually did not exceed)	2.00%
Available for sale securities in unrealized loss positions for 12 months or more | Security	2
Held to maturity securities in unrealized loss positions | Security	19
Held to maturity securities in unrealized loss positions, percentage of amortized cost (individually did not exceed)	2.00%
Held to maturity securities in unrealized loss positions for 12 months or more | Security	8
State and municipal
Schedule of Investments [Line Items]
Securities Available for sale, Less than 12 Months: Fair Value	$ 3,233	0
Securities Available for sale, Less than 12 Months: Unrealized Losses	13	0
Securities Available for sale, 12 Months or More: Fair Value	502	2,696
Securities Available for sale, 12 Months or More: Unrealized Losses	1	36
Securities Available for sale, Total: Fair Value	3,735	2,696
Securities Available for sale, Total Unrealized Loss	$ 14	$ 36
Available for sale securities in unrealized loss positions | Security	6
Available for sale securities in unrealized loss positions, percentage of amortized cost (individually did not exceed)	1.00%
Available for sale securities in unrealized loss positions for 12 months or more | Security	1

SECURITIES (Investments Classif

SECURITIES (Investments Classified by Contractual Maturity Date) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Schedule of Investments [Line Items]
Available for sale Securities, Amortized Cost, 1 year or less	$ 20,926
Available for sale Securities, Fair Value, 1 year or less	20,953
Available for sale Securities, Amortized Cost, Over 1 year through 5 years	98,502
Available for sale Securities, Fair Value, Over 1 year through 5 years	99,220
Available for sale Securities, Amortized Cost, Over 5 years through 10 years	199
Available for sale Securities, Fair Value, Over 5 years through 10 years	202
Available for sale Securities, Amortized Cost, Over 10 years	4,882
Available for sale Securities, Fair Value, Over 10 years	4,870
Securities Available for sale, Amortized Cost	189,208	$ 163,862
Available for sale Securities, Fair Value	190,837	161,730
Held to maturity Securities, Amortized Cost, 1 year or less	4,000
Held to maturity Securities, Fair Value, 1 year or less	4,008
Held to maturity Securities, Amortized Cost, Over 1 year through 5 years	0
Held to maturity Securities, Fair Value, Over 1 year through 5 years	0
Held to maturity Securities, Amortized Cost, Over 5 years through 10 years	0
Held to maturity Securities, Fair Value, Over 5 years through 10 years	0
Held to maturity Securities, Amortized Cost, Over 10 years	0
Held to maturity Securities, Fair Value, Over 10 years	0
Securities Held to maturity, Amortized Cost	19,234	27,266
Investment securities held to maturity	19,281	26,911
Mortgage-backed securities, residential
Schedule of Investments [Line Items]
Available for sale Securities, Amortized Cost, without a Single Maturity Date	64,699
Available for sale Securities, Fair Value, without a Single Maturity Date	65,592
Securities Available for sale, Amortized Cost	64,699	33,960
Available for sale Securities, Fair Value	65,592	33,811
Held to maturity Securities, Debt Maturities, without Single Maturity Date, Net Carrying Amount	15,234
Held to maturity Securities, Debt Maturities, without Single Maturity Date, Fair Value	15,273
Securities Held to maturity, Amortized Cost	15,234	20,266
Investment securities held to maturity	$ 15,273	$ 19,980

SECURITIES (Narrative) (Details

SECURITIES (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Realized gross gains on sales of securities available for sale	$ 0	$ 288,000
Realized gross losses on sales of securities available for sale	0	203,000
Carrying value of securities pledged as collateral as required by law on public and trust deposits, repurchase agreements, and for other purposes	$ 162,946,000	$ 165,792,000

LOANS AND ALLOWANCE FOR LOAN _3

LOANS AND ALLOWANCE FOR LOAN LOSSES (Classes Of The Loan Portfolio Summarized By The Aggregate Risk Rating) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	$ 1,272,601	$ 1,302,465
Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	149,315	174,182
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	567,048	548,923
Commercial real estate construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	26,416	20,298
Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	408,337	434,299
Home equity lines of credit
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	108,047	110,363
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	13,438	14,400
Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	1,193,097	1,250,566
Pass | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	135,798	170,838
Pass | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	514,276	514,308
Pass | Commercial real estate construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	24,447	18,747
Pass | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	398,163	422,718
Pass | Home equity lines of credit
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	106,975	109,555
Pass | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	13,438	14,400
Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	63,433	36,588
Special Mention | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	12,623	3,036
Special Mention | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	39,801	23,191
Special Mention | Commercial real estate construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	1,969	1,551
Special Mention | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	8,368	8,388
Special Mention | Home equity lines of credit
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	672	422
Special Mention | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	0	0
Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	16,071	15,311
Substandard | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	894	308
Substandard | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	12,971	11,424
Substandard | Commercial real estate construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	0	0
Substandard | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	1,806	3,193
Substandard | Home equity lines of credit
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	400	386
Substandard | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	0	0
Doubtful
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	0	0
Doubtful | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	0	0
Doubtful | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	0	0
Doubtful | Commercial real estate construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	0	0
Doubtful | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	0	0
Doubtful | Home equity lines of credit
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	0	0
Doubtful | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	0	0
Originated Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	1,099,626	1,099,568
Originated Loans | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	145,756	169,098
Originated Loans | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	451,936	419,965
Originated Loans | Commercial real estate construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	24,177	16,306
Originated Loans | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	371,344	388,750
Originated Loans | Home equity lines of credit
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	93,082	91,275
Originated Loans | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	13,331	14,174
Originated Loans | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	1,040,290	1,062,133
Originated Loans | Pass | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	132,791	166,035
Originated Loans | Pass | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	414,077	393,987
Originated Loans | Pass | Commercial real estate construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	22,905	15,471
Originated Loans | Pass | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	364,814	381,525
Originated Loans | Pass | Home equity lines of credit
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	92,372	90,941
Originated Loans | Pass | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	13,331	14,174
Originated Loans | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	48,691	28,642
Originated Loans | Special Mention | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	12,249	2,902
Originated Loans | Special Mention | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	28,264	18,079
Originated Loans | Special Mention | Commercial real estate construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	1,272	835
Originated Loans | Special Mention | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	6,279	6,492
Originated Loans | Special Mention | Home equity lines of credit
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	627	334
Originated Loans | Special Mention | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	0	0
Originated Loans | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	10,645	8,793
Originated Loans | Substandard | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	716	161
Originated Loans | Substandard | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	9,595	7,899
Originated Loans | Substandard | Commercial real estate construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	0	0
Originated Loans | Substandard | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	251	733
Originated Loans | Substandard | Home equity lines of credit
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	83	0
Originated Loans | Substandard | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	0	0
Originated Loans | Doubtful
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	0	0
Originated Loans | Doubtful | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	0	0
Originated Loans | Doubtful | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	0	0
Originated Loans | Doubtful | Commercial real estate construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	0	0
Originated Loans | Doubtful | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	0	0
Originated Loans | Doubtful | Home equity lines of credit
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	0	0
Originated Loans | Doubtful | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	0	0
Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	172,975	202,897
Acquired Loans | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	3,559	5,084
Acquired Loans | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	115,112	128,958
Acquired Loans | Commercial real estate construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	2,239	3,992
Acquired Loans | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	36,993	45,549
Acquired Loans | Home equity lines of credit
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	14,965	19,088
Acquired Loans | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	107	226
Acquired Loans | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	152,807	188,433
Acquired Loans | Pass | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	3,007	4,803
Acquired Loans | Pass | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	100,199	120,321
Acquired Loans | Pass | Commercial real estate construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	1,542	3,276
Acquired Loans | Pass | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	33,349	41,193
Acquired Loans | Pass | Home equity lines of credit
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	14,603	18,614
Acquired Loans | Pass | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	107	226
Acquired Loans | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	14,742	7,946
Acquired Loans | Special Mention | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	374	134
Acquired Loans | Special Mention | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	11,537	5,112
Acquired Loans | Special Mention | Commercial real estate construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	697	716
Acquired Loans | Special Mention | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	2,089	1,896
Acquired Loans | Special Mention | Home equity lines of credit
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	45	88
Acquired Loans | Special Mention | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	0	0
Acquired Loans | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	5,426	6,518
Acquired Loans | Substandard | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	178	147
Acquired Loans | Substandard | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	3,376	3,525
Acquired Loans | Substandard | Commercial real estate construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	0	0
Acquired Loans | Substandard | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	1,555	2,460
Acquired Loans | Substandard | Home equity lines of credit
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	317	386
Acquired Loans | Substandard | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	0	0
Acquired Loans | Doubtful
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	0	0
Acquired Loans | Doubtful | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	0	0
Acquired Loans | Doubtful | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	0	0
Acquired Loans | Doubtful | Commercial real estate construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	0	0
Acquired Loans | Doubtful | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	0	0
Acquired Loans | Doubtful | Home equity lines of credit
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	0	0
Acquired Loans | Doubtful | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	$ 0	$ 0

LOANS AND ALLOWANCE FOR LOAN _4

LOANS AND ALLOWANCE FOR LOAN LOSSES (Schedule of Change in Accretable Yields of Acquired Loans) (Details) - Acquired Loans Accounted For Under ASC 310-30 - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Certain Loans Acquired in Transfer Accounted for as Debt Securities Accretable Yield Movement Schedule [Line Items]
Balance at beginning of period	$ 891	$ 1,234
Acquisitions of impaired loans	0	0
Reclassification from non-accretable differences	492	402
Accretion to loan interest income	(741)	(745)
Balance at end of period	$ 642	$ 891

LOANS AND ALLOWANCE FOR LOAN _5

LOANS AND ALLOWANCE FOR LOAN LOSSES (Impaired Loans By Loan Portfolio Class) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Impaired [Line Items]
Impaired Loans with Allowance, Recorded Investment	$ 65	$ 0
Impaired Loans with Allowance, Unpaid Principal Balance	65	0
Impaired Loans with Allowance, Related Allowance	42	0
Impaired Loans with No Allowance, Recorded Investment	7,637	7,300
Impaired Loans with No Allowance, Unpaid Principal Balance	7,637	7,300
Commercial and industrial
Financing Receivable, Impaired [Line Items]
Impaired Loans with Allowance, Recorded Investment	65	0
Impaired Loans with Allowance, Unpaid Principal Balance	65	0
Impaired Loans with Allowance, Related Allowance	42	0
Impaired Loans with No Allowance, Recorded Investment	0	0
Impaired Loans with No Allowance, Unpaid Principal Balance	0	0
Commercial real estate
Financing Receivable, Impaired [Line Items]
Impaired Loans with Allowance, Recorded Investment	0	0
Impaired Loans with Allowance, Unpaid Principal Balance	0	0
Impaired Loans with Allowance, Related Allowance	0	0
Impaired Loans with No Allowance, Recorded Investment	7,383	6,763
Impaired Loans with No Allowance, Unpaid Principal Balance	7,383	6,763
Commercial real estate construction
Financing Receivable, Impaired [Line Items]
Impaired Loans with Allowance, Recorded Investment	0	0
Impaired Loans with Allowance, Unpaid Principal Balance	0	0
Impaired Loans with Allowance, Related Allowance	0	0
Impaired Loans with No Allowance, Recorded Investment	0	0
Impaired Loans with No Allowance, Unpaid Principal Balance	0	0
Residential mortgage
Financing Receivable, Impaired [Line Items]
Impaired Loans with Allowance, Recorded Investment	0	0
Impaired Loans with Allowance, Unpaid Principal Balance	0	0
Impaired Loans with Allowance, Related Allowance	0	0
Impaired Loans with No Allowance, Recorded Investment	171	537
Impaired Loans with No Allowance, Unpaid Principal Balance	171	537
Home equity lines of credit
Financing Receivable, Impaired [Line Items]
Impaired Loans with Allowance, Recorded Investment	0	0
Impaired Loans with Allowance, Unpaid Principal Balance	0	0
Impaired Loans with Allowance, Related Allowance	0	0
Impaired Loans with No Allowance, Recorded Investment	83	0
Impaired Loans with No Allowance, Unpaid Principal Balance	$ 83	$ 0

LOANS AND ALLOWANCE FOR LOAN _6

LOANS AND ALLOWANCE FOR LOAN LOSSES (Average Of Impaired Loans And Related Interest Income By Loan Portfolio Class) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Impaired [Line Items]
Impaired Loans with Allowance, Average Recorded Investment	$ 27	$ 541
Impaired Loans with Allowance, Interest Income	0	0
Impaired Loans with No Allowance, Average Recorded Investment	7,082	7,720
Impaired Loans with No Allowance, Interest Income	620	260
Commercial and industrial
Financing Receivable, Impaired [Line Items]
Impaired Loans with Allowance, Average Recorded Investment	27	436
Impaired Loans with Allowance, Interest Income	0	0
Impaired Loans with No Allowance, Average Recorded Investment	0	73
Impaired Loans with No Allowance, Interest Income	0	44
Commercial real estate
Financing Receivable, Impaired [Line Items]
Impaired Loans with Allowance, Average Recorded Investment	0	0
Impaired Loans with Allowance, Interest Income	0	0
Impaired Loans with No Allowance, Average Recorded Investment	6,625	7,372
Impaired Loans with No Allowance, Interest Income	612	216
Commercial real estate construction
Financing Receivable, Impaired [Line Items]
Impaired Loans with Allowance, Average Recorded Investment	0	0
Impaired Loans with Allowance, Interest Income	0	0
Impaired Loans with No Allowance, Average Recorded Investment	0	0
Impaired Loans with No Allowance, Interest Income	0	0
Residential mortgage
Financing Receivable, Impaired [Line Items]
Impaired Loans with Allowance, Average Recorded Investment	0	75
Impaired Loans with Allowance, Interest Income	0	0
Impaired Loans with No Allowance, Average Recorded Investment	422	275
Impaired Loans with No Allowance, Interest Income	8	0
Home equity lines of credit
Financing Receivable, Impaired [Line Items]
Impaired Loans with Allowance, Average Recorded Investment	0	30
Impaired Loans with Allowance, Interest Income	0	0
Impaired Loans with No Allowance, Average Recorded Investment	35	0
Impaired Loans with No Allowance, Interest Income	$ 0	$ 0

LOANS AND ALLOWANCE FOR LOAN _7

LOANS AND ALLOWANCE FOR LOAN LOSSES (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable, Gross, Allowance, and Net [Abstract]
Interest lost on nonaccrual loans	$ 249	$ 269
Aggregate amount of loans with related parties	5,016	$ 5,858
New loans or advances extended to related parties	0
Repayments on loans or advances to related parties	$ 843

LOANS AND ALLOWANCE FOR LOAN _8

LOANS AND ALLOWANCE FOR LOAN LOSSES (Nonaccrual Loans By Classes Of The Loan Portfolio) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Past Due [Line Items]
Purchase credit impaired loans, net of unamortized fair value adjustments	$ 6,900
Total nonaccrual loans	3,919	$ 3,417
Commercial and industrial
Financing Receivable, Past Due [Line Items]
Total nonaccrual loans	65	0
Commercial real estate
Financing Receivable, Past Due [Line Items]
Total nonaccrual loans	3,600	2,880
Commercial real estate construction
Financing Receivable, Past Due [Line Items]
Total nonaccrual loans	0	0
Residential mortgage
Financing Receivable, Past Due [Line Items]
Total nonaccrual loans	171	537
Home equity lines of credit
Financing Receivable, Past Due [Line Items]
Total nonaccrual loans	$ 83	$ 0

LOANS AND ALLOWANCE FOR LOAN _9

LOANS AND ALLOWANCE FOR LOAN LOSSES (Troubled Debt Restructurings) (Details)	12 Months Ended
	Dec. 31, 2019USD ($)Contract	Dec. 31, 2018USD ($)Contract
Financing Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructurings	$ 3,974,000	$ 6,226,000
Number of troubled debt restructured loan paid off | Contract	1	1
Number of loans which has periodic late payments | Contract	1
Mortgage loans in process of foreclosure	$ 822,000	$ 661,000
Entity Loan Modification Program
Financing Receivable, Troubled Debt Restructuring [Line Items]
Proceeds from paid off troubled debt restructured loans	2,198,000	832,000
Nonaccrual
Financing Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructurings	191,000	2,343,000
Accrual
Financing Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructurings	$ 3,783,000	$ 3,883,000

LOANS AND ALLOWANCE FOR LOAN_10

LOANS AND ALLOWANCE FOR LOAN LOSSES (Loan Portfolio Summarized By The Past Due Status) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Past Due [Line Items]
Total Past Due	$ 10,145	$ 10,771
Current	1,262,456	1,291,694
Total Loans Receivable	1,272,601	1,302,465
Loans Receivable Greater than 90 Days and Accruing	1,219	3,345
Financing Receivables, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	3,815	4,555
Financing Receivables, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	3,654	1,438
Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	2,676	4,778
Commercial and industrial
Financing Receivable, Past Due [Line Items]
Total Past Due	43	129
Current	149,272	174,053
Total Loans Receivable	149,315	174,182
Loans Receivable Greater than 90 Days and Accruing	4	4
Commercial and industrial | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	16	76
Commercial and industrial | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	23	49
Commercial and industrial | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	4	4
Commercial real estate
Financing Receivable, Past Due [Line Items]
Total Past Due	4,921	2,354
Current	562,127	546,569
Total Loans Receivable	567,048	548,923
Loans Receivable Greater than 90 Days and Accruing	0	851
Commercial real estate | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	1,388	839
Commercial real estate | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	2,247	550
Commercial real estate | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	1,286	965
Commercial real estate construction
Financing Receivable, Past Due [Line Items]
Total Past Due	78	420
Current	26,338	19,878
Total Loans Receivable	26,416	20,298
Loans Receivable Greater than 90 Days and Accruing	0	77
Commercial real estate construction | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	78	343
Commercial real estate construction | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
Commercial real estate construction | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	0	77
Residential mortgage
Financing Receivable, Past Due [Line Items]
Total Past Due	4,476	7,066
Current	403,861	427,233
Total Loans Receivable	408,337	434,299
Loans Receivable Greater than 90 Days and Accruing	1,181	1,949
Residential mortgage | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	1,918	3,018
Residential mortgage | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	1,206	780
Residential mortgage | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	1,352	3,268
Home equity lines of credit
Financing Receivable, Past Due [Line Items]
Total Past Due	562	745
Current	107,485	109,618
Total Loans Receivable	108,047	110,363
Loans Receivable Greater than 90 Days and Accruing	15	464
Home equity lines of credit | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	377	243
Home equity lines of credit | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	170	38
Home equity lines of credit | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	15	464
Consumer
Financing Receivable, Past Due [Line Items]
Total Past Due	65	57
Current	13,373	14,343
Total Loans Receivable	13,438	14,400
Loans Receivable Greater than 90 Days and Accruing	19	0
Consumer | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	38	36
Consumer | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	8	21
Consumer | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	19	0
Originated Loans
Financing Receivable, Past Due [Line Items]
Total Past Due	8,045	6,693
Current	1,091,581	1,092,875
Total Loans Receivable	1,099,626	1,099,568
Loans Receivable Greater than 90 Days and Accruing	1,084	2,203
Originated Loans | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	2,223	2,659
Originated Loans | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	3,281	1,180
Originated Loans | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	2,541	2,854
Originated Loans | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Total Past Due	20	102
Current	145,736	168,996
Total Loans Receivable	145,756	169,098
Loans Receivable Greater than 90 Days and Accruing	4	4
Originated Loans | Commercial and industrial | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	16	49
Originated Loans | Commercial and industrial | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	0	49
Originated Loans | Commercial and industrial | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	4	4
Originated Loans | Commercial real estate
Financing Receivable, Past Due [Line Items]
Total Past Due	3,858	1,439
Current	448,078	418,526
Total Loans Receivable	451,936	419,965
Loans Receivable Greater than 90 Days and Accruing	0	0
Originated Loans | Commercial real estate | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	325	775
Originated Loans | Commercial real estate | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	2,247	550
Originated Loans | Commercial real estate | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	1,286	114
Originated Loans | Commercial real estate construction
Financing Receivable, Past Due [Line Items]
Total Past Due	78	0
Current	24,099	16,306
Total Loans Receivable	24,177	16,306
Loans Receivable Greater than 90 Days and Accruing	0	0
Originated Loans | Commercial real estate construction | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	78	0
Originated Loans | Commercial real estate construction | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
Originated Loans | Commercial real estate construction | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
Originated Loans | Residential mortgage
Financing Receivable, Past Due [Line Items]
Total Past Due	3,806	4,673
Current	367,538	384,077
Total Loans Receivable	371,344	388,750
Loans Receivable Greater than 90 Days and Accruing	1,061	1,824
Originated Loans | Residential mortgage | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	1,625	1,783
Originated Loans | Residential mortgage | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	949	529
Originated Loans | Residential mortgage | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	1,232	2,361
Originated Loans | Home equity lines of credit
Financing Receivable, Past Due [Line Items]
Total Past Due	218	429
Current	92,864	90,846
Total Loans Receivable	93,082	91,275
Loans Receivable Greater than 90 Days and Accruing	0	375
Originated Loans | Home equity lines of credit | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	141	16
Originated Loans | Home equity lines of credit | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	77	38
Originated Loans | Home equity lines of credit | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	0	375
Originated Loans | Consumer
Financing Receivable, Past Due [Line Items]
Total Past Due	65	50
Current	13,266	14,124
Total Loans Receivable	13,331	14,174
Loans Receivable Greater than 90 Days and Accruing	19	0
Originated Loans | Consumer | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	38	36
Originated Loans | Consumer | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	8	14
Originated Loans | Consumer | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	19	0
Acquired Loans
Financing Receivable, Past Due [Line Items]
Total Past Due	2,100	4,078
Current	170,875	198,819
Total Loans Receivable	172,975	202,897
Loans Receivable Greater than 90 Days and Accruing	135	1,142
Acquired Loans | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	1,592	1,896
Acquired Loans | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	373	258
Acquired Loans | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	135	1,924
Acquired Loans | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Total Past Due	23	27
Current	3,536	5,057
Total Loans Receivable	3,559	5,084
Loans Receivable Greater than 90 Days and Accruing	0	0
Acquired Loans | Commercial and industrial | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	0	27
Acquired Loans | Commercial and industrial | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	23	0
Acquired Loans | Commercial and industrial | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
Acquired Loans | Commercial real estate
Financing Receivable, Past Due [Line Items]
Total Past Due	1,063	915
Current	114,049	128,043
Total Loans Receivable	115,112	128,958
Loans Receivable Greater than 90 Days and Accruing	0	851
Acquired Loans | Commercial real estate | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	1,063	64
Acquired Loans | Commercial real estate | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
Acquired Loans | Commercial real estate | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	0	851
Acquired Loans | Commercial real estate construction
Financing Receivable, Past Due [Line Items]
Total Past Due	0	420
Current	2,239	3,572
Total Loans Receivable	2,239	3,992
Loans Receivable Greater than 90 Days and Accruing	0	77
Acquired Loans | Commercial real estate construction | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	0	343
Acquired Loans | Commercial real estate construction | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
Acquired Loans | Commercial real estate construction | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	0	77
Acquired Loans | Residential mortgage
Financing Receivable, Past Due [Line Items]
Total Past Due	670	2,393
Current	36,323	43,156
Total Loans Receivable	36,993	45,549
Loans Receivable Greater than 90 Days and Accruing	120	125
Acquired Loans | Residential mortgage | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	293	1,235
Acquired Loans | Residential mortgage | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	257	251
Acquired Loans | Residential mortgage | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	120	907
Acquired Loans | Home equity lines of credit
Financing Receivable, Past Due [Line Items]
Total Past Due	344	316
Current	14,621	18,772
Total Loans Receivable	14,965	19,088
Loans Receivable Greater than 90 Days and Accruing	15	89
Acquired Loans | Home equity lines of credit | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	236	227
Acquired Loans | Home equity lines of credit | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	93	0
Acquired Loans | Home equity lines of credit | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	15	89
Acquired Loans | Consumer
Financing Receivable, Past Due [Line Items]
Total Past Due	0	7
Current	107	219
Total Loans Receivable	107	226
Loans Receivable Greater than 90 Days and Accruing	0	0
Acquired Loans | Consumer | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
Acquired Loans | Consumer | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	0	7
Acquired Loans | Consumer | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	$ 0	$ 0

LOANS AND ALLOWANCE FOR LOAN_11

LOANS AND ALLOWANCE FOR LOAN LOSSES (Allowance For Loan Losses And Recorded Investment In Financing Receivables) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Loan Losses, Beginning Balance	$ 13,964,000	$ 13,976,000
Charge-offs	(917,000)	(1,810,000)
Recoveries	188,000	178,000
Provisions	600,000	1,620,000
Allowance for Loan Losses, Ending Balance	13,835,000	13,964,000
Ending balance: individually evaluated for impairment	42,000	0
Ending balance: collectively evaluated for impairment	13,793,000	13,964,000
Loans receivables, Ending Balance	1,272,601,000	1,302,465,000
Loans receivables: Ending balance: individually evaluated for impairment	7,702,000	7,300,000
Loans receivables: Ending balance: collectively evaluated for impairment	1,264,899,000	1,295,165,000
Commercial and industrial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Loan Losses, Beginning Balance	2,597,000	3,219,000
Charge-offs	(163,000)	(934,000)
Recoveries	66,000	36,000
Provisions	(100,000)	276,000
Allowance for Loan Losses, Ending Balance	2,400,000	2,597,000
Ending balance: individually evaluated for impairment	42,000	0
Ending balance: collectively evaluated for impairment	2,358,000	2,597,000
Loans receivables, Ending Balance	149,315,000	174,182,000
Loans receivables: Ending balance: individually evaluated for impairment	65,000	0
Loans receivables: Ending balance: collectively evaluated for impairment	149,250,000	174,182,000
Commercial real estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Loan Losses, Beginning Balance	6,208,000	5,228,000
Charge-offs	(78,000)	(33,000)
Recoveries	10,000	0
Provisions	553,000	1,013,000
Allowance for Loan Losses, Ending Balance	6,693,000	6,208,000
Ending balance: individually evaluated for impairment	0	0
Ending balance: collectively evaluated for impairment	6,693,000	6,208,000
Loans receivables, Ending Balance	567,048,000	548,923,000
Loans receivables: Ending balance: individually evaluated for impairment	7,383,000	6,763,000
Loans receivables: Ending balance: collectively evaluated for impairment	559,665,000	542,160,000
Commercial real estate construction
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Loan Losses, Beginning Balance	203,000	126,000
Charge-offs	0	0
Recoveries	0	103,000
Provisions	95,000	(26,000)
Allowance for Loan Losses, Ending Balance	298,000	203,000
Ending balance: individually evaluated for impairment	0	0
Ending balance: collectively evaluated for impairment	298,000	203,000
Loans receivables, Ending Balance	26,416,000	20,298,000
Loans receivables: Ending balance: individually evaluated for impairment	0	0
Loans receivables: Ending balance: collectively evaluated for impairment	26,416,000	20,298,000
Residential mortgage
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Loan Losses, Beginning Balance	2,814,000	3,226,000
Charge-offs	(173,000)	(530,000)
Recoveries	37,000	32,000
Provisions	(123,000)	86,000
Allowance for Loan Losses, Ending Balance	2,555,000	2,814,000
Ending balance: individually evaluated for impairment	0	0
Ending balance: collectively evaluated for impairment	2,555,000	2,814,000
Loans receivables, Ending Balance	408,337,000	434,299,000
Loans receivables: Ending balance: individually evaluated for impairment	171,000	537,000
Loans receivables: Ending balance: collectively evaluated for impairment	408,166,000	433,762,000
Home equity lines of credit
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Loan Losses, Beginning Balance	611,000	612,000
Charge-offs	(301,000)	(148,000)
Recoveries	12,000	0
Provisions	297,000	147,000
Allowance for Loan Losses, Ending Balance	619,000	611,000
Ending balance: individually evaluated for impairment	0	0
Ending balance: collectively evaluated for impairment	619,000	611,000
Loans receivables, Ending Balance	108,047,000	110,363,000
Loans receivables: Ending balance: individually evaluated for impairment	83,000	0
Loans receivables: Ending balance: collectively evaluated for impairment	107,964,000	110,363,000
Consumer
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Loan Losses, Beginning Balance	692,000	749,000
Charge-offs	(202,000)	(165,000)
Recoveries	63,000	7,000
Provisions	97,000	101,000
Allowance for Loan Losses, Ending Balance	650,000	692,000
Ending balance: individually evaluated for impairment	0	0
Ending balance: collectively evaluated for impairment	650,000	692,000
Loans receivables, Ending Balance	13,438,000	14,400,000
Loans receivables: Ending balance: individually evaluated for impairment	0	0
Loans receivables: Ending balance: collectively evaluated for impairment	13,438,000	14,400,000
Unallocated
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Loan Losses, Beginning Balance	839,000	816,000
Charge-offs	0	0
Recoveries	0	0
Provisions	(219,000)	23,000
Allowance for Loan Losses, Ending Balance	620,000	839,000
Ending balance: individually evaluated for impairment	0	0
Ending balance: collectively evaluated for impairment	620,000	839,000
Loans receivables, Ending Balance	0	0
Loans receivables: Ending balance: individually evaluated for impairment	0	0
Loans receivables: Ending balance: collectively evaluated for impairment	$ 0	$ 0

PREMISES AND EQUIPMENT (Table)

PREMISES AND EQUIPMENT (Table) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	$ 48,455	$ 47,130
Accumulated depreciation	(22,731)	(20,721)
Premises and equipment, net	25,724	26,409
Land
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	5,050	5,050
Buildings and improvements
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	27,915	27,509
Furniture and equipment
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	14,562	14,111
Construction in process
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	$ 928	$ 460

PREMISES AND EQUIPMENT (Narrati

PREMISES AND EQUIPMENT (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Depreciation	$ 2,076	$ 2,108

INVESTMENTS IN LOW-INCOME HOU_2

INVESTMENTS IN LOW-INCOME HOUSING PARTNERSHIPS (Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)Partnership	Dec. 31, 2018USD ($)
Real Estate Partnership Investment Subsidiaries, Net Income (Loss) before Tax [Abstract]
Number of limited partnerships in low-income properties | Partnership	3
Investments in low-income housing partnerships | $	$ 1,506	$ 1,871

DEPOSITS (Schedule Of Deposits)

DEPOSITS (Schedule Of Deposits) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Interest-bearing Deposit Liabilities [Abstract]
Non-interest bearing demand	$ 314,377	$ 302,394
Interest bearing demand	152,275	160,718
Savings	537,755	516,872
Time certificates of deposit of $250,000 or less	339,876	307,407
Time certificates of deposit greater than $250,000	67,977	60,701
Total Deposits	1,412,260	$ 1,348,092
Time certificate of deposits, threshold amount	$ 250,000

DEPOSITS (Schedule Of Maturitie

DEPOSITS (Schedule Of Maturities Of Time Certificates Of Deposits) (Details) $ in Thousands	Dec. 31, 2019USD ($)
Interest-bearing Deposit Liabilities [Abstract]
2020	$ 258,528
2021	109,470
2022	26,627
2023	6,164
2024	7,064
Time Deposits	$ 407,853

LEASE COMMITMENTS (Supplemental

LEASE COMMITMENTS (Supplemental Balance Sheet Information) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Leases [Abstract]
Operating Leases: Right of use asset	$ 3,502	$ 0
Operating Leases: Lease liabilities	$ 3,502	$ 0
Operating Leases: Weighted average remaining lease term	7 years 1 month
Operating Leases: Weighted average discount rate, Percent	5.71%

LEASE COMMITMENTS (Future Minim

LEASE COMMITMENTS (Future Minimum Rental Payments) (Details) - USD ($) $ in Thousands		Dec. 31, 2019	Dec. 31, 2018
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2020		$ 756
2021		665
2022		544
2023		480
2024		466
Thereafter		1,685
Total minimum lease payments		4,596
Amount representing interest	[1]	1,094
Present value of net minimum lease payments		$ 3,502	$ 0
[1]	Amount necessary to reduce net minimum lease payments to present value calculated at the Corporation’s incremental borrowing rate.

LEASE COMMITMENTS (Narrative) (

LEASE COMMITMENTS (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Leases [Abstract]
Rental expense	$ 883,000	$ 890,000
Total rental income	$ 94,000	$ 131,000

BORROWINGS (Schedule of Short-t

BORROWINGS (Schedule of Short-term Debt) (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Short-term Debt [Line Items]
Amount	$ 33,435,000	$ 34,648,000
Rate	0.12%	0.12%
Federal Home Loan Bank Stock	$ 3,375,000
Line of Credit Facility, Current Borrowing Capacity	29,000,000
FHLB overnight advance
Short-term Debt [Line Items]
Amount	$ 0	$ 32,000
Rate	0.00%	2.62%
Securities Sold under Agreements to Repurchase
Short-term Debt [Line Items]
Amount	$ 33,435,000	$ 34,616,000
Rate	0.12%	0.12%

BORROWINGS (Offsetting Liabilit

BORROWINGS (Offsetting Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Offsetting Liabilities [Line Items]
Fair value of securities pledged in connection with repurchase agreements	$ 34,582	$ 39,788
Commercial Customers and Government Entities
Offsetting Liabilities [Line Items]
Gross Amounts of Recognized Liabilities	33,435	34,616
Gross Amounts Offset in the Statements of Condition	0	0
Net Amounts of Liabilities Presented in the Statements of Condition	33,435	34,616
Gross Amounts Not Offset in the Statements of Condition, Financial Instruments	(33,435)	(34,616)
Gross Amounts Not Offset in the Statements of Condition, Cash Collateral Pledged	0	0
Net Amount	$ 0	$ 0

BORROWINGS (Schedule of Maturit

BORROWINGS (Schedule of Maturities of Long-term Debt) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
FHLB fixed-rate advances maturing within one year of balance sheet date, Amount	$ 20,000,000	$ 23,500,000
FHLB fixed-rate advances maturing within one year of balance sheet date, Rate	1.87%	1.73%
FHLB fixed-rate advances maturing from one to two years of balance sheet date, Amount	$ 22,716,000	$ 20,000,000
FHLB fixed-rate advances maturing from one to two years from balance sheet date, Rate	2.10%	1.87%
FHLB fixed-rate advances maturing from two to three years from balance sheet date, Amount	$ 11,000,000	$ 22,716,000
FHLB fixed-rate advances maturing from two to three years from balance sheet date, Rate	2.69%	2.10%
FHLB fixed-rate advances maturing from three to four years from balance sheet date, Amount	$ 5,000,000	$ 9,000,000
FHLB fixed-rate advances maturing from three to four years from balance sheet date, Rate	2.60%	2.70%
Long-term debt	$ 66,296,000	$ 83,516,000
Long-term debt, Rate	2.58%	2.47%
Maximum borrowings from FHLB	$ 703,056,000
Available borrowings from FHLB	$ 619,881,000
Trust preferred subordinated debt
Debt Instrument [Line Items]
Fixed rate percentage	6.39%	6.39%
Long-term debt	$ 5,000,000	$ 5,000,000
Trust preferred subordinated debt issued	$ 5,000,000
Loan payable to local bank, 4.5% | Loan payable to local bank
Debt Instrument [Line Items]
Fixed rate percentage	4.50%	4.50%
Long-term debt	$ 1,830,000	$ 2,300,000
Period of fixed interest rate	5 years
Loan payable to local bank, 5.25% | Loan payable to local bank
Debt Instrument [Line Items]
Long-term debt	$ 750,000	$ 1,000,000
Wall Street Journal Prime Rate | Loan payable to local bank, 5.25% | Loan payable to local bank
Debt Instrument [Line Items]
Basis spread on prime rate, percentage	0.25%
Effective rate, percentage	4.50%	5.25%

REGULATORY RESTRICTIONS ON DI_2

REGULATORY RESTRICTIONS ON DIVIDENDS (Narrative) (Details) $ in Thousands	Dec. 31, 2019USD ($)
Disclosure of Restrictions on Dividends, Loans and Advances Disclosure [Abstract]
Undistributed earnings of the Bank available for distribution as dividends without prior regulatory approval	$ 36,921

INCOME TAXES (Schedule of Compo

INCOME TAXES (Schedule of Components of Income Tax Expense (Benefit)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Federal:
Current	$ 5,169	$ 4,036
Deferred	122	388
Federal Income Tax Expense, Total	5,291	4,424
State:
Current	338	479
Deferred	16	69
State Income Tax Expense, Total	354	548
Income Tax Expense, Total	$ 5,645	$ 4,972

INCOME TAXES (Schedule of Recon

INCOME TAXES (Schedule of Reconciliations of the Statutory Federal Income Tax) (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Federal income tax at statutory rate	21.00%	21.00%
State income taxes, net of federal benefit	1.00%	1.60%
Tax-exempt income	(1.50%)	(1.70%)
Earnings on investment in bank-owned life insurance	(0.80%)	(0.90%)
Rehabilitation and low-income housing credits	(1.00%)	(1.10%)
Reduction of federal tax rate	0.00%	0.00%
Other	0.50%	(0.30%)
Effective Income Tax Rate, Total	19.20%	18.60%

INCOME TAXES (Narrative) (Detai

INCOME TAXES (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes Related To Net Gains On Sales Of Securities	$ 0	$ 46
Rehabilitation and Low-Income Housing Income Tax Credits	$ 281	$ 287

INCOME TAXES (Components of Def

INCOME TAXES (Components of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Allowance for loan losses	$ 2,995	$ 3,054
Available for sale securities	0	409
Accrued deferred compensation	941	884
Pension	2,033	2,207
Other-than-temporary impairment	43	43
Nonaccrual interest	194	192
Deferred director fees	664	589
Acquisition accounting	377	785
Other	604	602
Deferred tax assets: Total	7,851	8,765
Deferred tax liabilities:
Deferred loan fees	94	101
Available for sale securities	391	0
Prepaid pension benefit cost	4,154	4,289
Prepaid expenses	129	130
Accumulated depreciation	221	347
Goodwill/intangibles	1,181	1,056
Deferred tax liabilities: Total	6,170	5,923
Net Deferred Tax Asset included in Other Assets	$ 1,681	$ 2,842

FAIR VALUE MEASUREMENTS (Fair V

FAIR VALUE MEASUREMENTS (Fair Value Measurements, Recurring and Nonrecurring) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	$ 190,837	$ 161,730
Equity securities with readily determinable fair values	2,106	1,839
Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	190,837	161,730
Equity securities with readily determinable fair values	2,106	1,839
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Equity securities with readily determinable fair values	2,106	1,839
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	190,837	161,730
Equity securities with readily determinable fair values	0	0
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Equity securities with readily determinable fair values	0	0
U.S. Government and agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	114,249	118,413
Mortgage-backed securities, residential
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	65,592	33,811
State and municipal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	10,996	9,506
Fair Value, Measurements, Recurring | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	190,837	161,730
Equity securities with readily determinable fair values	2,106	1,839
Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Equity securities with readily determinable fair values	2,106	1,839
Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	190,837	161,730
Equity securities with readily determinable fair values	0	0
Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Equity securities with readily determinable fair values	0	0
Fair Value, Measurements, Recurring | U.S. Government and agencies | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	114,249	118,413
Fair Value, Measurements, Recurring | U.S. Government and agencies | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Fair Value, Measurements, Recurring | U.S. Government and agencies | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	114,249	118,413
Fair Value, Measurements, Recurring | U.S. Government and agencies | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Fair Value, Measurements, Recurring | Mortgage-backed securities, residential | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	65,592	33,811
Fair Value, Measurements, Recurring | Mortgage-backed securities, residential | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Fair Value, Measurements, Recurring | Mortgage-backed securities, residential | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	65,592	33,811
Fair Value, Measurements, Recurring | Mortgage-backed securities, residential | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Fair Value, Measurements, Recurring | State and municipal | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	10,996	9,506
Fair Value, Measurements, Recurring | State and municipal | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Fair Value, Measurements, Recurring | State and municipal | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	10,996	9,506
Fair Value, Measurements, Recurring | State and municipal | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Collateral dependent impaired loan | Nonrecurring | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure	3,806	3,883
Collateral dependent impaired loan | Nonrecurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure	0	0
Collateral dependent impaired loan | Nonrecurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure	0	0
Collateral dependent impaired loan | Nonrecurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure	$ 3,806	$ 3,883

FAIR VALUE MEASUREMENTS (Fair_2

FAIR VALUE MEASUREMENTS (Fair Value Inputs, Assets, Quantitative Information) (Details) - Nonrecurring - Fair Value Estimate - Collateral dependent impaired loan $ in Thousands	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, Fair Value Disclosure	$ 3,806	$ 3,883
Measurement Input, Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, Fair Value Measurement Input	(0.15)	(0.16)
Measurement Input, Discount Rate | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, Fair Value Measurement Input	(0.10)	(0.10)
Measurement Input, Discount Rate | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, Fair Value Measurement Input	(0.50)	(0.50)

FAIR VALUE MEASUREMENTS (Fair_3

FAIR VALUE MEASUREMENTS (Fair Value, by Balance Sheet Grouping) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Financial assets:
Interest-bearing deposits in banks	$ 97,478	$ 20,800
Equity securities available for sale	2,106	1,839
Investment securities available for sale	190,837	161,730
Investment securities held to maturity	19,281	26,911
Restricted investment in bank stocks	3,644	4,336
Carrying Amount
Financial assets:
Cash and due from banks	16,878	20,105
Interest-bearing deposits in banks	97,478	20,800
Equity securities available for sale	2,106	1,839
Investment securities available for sale	190,837	161,730
Investment securities held to maturity	19,234	27,266
Loans held for sale	2,406	408
Loans, less allowance for loan losses	1,258,766	1,288,501
Accrued interest receivable	4,368	4,545
Restricted investment in bank stocks	3,644	4,336
Financial liabilities:
Demand deposits and savings	1,004,407	979,964
Time deposits	407,853	368,128
Short-term borrowings	33,435	34,648
Long-term borrowings	61,296	78,516
Trust preferred subordinated debt	5,000	5,000
Accrued interest payable	2,676	1,364
Off-balance sheet financial instruments	0	0
Fair Value
Financial assets:
Cash and due from banks	16,878	20,105
Interest-bearing deposits in banks	97,478	20,800
Equity securities available for sale	2,106	1,839
Investment securities available for sale	190,837	161,730
Investment securities held to maturity	19,281	26,911
Loans held for sale	2,406	408
Loans, less allowance for loan losses	1,263,014	1,272,393
Accrued interest receivable	4,368	4,545
Restricted investment in bank stocks	3,644	4,336
Financial liabilities:
Demand deposits and savings	1,004,407	979,964
Time deposits	409,426	364,093
Short-term borrowings	33,435	34,648
Long-term borrowings	61,965	78,545
Trust preferred subordinated debt	4,711	4,701
Accrued interest payable	2,676	1,364
Off-balance sheet financial instruments	0	0
Level 1
Financial assets:
Cash and due from banks	9,542	8,190
Interest-bearing deposits in banks	97,478	20,800
Equity securities available for sale	2,106	1,839
Investment securities available for sale	0	0
Investment securities held to maturity	0	0
Loans held for sale	0	0
Loans, less allowance for loan losses	0	0
Accrued interest receivable	0	0
Restricted investment in bank stocks	0	0
Financial liabilities:
Demand deposits and savings	0	0
Time deposits	0	0
Short-term borrowings	0	0
Long-term borrowings	0	0
Trust preferred subordinated debt	0	0
Accrued interest payable	0	0
Off-balance sheet financial instruments	0	0
Level 2
Financial assets:
Cash and due from banks	7,336	11,915
Interest-bearing deposits in banks	0	0
Equity securities available for sale	0	0
Investment securities available for sale	190,837	161,730
Investment securities held to maturity	19,281	26,911
Loans held for sale	2,406	408
Loans, less allowance for loan losses	0	0
Accrued interest receivable	4,368	4,545
Restricted investment in bank stocks	3,644	4,336
Financial liabilities:
Demand deposits and savings	1,004,407	979,964
Time deposits	409,426	364,093
Short-term borrowings	33,435	34,648
Long-term borrowings	61,965	78,545
Trust preferred subordinated debt	4,711	4,701
Accrued interest payable	2,676	1,364
Off-balance sheet financial instruments	0	0
Level 3
Financial assets:
Cash and due from banks	0	0
Interest-bearing deposits in banks	0	0
Equity securities available for sale	0	0
Investment securities available for sale	0	0
Investment securities held to maturity	0	0
Loans held for sale	0	0
Loans, less allowance for loan losses	1,263,014	1,272,393
Accrued interest receivable	0	0
Restricted investment in bank stocks	0	0
Financial liabilities:
Demand deposits and savings	0	0
Time deposits	0	0
Short-term borrowings	0	0
Long-term borrowings	0	0
Trust preferred subordinated debt	0	0
Accrued interest payable	0	0
Off-balance sheet financial instruments	$ 0	$ 0

RETIREMENT PLANS (Schedule of B

RETIREMENT PLANS (Schedule of Benefit Plan Funded Status) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at beginning of year	$ 30,338	$ 31,547
Service cost	696	860
Interest cost	1,213	1,096
Actuarial loss (gain)	3,603	(1,944)
Benefits paid	(1,316)	(1,221)
Projected benefit obligation at end of year	34,534	30,338
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	39,680	42,439
Actual return on plan assets	5,928	(1,538)
Employer contribution	0	0
Benefits paid	(1,316)	(1,221)
Fair value of plan assets at end of year	44,292	39,680
Funded Status, included in other assets	9,758	9,342
Amounts recognized in accumulated other comprehensive income: Total net actuarial loss	9,147	9,773
Amounts recognized in accumulated other comprehensive income: Prior service cost	0	0
Total included in accumulated other comprehensive loss (pretax)	$ 9,147	$ 9,773

RETIREMENT PLANS (Estimated Cos

RETIREMENT PLANS (Estimated Costs To Be Amortized From AOCI Into Net Periodic Pension Cost) (Details) $ in Thousands	Dec. 31, 2019USD ($)
Postemployment Benefits [Abstract]
Net loss	$ 675
Prior service cost	0
Total estimated costs to be amortized from accumulated other comprehensive loss into net periodic pension cost during the next fiscal year	$ 675

RETIREMENT PLANS (Narrative) (D

RETIREMENT PLANS (Narrative) (Details)	12 Months Ended
	Dec. 31, 2019USD ($)person	Dec. 31, 2018USD ($)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Accumulated benefit obligation	$ 33,080,000	$ 29,115,000
Corporation common stock included in equity securities, percentage of total plan assets	6.00%	7.00%
Percentage of participants average monthly pay used to calculate benefit accruals	0.75%
Maximum years of benefit used to calculate benefit accruals	25 years
Number of active, vested terminated, and retired persons in the Plan | person	348
Employee contribution percentage, maximum	100.00%
Additional compensation contributed to plan	50.00%
Balance accrued included in other liabilities	$ 3,196,000	$ 2,932,000
Annual expense included in salaries and benefits expense	$ 493,000	463,000
Minimum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Percentage over employees' gross pay	3.00%
Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Percentage over employees' gross pay	5.00%
Banking Subsidiary
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer Match Percentage of Income	3.00%
Employer Contributions to and Expenses for the Plan	$ 709,000	664,000
Insurance Subsidiary
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer Contributions to and Expenses for the Plan	$ 123,000	97,000
Non-highly compensated employees | Insurance Subsidiary
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer Match Percentage of Income	6.00%
Highly compensated employees | Insurance Subsidiary
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer Match Percentage of Income	3.00%
Corporation common stock
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	$ 2,854,000	$ 2,882,000

RETIREMENT PLANS (Components Of

RETIREMENT PLANS (Components Of Net Periodic Benefit Costs (Income)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Postemployment Benefits [Abstract]
Service cost	$ 696	$ 860
Interest cost	1,213	1,096
Expected return on plan assets	(2,549)	(2,770)
Recognized net actuarial loss	850	515
Amortization of prior service cost	0	0
Net Periodic Benefit Cost (Income)	210	(299)
Net loss	224	2,365
Amortization of net loss	(850)	(515)
Amortization of prior service cost	0	0
Total recognized in other comprehensive (income) loss	(626)	1,850
Total recognized in net periodic benefit cost (income) and other comprehensive (income) loss	$ (416)	$ 1,551

RETIREMENT PLANS (Assumptions U

RETIREMENT PLANS (Assumptions Used To Determine The Benefit Obligation and Net Periodic Benefit) (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Postemployment Benefits [Abstract]
Assumptions Used Calculating Benefit Obligation: Discount rate	3.20%	4.10%
Assumptions Used Calculating Benefit Obligation: Rate of compensation increase	3.50%	3.50%
Assumptions Used Calculating Net Periodic Benefit Cost: Discount rate	4.10%	3.55%
Assumptions Used Calculating Net Periodic Benefit Cost: Expected long-term rate of return on plan assets	6.75%	6.75%
Assumptions Used Calculating Net Periodic Benefit Cost: Rate of compensation increase	3.50%	3.50%

RETIREMENT PLANS (Pension Plan

RETIREMENT PLANS (Pension Plan Weighted-Average Assets' Allocations) (Details)	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocation	100.00%	100.00%
Equity securities
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocation	45.00%	63.00%
Debt securities
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocation	42.00%	34.00%
Short-term fixed income
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocation	0.00%	0.00%
Real estate
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocation	13.00%	3.00%

RETIREMENT PLANS (Fair Value Me

RETIREMENT PLANS (Fair Value Measurements) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 44,292	$ 39,680	$ 42,439
Equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	20,098	25,150
Debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	18,516	13,376
Real estate
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5,678	1,154
Level 1 | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2,854	2,882
Level 1 | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 1 | Real estate
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 2 | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	17,244	22,268
Level 2 | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	18,516	13,376
Level 2 | Real estate
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5,678	1,154
Level 3 | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 3 | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 3 | Real estate
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 0	$ 0

RETIREMENT PLANS (Future Benefi

RETIREMENT PLANS (Future Benefit Payments) (Details) $ in Thousands	Dec. 31, 2019USD ($)
Postemployment Benefits [Abstract]
2020	$ 1,550
2021	1,670
2022	1,680
2023	1,800
2024	1,840
2025 - 2029	$ 9,480

STOCKHOLDERS' EQUITY AND REGU_3

STOCKHOLDERS' EQUITY AND REGULATORY MATTERS (Narrative) (Details) - USD ($)	Feb. 24, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Mar. 08, 2019	Mar. 20, 2018	Feb. 24, 2009
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Shares issued, Dividend Reinvestment and Stock Repurchase Plan (in shares)		17,324	15,618
Proceeds from issuance of common stock, Dividend Reinvestment and Stock Purchase Plan		$ 501,000	$ 528,000
2009 Restricted Stock Plan, number of shares authorized, but not issued (in shares)					174,055
Restricted Stock
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Shares issued under plans (in shares)		16,115	6,644
New Windsor
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Equity portion of purchase price				$ 28,620,000
Common Stock | New Windsor
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Shares of common stock issued in acquisition (in shares)				938,360
ACNB Corporation 2009 Restricted Stock Plan
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
2009 Restricted Stock plan, expiration period	10 years
Awards authorized (in shares)							200,000
ACNB Corporation 2009 Restricted Stock Plan | Restricted Stock
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Shares issued under plan since inception (in shares)		25,945
ACNB Corporation 2018 Omnibus Stock Incentive Plan
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Awards authorized (in shares)						400,000
ACNB Corporation 2018 Omnibus Stock Incentive Plan | Restricted Stock
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Shares issued under plan since inception (in shares)		16,115

STOCKHOLDERS' EQUITY AND REGU_4

STOCKHOLDERS' EQUITY AND REGULATORY MATTERS (The Actual and Required Capital Amounts and Ratios) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Corporation
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Actual, Tier 1 leverage ratio (to average assets), Amount	$ 176,403	$ 158,404
Actual, Tier 1 leverage ratio (to average assets), Ratio	10.19%	9.66%
For Capital Adequacy Purposes, Tier 1 leverage ratio (to average assets), Amount (greater than or equal to)	$ 69,239	$ 65,568
For Capital Adequacy Purposes, Tier 1 leverage ratio (to average assets), Ratio (greater than or equal to)	4.00%	4.00%
Actual, Common Tier 1 risk-based capital ratio (to risk-weighted assets), Amount	$ 176,403	$ 158,404
Actual, Common Tier 1 risk-based capital ratio (to risk-weighted assets), Ratio	14.50%	13.19%
For Capital Adequacy Purposes, Common Tier 1 risk-based capital ratio (to risk-weighted assets), Amount (greater than or equal to)	$ 54,759	$ 54,026
For Capital Adequacy Purposes, Common Tier 1 risk-based capital ratio (to risk-weighted assets), Ratio (greater than or equal to)	4.50%	4.50%
Actual, Tier 1 risk-based capital ratio (to risk-weighted assets), Amount	$ 176,403	$ 158,404
Actual, Tier 1 risk-based capital ratio (to risk-weighted assets), Ratio	14.50%	13.19%
For Capital Adequacy Purposes, Tier 1 risk-based capital ratio (to risk-weighted assets), Amount (greater than or equal to)	$ 73,012	$ 72,034
For Capital Adequacy Purposes, Tier 1 risk-based capital ratio (to risk-weighted assets), Ratio (greater than or equal to)	6.00%	6.00%
Actual, Total risk-based capital ratio (to risk-weighted assets), Amount	$ 190,319	$ 172,449
Actual, Total risk-based capital ratio (to risk-weighted assets), Ratio	15.64%	14.36%
For Capital Adequacy Purposes, Total risk-based capital ratio (to risk-weighted assets), Amount (greater than or equal to)	$ 97,349	$ 96,046
For Capital Adequacy Purposes, Total risk-based capital ratio (to risk-weighted assets), Ratio (greater than or equal to)	8.00%	8.00%
Bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Actual, Tier 1 leverage ratio (to average assets), Amount	$ 171,179	$ 154,215
Actual, Tier 1 leverage ratio (to average assets), Ratio	9.93%	9.44%
For Capital Adequacy Purposes, Tier 1 leverage ratio (to average assets), Amount (greater than or equal to)	$ 68,982	$ 65,348
For Capital Adequacy Purposes, Tier 1 leverage ratio (to average assets), Ratio (greater than or equal to)	4.00%	4.00%
To be Well Capitalized under Prompt Corrective Action Provisions, Tier 1 leverage ratio (to average assets), Amount (greater than or equal to)	$ 86,228	$ 81,686
To be Well Capitalized under Prompt Corrective Action Provisions, Tier 1 leverage ratio (to average assets), Ratio (greater than or equal to)	5.00%	5.00%
Actual, Common Tier 1 risk-based capital ratio (to risk-weighted assets), Amount	$ 171,179	$ 154,215
Actual, Common Tier 1 risk-based capital ratio (to risk-weighted assets), Ratio	14.13%	12.89%
For Capital Adequacy Purposes, Common Tier 1 risk-based capital ratio (to risk-weighted assets), Amount (greater than or equal to)	$ 54,514	$ 53,826
For Capital Adequacy Purposes, Common Tier 1 risk-based capital ratio (to risk-weighted assets), Ratio (greater than or equal to)	4.50%	4.50%
To be Well Capitalized under Prompt Corrective Action Provisions, Common Tier 1 risk-based capital ratio (to risk-weighted assets), Amount (greater than or equal to)	$ 78,742	$ 77,748
To be Well Capitalized under Prompt Corrective Action Provisions, Common Tier 1 risk-based capital ratio (to risk-weighted assets), Ratio (greater than or equal to)	6.50%	6.50%
Actual, Tier 1 risk-based capital ratio (to risk-weighted assets), Amount	$ 171,179	$ 154,215
Actual, Tier 1 risk-based capital ratio (to risk-weighted assets), Ratio	14.13%	12.89%
For Capital Adequacy Purposes, Tier 1 risk-based capital ratio (to risk-weighted assets), Amount (greater than or equal to)	$ 72,685	$ 71,768
For Capital Adequacy Purposes, Tier 1 risk-based capital ratio (to risk-weighted assets), Ratio (greater than or equal to)	6.00%	6.00%
To be Well Capitalized under Prompt Corrective Action Provisions, Tier 1 risk-based capital ratio (to risk-weighted assets), Amount (greater than or equal to)	$ 96,913	$ 95,690
To be Well Capitalized under Prompt Corrective Action Provisions, Tier 1 risk-based capital ratio (to risk-weighted assets), Ratio (greater than or equal to)	8.00%	8.00%
Actual, Total risk-based capital ratio (to risk-weighted assets), Amount	$ 185,095	$ 168,260
Actual, Total risk-based capital ratio (to risk-weighted assets), Ratio	15.28%	14.07%
For Capital Adequacy Purposes, Total risk-based capital ratio (to risk-weighted assets), Amount (greater than or equal to)	$ 96,913	$ 95,690
For Capital Adequacy Purposes, Total risk-based capital ratio (to risk-weighted assets), Ratio (greater than or equal to)	8.00%	8.00%
To be Well Capitalized under Prompt Corrective Action Provisions, Total risk-based capital ratio (to risk-weighted assets), Amount (greater than or equal to)	$ 121,142	$ 119,613
To be Well Capitalized under Prompt Corrective Action Provisions, Total risk-based capital ratio (to risk-weighted assets), Ratio (greater than or equal to)	10.00%	10.00%

FINANCIAL INSTRUMENTS WITH OF_3

FINANCIAL INSTRUMENTS WITH OFF-BALANCE SHEET RISK (Details) - USD ($)	12 Months Ended	24 Months Ended
	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Loan to value ratio requirement (no greater than)	80.00%
Commercial line of credit borrowing capacity	$ 1,500,000	$ 1,500,000
Commercial line of credit net draw amount		750,000
Commitments to Extend Credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet financial instruments	319,681,000	319,681,000	$ 279,729,000
Standby Letters of Credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet financial instruments	$ 6,584,000	$ 6,584,000	$ 3,909,000

ACNB CORPORATION (PARENT COMP_3

ACNB CORPORATION (PARENT COMPANY ONLY) FINANCIAL INFORMATION (Statements of Condition) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
ASSETS
Cash	$ 16,878	$ 20,105
Investments in low-income housing partnerships	1,506	1,871
Securities and other assets	23,138	22,314
Total Assets	1,720,253	1,647,724
LIABILITIES AND STOCKHOLDERS’ EQUITY
Long-term debt	66,296	83,516
Other liabilities	15,244	13,331
Stockholders’ equity	189,516	168,137
Total Liabilities and Stockholders’ Equity	1,720,253	1,647,724
Corporation
ASSETS
Cash	6,828	7,391
Investments in low-income housing partnerships	0	240
Securities and other assets	1,558	1,271
Receivable from banking subsidiary	812	518
Total Assets	196,360	175,460
LIABILITIES AND STOCKHOLDERS’ EQUITY
Long-term debt	6,830	7,300
Other liabilities	14	23
Stockholders’ equity	189,516	168,137
Total Liabilities and Stockholders’ Equity	196,360	175,460
Banking Subsidiary | Corporation
ASSETS
Investment	176,689	156,651
Other Subsidiaries | Corporation
ASSETS
Investment	$ 10,473	$ 9,389

ACNB CORPORATION (PARENT COMP_4

ACNB CORPORATION (PARENT COMPANY ONLY) FINANCIAL INFORMATION (Statements of Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Condensed Financial Statements, Captions [Line Items]
Gain on sale of securities	$ 0	$ 85
Other income	18,169	15,948
Income tax benefit	(5,645)	(4,972)
Net Income	23,721	21,748
Comprehensive Income	27,085	19,623
Corporation
Condensed Financial Statements, Captions [Line Items]
Dividends from banking subsidiary	6,920	6,261
Gain on sale of securities	0	47
Other income	282	35
Total Revenues	7,202	6,343
Expenses	1,739	1,421
Net income before taxes and equity in undistributed earnings of subsidiaries	5,463	4,922
Income tax benefit	501	547
Net income before equity in undistributed earnings of subsidiaries	5,964	5,469
Equity in undistributed earnings of subsidiaries	17,757	16,279
Net Income	23,721	21,748
Comprehensive Income	$ 27,085	$ 19,623

ACNB CORPORATION (PARENT COMP_5

ACNB CORPORATION (PARENT COMPANY ONLY) FINANCIAL INFORMATION (Statements of Cash Flows) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 23,721	$ 21,748
Net Cash Provided by Operating Activities	25,723	29,544
CASH FLOWS FROM INVESTING ACTIVITIES
Net Cash Provided by (Used in) Investing Activities	8,021	(53,616)
CASH FLOWS USED IN FINANCING ACTIVITIES
Proceeds from issuance of common stock	892	541
Dividends paid	(6,920)	(6,261)
Net Cash Provided by (Used in) Financing Activities	39,707	30,536
Net Increase (Decrease) in Cash and Cash Equivalents	73,451	6,464
CASH AND CASH EQUIVALENTS — BEGINNING	40,905	34,441
CASH AND CASH EQUIVALENTS — ENDING	114,356	40,905
Corporation
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	23,721	21,748
Equity in undistributed earnings of subsidiaries	(17,757)	(16,279)
Decrease (Increase) in receivable from banking subsidiary	(294)	(400)
Gain on sale of securities	0	47
Other	(57)	669
Net Cash Provided by Operating Activities	5,613	5,785
CASH FLOWS FROM INVESTING ACTIVITIES
Net Cash Provided by (Used in) Investing Activities	0	0
CASH FLOWS USED IN FINANCING ACTIVITIES
Repayments on long-term debt	(470)	(2,300)
Proceeds from issuance of common stock	1,214	727
Dividends paid	(6,920)	(6,261)
Net Cash Provided by (Used in) Financing Activities	(6,176)	(7,834)
Net Increase (Decrease) in Cash and Cash Equivalents	(563)	(2,049)
CASH AND CASH EQUIVALENTS — BEGINNING	7,391	9,440
CASH AND CASH EQUIVALENTS — ENDING	$ 6,828	$ 7,391

GOODWILL AND OTHER INTANGIBLE_2

GOODWILL AND OTHER INTANGIBLES (Carrying Value And Accumulated Amortization Of The Intangible Assets) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Jul. 01, 2017	Jan. 05, 2005
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 19,580,000	$ 19,580,000
Gross Carrying Amount of Intangible Asset	12,308,000	11,668,000
Accumulated Amortization of Intangible Asset	7,881,000	7,261,000
Amortization of Intangible Assets	$ 621,000	745,000
Core Deposits
Finite-Lived Intangible Assets [Line Items]
Intangible asset amortization life	10 years
RIG
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 6,308,000			$ 6,308,000
RIG | Customer Lists
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount of Intangible Asset	9,890,000	9,250,000
Accumulated Amortization of Intangible Asset	6,869,000	6,623,000
New Windsor
Finite-Lived Intangible Assets [Line Items]
Goodwill	13,272,000		$ 13,272,000
New Windsor | Core Deposits
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount of Intangible Asset	2,418,000	2,418,000	$ 2,418,000
Accumulated Amortization of Intangible Asset	$ 1,012,000	$ 638,000
Minimum | Customer Lists
Finite-Lived Intangible Assets [Line Items]
Intangible asset amortization life	8 years
Maximum | Customer Lists
Finite-Lived Intangible Assets [Line Items]
Intangible asset amortization life	15 years

GOODWILL AND OTHER INTANGIBLE_3

GOODWILL AND OTHER INTANGIBLES (Expected Amortization Expense) (Details) $ in Thousands	Dec. 31, 2019USD ($)
Business Combinations [Abstract]
2020	$ 590
2021	546
2022	502
2023	458
2024	406
Thereafter	$ 1,925

SEGMENT AND RELATED INFORMATI_3

SEGMENT AND RELATED INFORMATION (Segment Information) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Segment Reporting Information [Line Items]
Number of Reportable Segments	2
Net interest income and other income from external customers	$ 77,587	$ 73,043
Income before income taxes	29,366	26,720
Total assets	1,720,253	1,647,724
Capital expenditures	1,424	1,743
Banking
Segment Reporting Information [Line Items]
Net interest income and other income from external customers	71,713	67,654
Income before income taxes	27,870	25,515
Total assets	1,707,653	1,634,750
Capital expenditures	1,367	1,341
Insurance
Segment Reporting Information [Line Items]
Net interest income and other income from external customers	5,874	5,389
Income before income taxes	1,496	1,205
Total assets	12,600	12,974
Capital expenditures	$ 57	$ 402

ACQUISITION (Narrative) (Detail

ACQUISITION (Narrative) (Details)	Jan. 11, 2020USD ($)director$ / sharesshares	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Business Acquisition [Line Items]
Business Acquisition, Pro Forma Assets		$ 1,720,253,000	$ 1,647,724,000
Business Acquisition, Pro Forma Deposits		1,412,260,000	1,348,092,000
Business Acquisition, Pro Forma Loans		1,258,766,000	1,288,501,000
Merger related expenses		$ 769,000	$ 0
Subsequent Event | FCBI
Business Acquisition [Line Items]
ACNB’s share price for purposes of calculation (in dollars per share) | $ / shares	$ 36.43
Business Combination, Number of Directors Joining Board of Directors | director	1
Business Acquisition, Pro Forma Assets	$ 2,200,000,000
Business Acquisition, Pro Forma Deposits	1,800,000,000
Business Acquisition, Pro Forma Loans	$ 1,600,000,000
Subsequent Event | Common Stock | FCBI
Business Acquisition [Line Items]
Exchange ratio | shares	0.9900
Shares of common stock issued in acquisition (in shares) | shares	1,590,547

REVENUE RECOGNITION (Narrative)

REVENUE RECOGNITION (Narrative) (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Assets Held-in-trust	$ 389,000,000	$ 342,000,000