$ACNB
ACNB CORP Stock $acnb

$acnb Overview Financials Valuation SEC Filings Company Website

2019 Q4 Form 10-K Financial Statement

#000071557921000012 Filed on March 05, 2021

Income Statement

Concept	2019 Q4	2019	2018 Q4
Revenue		$69.56M
YoY Change		7.85%
Cost Of Revenue
YoY Change
Gross Profit
YoY Change
Gross Profit Margin
Selling, General & Admin
YoY Change
% of Gross Profit
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$660.0K	$2.076M	$730.0K
YoY Change	-9.59%	-1.52%	8.96%
% of Gross Profit
Operating Expenses
YoY Change
Operating Profit
YoY Change
Interest Expense		$10.14M
YoY Change		37.05%
% of Operating Profit
Other Income/Expense, Net
YoY Change
Pretax Income	$6.330M	$29.37M	$6.360M
YoY Change	-0.47%	9.9%	-2.45%
Income Tax	$1.250M	$5.650M	$1.070M
% Of Pretax Income	19.75%	19.24%	16.82%
Net Earnings	$5.080M	$23.72M	$5.290M
YoY Change	-3.97%	9.07%	110.17%
Net Earnings / Revenue		34.1%
Basic Earnings Per Share		$3.36
Diluted Earnings Per Share	$717.5K	$3.360M	$751.4K
COMMON SHARES
Basic Shares Outstanding	7.075M shares	7.062M shares	7.042M shares
Diluted Shares Outstanding

Balance Sheet

Concept	2019 Q4	2019	2018 Q4
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents	$114.4M		$40.91M
Short-Term Investments
Other Short-Term Assets
YoY Change
Inventory
Prepaid Expenses
Receivables
Other Receivables
Total Short-Term Assets
YoY Change
LONG-TERM ASSETS
Property, Plant & Equipment	$25.72M	$29.20M	$26.41M
YoY Change	-2.59%	10.61%	-1.36%
Goodwill	$19.58M		$19.58M
YoY Change	0.0%		0.0%
Intangibles	$4.427M		$4.407M
YoY Change	0.45%		71.55%
Long-Term Investments
YoY Change
Other Assets
YoY Change
Total Long-Term Assets
YoY Change
TOTAL ASSETS
Total Short-Term Assets
Total Long-Term Assets
Total Assets	$1.720B	$1.720B	$1.648B
YoY Change	4.4%	4.41%	3.28%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable
YoY Change
Accrued Expenses	$3.500M	$3.500M
YoY Change
Deferred Revenue
YoY Change
Short-Term Debt	$33.44M	$33.40M	$34.65M
YoY Change	-3.5%	-3.47%	-6.12%
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities	$3.500M	$3.500M	$34.60M
YoY Change	-89.88%	-89.88%	-6.23%
LONG-TERM LIABILITIES
Long-Term Debt	$0.00	$0.00	$0.00
YoY Change
Other Long-Term Liabilities	$15.20M	$15.20M	$13.30M
YoY Change	14.29%	14.29%	15.65%
Total Long-Term Liabilities	$15.20M	$15.20M	$13.30M
YoY Change	14.29%	14.29%	15.65%
TOTAL LIABILITIES
Total Short-Term Liabilities	$3.500M	$3.500M	$34.60M
Total Long-Term Liabilities	$15.20M	$15.20M	$13.30M
Total Liabilities	$1.531B	$1.531B	$1.480B
YoY Change	3.46%	3.45%	2.64%
SHAREHOLDERS EQUITY
Retained Earnings	$138.7M		$121.9M
YoY Change	13.79%		14.65%
Common Stock	$57.43M		$56.22M
YoY Change	2.16%		1.31%
Preferred Stock
YoY Change
Treasury Stock (at cost)	$728.0K		$728.0K
YoY Change	0.0%		0.0%
Treasury Stock Shares	62.60K shares		62.60K shares
Shareholders Equity	$189.5M	$189.5M	$168.1M
YoY Change
Total Liabilities & Shareholders Equity	$1.720B	$1.720B	$1.648B
YoY Change	4.4%	4.41%	3.28%

Cashflow Statement

Concept	2019 Q4	2019	2018 Q4
OPERATING ACTIVITIES
Net Income	$5.080M	$23.72M	$5.290M
YoY Change	-3.97%	9.07%	110.17%
Depreciation, Depletion And Amortization	$660.0K	$2.076M	$730.0K
YoY Change	-9.59%	-1.52%	8.96%
Cash From Operating Activities	$5.970M	$25.72M	$8.050M
YoY Change	-25.84%	-12.93%	14.18%
INVESTING ACTIVITIES
Capital Expenditures	-$810.0K	$1.424M	-$840.0K
YoY Change	-3.57%	-18.3%	25.37%
Acquisitions		$0.00
YoY Change
Other Investing Activities	$12.28M	$9.450M	-$24.29M
YoY Change	-150.56%	-118.22%	219.61%
Cash From Investing Activities	$11.46M	$8.021M	-$25.13M
YoY Change	-145.6%	-114.96%	204.24%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net		$892.0K
YoY Change		64.88%
Debt Paid & Issued, Net		$24.22M
YoY Change		-15.9%
Cash From Financing Activities	-20.79M	$39.71M	-5.720M
YoY Change	263.46%	30.03%	-58.67%
NET CHANGE
Cash From Operating Activities	5.970M	$25.72M	8.050M
Cash From Investing Activities	11.46M	$8.021M	-25.13M
Cash From Financing Activities	-20.79M	$39.71M	-5.720M
Net Change In Cash	-3.360M	$73.45M	-22.80M
YoY Change	-85.26%	1036.31%	51.5%
FREE CASH FLOW
Cash From Operating Activities	$5.970M	$25.72M	$8.050M
Capital Expenditures	-$810.0K	$1.424M	-$840.0K
Free Cash Flow	$6.780M	$24.30M	$8.890M
YoY Change	-23.73%	-12.6%	15.16%

Facts In Submission

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CY2020	dei	Entity File Number EntityFileNumber	1-35015
CY2020	dei	Entity Registrant Name EntityRegistrantName	ACNB CORP
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CY2020	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	23-2233457
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CY2019	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	849000	USD
CY2020	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	3384000	USD
CY2019	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	2912000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	0	USD
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	0	USD
CY2020	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	0	USD
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	0	USD
CY2020	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansTax	151000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansTax	155000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansNetOfTax	524000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansNetOfTax	657000	USD
CY2020	us-gaap	Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Tax OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax	-1055000	USD
CY2019	us-gaap	Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Tax OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax	-19000	USD
CY2020	us-gaap	Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Net Of Tax OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax	-3693000	USD
CY2019	us-gaap	Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Net Of Tax OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax	-205000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	215000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	3364000	USD
CY2020	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	18609000	USD
CY2019	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	27085000	USD
CY2018Q4	us-gaap	Stockholders Equity StockholdersEquity	168137000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	23721000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	3364000	USD
CY2019	us-gaap	Stock Issued During Period Shares New Issues StockIssuedDuringPeriodSharesNewIssues	17324	shares
CY2019	us-gaap	Stock Issued During Period Value New Issues StockIssuedDuringPeriodValueNewIssues	501000	USD
CY2019	us-gaap	Stock Issued During Period Shares Employee Stock Purchase Plans StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans	16115	shares
CY2019	us-gaap	Stock Issued During Period Value Restricted Stock Award Gross StockIssuedDuringPeriodValueRestrictedStockAwardGross	391000	USD
CY2019	us-gaap	Adjustments To Additional Paid In Capital Share Based Compensation Restricted Stock Units Requisite Service Period Recognition AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationRestrictedStockUnitsRequisiteServicePeriodRecognition	322000	USD
CY2019	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	6920000	USD
CY2019Q4	us-gaap	Stockholders Equity StockholdersEquity	189516000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	18394000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	215000	USD
CY2020	us-gaap	Stock Issued During Period Shares New Issues StockIssuedDuringPeriodSharesNewIssues	1610562	shares
CY2020	us-gaap	Stock Issued During Period Value New Issues StockIssuedDuringPeriodValueNewIssues	57773000	USD
CY2020	us-gaap	Stock Issued During Period Shares Employee Stock Purchase Plans StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans	19472	shares
CY2020	us-gaap	Stock Issued During Period Value Restricted Stock Award Gross StockIssuedDuringPeriodValueRestrictedStockAwardGross	331000	USD
CY2020	us-gaap	Adjustments To Additional Paid In Capital Share Based Compensation Restricted Stock Units Requisite Service Period Recognition AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationRestrictedStockUnitsRequisiteServicePeriodRecognition	428000	USD
CY2020	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	8685000	USD
CY2020Q4	us-gaap	Stockholders Equity StockholdersEquity	257972000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	18394000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	23721000	USD
CY2020	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	2331000	USD
CY2019	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	697000	USD
CY2020	acnb	Gain Loss On Sales Of Loans Property And Foreclosed Real Estate GainLossOnSalesOfLoansPropertyAndForeclosedRealEstate	55000	USD
CY2019	acnb	Gain Loss On Sales Of Loans Property And Foreclosed Real Estate GainLossOnSalesOfLoansPropertyAndForeclosedRealEstate	87000	USD
CY2020	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	1442000	USD
CY2019	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	1160000	USD
CY2020	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	-193000	USD
CY2019	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	267000	USD
CY2020	us-gaap	Restricted Stock Expense RestrictedStockExpense	428000	USD
CY2019	us-gaap	Restricted Stock Expense RestrictedStockExpense	322000	USD
CY2020	us-gaap	Other Depreciation And Amortization OtherDepreciationAndAmortization	3651000	USD
CY2019	us-gaap	Other Depreciation And Amortization OtherDepreciationAndAmortization	2696000	USD
CY2020	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	9140000	USD
CY2019	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	600000	USD
CY2020	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-931000	USD
CY2019	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-339000	USD
CY2020	us-gaap	Increase Decrease In Accrued Interest Receivable Net IncreaseDecreaseInAccruedInterestReceivableNet	1624000	USD
CY2019	us-gaap	Increase Decrease In Accrued Interest Receivable Net IncreaseDecreaseInAccruedInterestReceivableNet	-177000	USD
CY2020	us-gaap	Increase Decrease In Interest Payable Net IncreaseDecreaseInInterestPayableNet	-1381000	USD
CY2019	us-gaap	Increase Decrease In Interest Payable Net IncreaseDecreaseInInterestPayableNet	1312000	USD
CY2019	us-gaap	Proceeds From Sale Of Loans Held For Sale ProceedsFromSaleOfLoansHeldForSale	40088000	USD
CY2020	us-gaap	Payments For Origination Of Mortgage Loans Held For Sale PaymentsForOriginationOfMortgageLoansHeldForSale	139055000	USD
CY2019	us-gaap	Payments For Origination Of Mortgage Loans Held For Sale PaymentsForOriginationOfMortgageLoansHeldForSale	41389000	USD
CY2020	us-gaap	Proceeds From Sale Of Loans Held For Sale ProceedsFromSaleOfLoansHeldForSale	136808000	USD
CY2020	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	-7270000	USD
CY2019	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	1280000	USD
CY2020	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-1038000	USD
CY2019	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	120000	USD
CY2020	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	-4419000	USD
CY2019	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	1228000	USD
CY2020	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	25470000	USD
CY2019	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	25723000	USD
CY2020	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	8940000	USD
CY2019	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	8032000	USD
CY2020	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	96474000	USD
CY2019	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	19152000	USD
CY2020	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	218032000	USD
CY2019	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	44837000	USD
CY2020	acnb	Paymentsto Acquire Equity Securities Fvni PaymentstoAcquireEquitySecuritiesFVNI	0	USD
CY2019	acnb	Paymentsto Acquire Equity Securities Fvni PaymentstoAcquireEquitySecuritiesFVNI	500000	USD
CY2020	us-gaap	Payments For Proceeds From Federal Home Loan Bank Stock PaymentsForProceedsFromFederalHomeLoanBankStock	-1843000	USD
CY2019	us-gaap	Payments For Proceeds From Federal Home Loan Bank Stock PaymentsForProceedsFromFederalHomeLoanBankStock	-692000	USD
CY2020	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	38755000	USD
CY2019	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	-28723000	USD
CY2020	us-gaap	Payments To Acquire Life Insurance Policies PaymentsToAcquireLifeInsurancePolicies	400000	USD
CY2019	us-gaap	Payments To Acquire Life Insurance Policies PaymentsToAcquireLifeInsurancePolicies	1500000	USD
CY2020	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	-35262000	USD
CY2019	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	0	USD
CY2020	acnb	Cash Paid For Insurance Agency Acquisitions Net Of Cash Acquired CashPaidForInsuranceAgencyAcquisitionsNetOfCashAcquired	542000	USD
CY2019	acnb	Cash Paid For Insurance Agency Acquisitions Net Of Cash Acquired CashPaidForInsuranceAgencyAcquisitionsNetOfCashAcquired	640000	USD
CY2020	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	1048000	USD
CY2019	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	1424000	USD
CY2020	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	392000	USD
CY2019	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	33000	USD
CY2020	us-gaap	Proceeds From Sale Of Foreclosed Assets ProceedsFromSaleOfForeclosedAssets	1018000	USD
CY2019	us-gaap	Proceeds From Sale Of Foreclosed Assets ProceedsFromSaleOfForeclosedAssets	290000	USD
CY2020	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-114848000	USD
CY2019	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	8021000	USD
CY2020	us-gaap	Increase Decrease In Demand Deposits IncreaseDecreaseInDemandDeposits	138797000	USD
CY2019	us-gaap	Increase Decrease In Demand Deposits IncreaseDecreaseInDemandDeposits	11983000	USD
CY2020	us-gaap	Increase Decrease In Time Deposits IncreaseDecreaseInTimeDeposits	260410000	USD
CY2019	us-gaap	Increase Decrease In Time Deposits IncreaseDecreaseInTimeDeposits	52185000	USD
CY2020	us-gaap	Proceeds From Repayments Of Short Term Debt ProceedsFromRepaymentsOfShortTermDebt	5029000	USD
CY2019	us-gaap	Proceeds From Repayments Of Short Term Debt ProceedsFromRepaymentsOfShortTermDebt	-1213000	USD
CY2020	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	0	USD
CY2019	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	7000000	USD
CY2020	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	22001000	USD
CY2019	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	24220000	USD
CY2020	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	8685000	USD
CY2019	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	6920000	USD
CY2020	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	824000	USD
CY2019	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	892000	USD
CY2020	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	374374000	USD
CY2019	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	39707000	USD
CY2020	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	284996000	USD
CY2019	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	73451000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	114356000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	40905000	USD
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	399352000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	114356000	USD
CY2020	us-gaap	Interest Paid Net InterestPaidNet	13603000	USD
CY2019	us-gaap	Interest Paid Net InterestPaidNet	8828000	USD
CY2020	us-gaap	Income Taxes Paid IncomeTaxesPaid	5900000	USD
CY2019	us-gaap	Income Taxes Paid IncomeTaxesPaid	5200000	USD
CY2020	acnb	Transferof Portfolio Loansand Leasesto Heldforsale Including Other Foreclosed Transactions TransferofPortfolioLoansandLeasestoHeldforsaleIncludingOtherForeclosedTransactions	135000	USD
CY2019	acnb	Transferof Portfolio Loansand Leasesto Heldforsale Including Other Foreclosed Transactions TransferofPortfolioLoansandLeasestoHeldforsaleIncludingOtherForeclosedTransactions	412000	USD
CY2020	us-gaap	Noncash Or Part Noncash Acquisition Investments Acquired1 NoncashOrPartNoncashAcquisitionInvestmentsAcquired1	22167000	USD
CY2019	us-gaap	Noncash Or Part Noncash Acquisition Investments Acquired1 NoncashOrPartNoncashAcquisitionInvestmentsAcquired1	0	USD
CY2020	us-gaap	Noncash Or Part Noncash Acquisition Accounts Receivable Acquired1 NoncashOrPartNoncashAcquisitionAccountsReceivableAcquired1	333362000	USD
CY2019	us-gaap	Noncash Or Part Noncash Acquisition Accounts Receivable Acquired1 NoncashOrPartNoncashAcquisitionAccountsReceivableAcquired1	0	USD
CY2020	us-gaap	Noncash Or Part Noncash Acquisition Fixed Assets Acquired1 NoncashOrPartNoncashAcquisitionFixedAssetsAcquired1	10959000	USD
CY2019	us-gaap	Noncash Or Part Noncash Acquisition Fixed Assets Acquired1 NoncashOrPartNoncashAcquisitionFixedAssetsAcquired1	0	USD
CY2020	acnb	Noncashor Part Noncash Acquisition Investmentin Bank Owned Life Insurance Acquired NoncashorPartNoncashAcquisitionInvestmentinBankOwnedLifeInsuranceAcquired	10896000	USD
CY2019	acnb	Noncashor Part Noncash Acquisition Investmentin Bank Owned Life Insurance Acquired NoncashorPartNoncashAcquisitionInvestmentinBankOwnedLifeInsuranceAcquired	0	USD
CY2020	acnb	Noncashor Part Noncash Acquisition Restricted Investmentsin Bank Stocks NoncashorPartNoncashAcquisitionRestrictedInvestmentsinBankStocks	1141000	USD
CY2019	acnb	Noncashor Part Noncash Acquisition Restricted Investmentsin Bank Stocks NoncashorPartNoncashAcquisitionRestrictedInvestmentsinBankStocks	0	USD
CY2020	acnb	Noncashor Part Noncash Acquisition Foreclosed Assets Heldfor Resale Acquired NoncashorPartNoncashAcquisitionForeclosedAssetsHeldforResaleAcquired	464000	USD
CY2019	acnb	Noncashor Part Noncash Acquisition Foreclosed Assets Heldfor Resale Acquired NoncashorPartNoncashAcquisitionForeclosedAssetsHeldforResaleAcquired	0	USD
CY2020	acnb	Noncashor Part Noncash Acquisition Goodwill Acquired NoncashorPartNoncashAcquisitionGoodwillAcquired	22528000	USD
CY2019	acnb	Noncashor Part Noncash Acquisition Goodwill Acquired NoncashorPartNoncashAcquisitionGoodwillAcquired	0	USD
CY2020	us-gaap	Noncash Or Part Noncash Acquisition Intangible Assets Acquired1 NoncashOrPartNoncashAcquisitionIntangibleAssetsAcquired1	3560000	USD
CY2019	us-gaap	Noncash Or Part Noncash Acquisition Intangible Assets Acquired1 NoncashOrPartNoncashAcquisitionIntangibleAssetsAcquired1	0	USD
CY2020	us-gaap	Noncash Or Part Noncash Acquisition Other Assets Acquired1 NoncashOrPartNoncashAcquisitionOtherAssetsAcquired1	3086000	USD
CY2019	us-gaap	Noncash Or Part Noncash Acquisition Other Assets Acquired1 NoncashOrPartNoncashAcquisitionOtherAssetsAcquired1	0	USD
CY2020	acnb	Noncashor Part Noncash Acquisition Noninterest Bearing Deposits Acquired NoncashorPartNoncashAcquisitionNoninterestBearingDepositsAcquired	103492000	USD
CY2019	acnb	Noncashor Part Noncash Acquisition Noninterest Bearing Deposits Acquired NoncashorPartNoncashAcquisitionNoninterestBearingDepositsAcquired	0	USD
CY2020	acnb	Noncashor Part Noncash Acquisition Interest Bearing Deposits Acquired NoncashorPartNoncashAcquisitionInterestBearingDepositsAcquired	270566000	USD
CY2019	acnb	Noncashor Part Noncash Acquisition Interest Bearing Deposits Acquired NoncashorPartNoncashAcquisitionInterestBearingDepositsAcquired	0	USD
CY2020	acnb	Noncashor Part Noncash Acquisition Trust Preferred Debentures Acquired NoncashorPartNoncashAcquisitionTrustPreferredDebenturesAcquired	6000000	USD
CY2019	acnb	Noncashor Part Noncash Acquisition Trust Preferred Debentures Acquired NoncashorPartNoncashAcquisitionTrustPreferredDebenturesAcquired	0	USD
CY2020	acnb	Noncashor Part Noncash Acquisition Long Term Debt Assumed NoncashorPartNoncashAcquisitionLongTermDebtAssumed	3450000	USD
CY2019	acnb	Noncashor Part Noncash Acquisition Long Term Debt Assumed NoncashorPartNoncashAcquisitionLongTermDebtAssumed	0	USD
CY2020	us-gaap	Noncash Or Part Noncash Acquisition Other Liabilities Assumed1 NoncashOrPartNoncashAcquisitionOtherLiabilitiesAssumed1	2637000	USD
CY2019	us-gaap	Noncash Or Part Noncash Acquisition Other Liabilities Assumed1 NoncashOrPartNoncashAcquisitionOtherLiabilitiesAssumed1	0	USD
CY2020	acnb	Noncashor Part Noncash Acquisition Noncash Financialor Equity Instrument Consideration Shares Issued Value NoncashorPartNoncashAcquisitionNoncashFinancialorEquityInstrumentConsiderationSharesIssuedValue	57000	USD
CY2019	acnb	Noncashor Part Noncash Acquisition Noncash Financialor Equity Instrument Consideration Shares Issued Value NoncashorPartNoncashAcquisitionNoncashFinancialorEquityInstrumentConsiderationSharesIssuedValue	0	USD
CY2020	acnb	Numberof Community Banking Offices Parent NumberofCommunityBankingOfficesParent	21	bank
CY2020Q4	us-gaap	Assets Held In Trust AssetsHeldInTrust	436700000	USD
CY2019Q4	us-gaap	Assets Held In Trust AssetsHeldInTrust	389000000	USD
CY2020	us-gaap	Use Of Estimates UseOfEstimates	<div style="margin-bottom:8pt;margin-top:8pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Use of Estimates</span></div><div style="margin-bottom:8pt;margin-top:8pt;text-indent:24.75pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">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.</span></div>
CY2020	us-gaap	Concentration Risk Credit Risk ConcentrationRiskCreditRisk	<div style="margin-bottom:8pt;margin-top:8pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Significant Group Concentrations of Credit Risk</span></div><div style="margin-bottom:8pt;margin-top:8pt;text-indent:24.75pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">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 $358,663,000, or 21.9%, of total loans at December 31, 2020. 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.</span></div>
CY2020	acnb	Numberof Minimum Monthsfor Corporationto Order Updated Valuation NumberofMinimumMonthsforCorporationtoOrderUpdatedValuation	P18M
CY2020	acnb	Business Combination Acquired Receivables Interest Rate Fair Value Adjustments BusinessCombinationAcquiredReceivablesInterestRateFairValueAdjustments	-2600000	USD
CY2020	acnb	Business Combination Acquired Receivables Credit Fair Value Adjustments BusinessCombinationAcquiredReceivablesCreditFairValueAdjustments	-5900000	USD
CY2020	us-gaap	Other Postretirement Benefit Expense OtherPostretirementBenefitExpense	139000	USD
CY2019	us-gaap	Other Postretirement Benefit Expense OtherPostretirementBenefitExpense	161000	USD
CY2019Q4	us-gaap	Real Estate Acquired Through Foreclosure RealEstateAcquiredThroughForeclosure	364000	USD
CY2019Q1	acnb	Sharebased Compensation Arrangementby Sharebased Payment Award Equity Instruments Other Than Options Authorizedbutnot Issued SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAuthorizedbutnotIssued	174055	shares
CY2020	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	8638654	shares
CY2019	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	7061524	shares
CY2020Q4	us-gaap	Compensating Balance Amount CompensatingBalanceAmount	0	USD
CY2019Q4	us-gaap	Compensating Balance Amount CompensatingBalanceAmount	2276000	USD
CY2020Q4	acnb	Average Compensating Balance Amount AverageCompensatingBalanceAmount	850000	USD
CY2019Q4	acnb	Average Compensating Balance Amount AverageCompensatingBalanceAmount	2228000	USD
CY2020Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	331745000	USD
CY2020Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	6248000	USD
CY2020Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	275000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	337718000	USD
CY2019Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	189208000	USD
CY2019Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	1899000	USD
CY2019Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	270000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	190837000	USD
CY2020Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	10294000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	474000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	0	USD
CY2020Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	10768000	USD
CY2019Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	19234000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	84000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	37000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	19281000	USD
CY2019Q4	acnb	Equity Securities Fvni Including Equity Securities Acquiredin Business Combination EquitySecuritiesFVNIIncludingEquitySecuritiesAcquiredinBusinessCombination	2363000	USD
CY2020	us-gaap	Equity Securities Fv Ni Unrealized Gain EquitySecuritiesFvNiUnrealizedGain	25000	USD
CY2020	us-gaap	Equity Securities Fv Ni Unrealized Loss EquitySecuritiesFvNiUnrealizedLoss	218000	USD
CY2020Q4	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	2170000	USD
CY2018Q4	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	1839000	USD
CY2019	us-gaap	Equity Securities Fv Ni Unrealized Gain EquitySecuritiesFvNiUnrealizedGain	267000	USD
CY2019	us-gaap	Equity Securities Fv Ni Unrealized Loss EquitySecuritiesFvNiUnrealizedLoss	0	USD
CY2019Q4	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	2106000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	46749000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	275000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	0	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	0	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	46749000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	275000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	19441000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	95000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	49351000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	175000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	68792000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	270000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue	0	USD
CY2020Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	0	USD
CY2020Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Twelve Months Or Longer Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue	0	USD
CY2020Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	0	USD
CY2020Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue	0	USD
CY2020Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	0	USD
CY2019Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue	6587000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	24000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Twelve Months Or Longer Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue	3161000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	13000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue	9748000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	37000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities Within One Year Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost	61958000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities Within One Year Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue	62546000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Debt Maturities Within One Year Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount	0	USD
CY2020Q4	us-gaap	Held To Maturity Securities Debt Maturities Within One Year Fair Value HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue	0	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost	37888000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	39080000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Debt Maturities After One Through Five Years Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsNetCarryingAmount	0	USD
CY2020Q4	us-gaap	Held To Maturity Securities Debt Maturities After One Through Five Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	0	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost	81927000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	82132000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Debt Maturities After Five Through Ten Years Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsNetCarryingAmount	0	USD
CY2020Q4	us-gaap	Held To Maturity Securities Debt Maturities After Five Through Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	0	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost	44645000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue	45138000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Debt Maturities After Ten Years Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsNetCarryingAmount	0	USD
CY2020Q4	us-gaap	Held To Maturity Securities Debt Maturities After Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue	0	USD
CY2020Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	331745000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	337718000	USD
CY2020Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	10294000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	10768000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Restricted DebtSecuritiesAvailableForSaleRestricted	301201000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Restricted DebtSecuritiesAvailableForSaleRestricted	162946000	USD
CY2020Q4	us-gaap	Loans And Leases Receivable Gross Carrying Amount LoansAndLeasesReceivableGrossCarryingAmount	1637784000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Gross Carrying Amount LoansAndLeasesReceivableGrossCarryingAmount	1272601000	USD
CY2020Q4	us-gaap	Impaired Financing Receivable With Related Allowance Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment	4759000	USD
CY2020Q4	us-gaap	Impaired Financing Receivable With Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance	4759000	USD
CY2020Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	1382000	USD
CY2020Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment	5962000	USD
CY2020Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance	5962000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable With Related Allowance Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment	65000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable With Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance	65000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	42000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment	7637000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance	7637000	USD
CY2020	us-gaap	Impaired Financing Receivable With Related Allowance Average Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment	2083000	USD
CY2020	us-gaap	Impaired Financing Receivable With Related Allowance Interest Income Cash Basis Method ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeCashBasisMethod	0	USD
CY2020	us-gaap	Impaired Financing Receivable With No Related Allowance Average Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment	7170000	USD
CY2020	us-gaap	Impaired Financing Receivable With No Related Allowance Interest Income Cash Basis Method ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeCashBasisMethod	303000	USD
CY2019	us-gaap	Impaired Financing Receivable With Related Allowance Average Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment	27000	USD
CY2019	us-gaap	Impaired Financing Receivable With Related Allowance Interest Income Cash Basis Method ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeCashBasisMethod	0	USD
CY2019	us-gaap	Impaired Financing Receivable With No Related Allowance Average Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment	7082000	USD
CY2019	us-gaap	Impaired Financing Receivable With No Related Allowance Interest Income Cash Basis Method ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeCashBasisMethod	620000	USD
CY2020	us-gaap	Loans And Leases Receivable Impaired Interest Lost On Nonaccrual Loans LoansAndLeasesReceivableImpairedInterestLostOnNonaccrualLoans	379000	USD
CY2019	us-gaap	Loans And Leases Receivable Impaired Interest Lost On Nonaccrual Loans LoansAndLeasesReceivableImpairedInterestLostOnNonaccrualLoans	249000	USD
CY2020Q4	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount Net CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesCarryingAmountNet	6000000.0	USD
CY2020Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	7041000	USD
CY2019Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	3919000	USD
CY2020Q4	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	3807000	USD
CY2019Q4	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	3974000	USD
CY2019	acnb	Financing Receivable Modifications Subsequent Default Numberof Contracts Paidin Full FinancingReceivableModificationsSubsequentDefaultNumberofContractsPaidinFull	1	Contract
CY2020	acnb	Financing Receivable Modifications Subsequent Default Periodic Late Payments FinancingReceivableModificationsSubsequentDefaultPeriodicLatePayments	1	Contract
CY2020Q4	us-gaap	Mortgage Loans In Process Of Foreclosure Amount MortgageLoansInProcessOfForeclosureAmount	391000	USD
CY2019Q4	us-gaap	Mortgage Loans In Process Of Foreclosure Amount MortgageLoansInProcessOfForeclosureAmount	822000	USD
CY2020Q4	us-gaap	Financing Receivable Recorded Investment Past Due FinancingReceivableRecordedInvestmentPastDue	11000000	USD
CY2020Q4	us-gaap	Financing Receivable Recorded Investment Current FinancingReceivableRecordedInvestmentCurrent	1626784000	USD
CY2020Q4	us-gaap	Loans And Leases Receivable Gross Carrying Amount LoansAndLeasesReceivableGrossCarryingAmount	1637784000	USD
CY2020Q4	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	855000	USD
CY2019Q4	us-gaap	Financing Receivable Recorded Investment Past Due FinancingReceivableRecordedInvestmentPastDue	10145000	USD
CY2019Q4	us-gaap	Financing Receivable Recorded Investment Current FinancingReceivableRecordedInvestmentCurrent	1262456000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Gross Carrying Amount LoansAndLeasesReceivableGrossCarryingAmount	1272601000	USD
CY2019Q4	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	1219000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	13835000	USD
CY2020	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	2987000	USD
CY2020	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	238000	USD
CY2020	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	9140000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	20226000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	1382000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	18844000	USD
CY2020Q4	us-gaap	Loans And Leases Receivable Gross Carrying Amount LoansAndLeasesReceivableGrossCarryingAmount	1637784000	USD
CY2020Q4	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	10721000	USD
CY2020Q4	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	1627063000	USD
CY2018Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	13964000	USD
CY2019	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	917000	USD
CY2019	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	188000	USD
CY2019	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	600000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	13835000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	42000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	13793000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Gross Carrying Amount LoansAndLeasesReceivableGrossCarryingAmount	1272601000	USD
CY2019Q4	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	7702000	USD
CY2019Q4	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	1264899000	USD
CY2019Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	48455000	USD
CY2020Q4	us-gaap	Loans And Leases Receivable Related Parties LoansAndLeasesReceivableRelatedParties	5215000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Related Parties LoansAndLeasesReceivableRelatedParties	5016000	USD
CY2020	us-gaap	Loans And Leases Receivable Related Parties Additions LoansAndLeasesReceivableRelatedPartiesAdditions	710000	USD
CY2020	us-gaap	Loans And Leases Receivable Related Parties Proceeds LoansAndLeasesReceivableRelatedPartiesProceeds	511000	USD
CY2020	acnb	Financing Receivable Expected Modifications Numberof Contracts FinancingReceivableExpectedModificationsNumberofContracts	38	Contract
CY2020Q4	acnb	Financing Receivable Expected Modifications FinancingReceivableExpectedModifications	35464419	USD
CY2020Q4	acnb	Financing Receivable Expected Modifications Percentof Loan Portfolio FinancingReceivableExpectedModificationsPercentofLoanPortfolio	0.0217
CY2020Q4	acnb	Financing Receivable Expected Modifications Percentage Of Capital FinancingReceivableExpectedModificationsPercentageOfCapital	0.1375
CY2020Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	58080000	USD
CY2020Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	25067000	USD
CY2019Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	22731000	USD
CY2020Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	33013000	USD
CY2019Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	25724000	USD
CY2020	us-gaap	Depreciation Depreciation	2387000	USD
CY2019	us-gaap	Depreciation Depreciation	2076000	USD
CY2020	acnb	Numberof Limited Partnershipsin Lowincome Properties NumberofLimitedPartnershipsinLowincomeProperties	3	Partnership
CY2020Q4	us-gaap	Investments In Affiliates Subsidiaries Associates And Joint Ventures InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures	1380000	USD
CY2019Q4	us-gaap	Investments In Affiliates Subsidiaries Associates And Joint Ventures InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures	1506000	USD
CY2020Q4	us-gaap	Noninterest Bearing Deposit Liabilities Domestic NoninterestBearingDepositLiabilitiesDomestic	556666000	USD
CY2019Q4	us-gaap	Noninterest Bearing Deposit Liabilities Domestic NoninterestBearingDepositLiabilitiesDomestic	314377000	USD
CY2020Q4	us-gaap	Interest Bearing Domestic Deposit Demand InterestBearingDomesticDepositDemand	291271000	USD
CY2019Q4	us-gaap	Interest Bearing Domestic Deposit Demand InterestBearingDomesticDepositDemand	152275000	USD
CY2020Q4	us-gaap	Deposits Savings Deposits DepositsSavingsDeposits	860930000	USD
CY2019Q4	us-gaap	Deposits Savings Deposits DepositsSavingsDeposits	537755000	USD
CY2020Q4	acnb	Time Deposits Threshold Amount TimeDepositsThresholdAmount	250000	USD
CY2020Q4	acnb	Time Deposits Lessthan250000 TimeDepositsLessthan250000	376488000	USD
CY2019Q4	acnb	Time Deposits Lessthan250000 TimeDepositsLessthan250000	339876000	USD
CY2020Q4	acnb	Time Deposits250000or More Domestic TimeDeposits250000orMoreDomestic	100170000	USD
CY2019Q4	acnb	Time Deposits250000or More Domestic TimeDeposits250000orMoreDomestic	67977000	USD
CY2020Q4	us-gaap	Deposits Deposits	2185525000	USD
CY2019Q4	us-gaap	Deposits Deposits	1412260000	USD
CY2020Q4	us-gaap	Time Deposit Maturities Year One TimeDepositMaturitiesYearOne	364184000	USD
CY2020Q4	us-gaap	Time Deposit Maturities Year Two TimeDepositMaturitiesYearTwo	76924000	USD
CY2020Q4	us-gaap	Time Deposit Maturities Year Three TimeDepositMaturitiesYearThree	14527000	USD
CY2020Q4	us-gaap	Time Deposit Maturities Year Four TimeDepositMaturitiesYearFour	10685000	USD
CY2020Q4	us-gaap	Time Deposit Maturities Year Five TimeDepositMaturitiesYearFive	10338000	USD
CY2020Q4	us-gaap	Time Deposits TimeDeposits	476658000	USD
CY2020Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	3145000	USD
CY2020Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	3138000	USD
CY2019Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	3502000	USD
CY2019Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	3502000	USD
CY2019	us-gaap	Operating Lease Lease Income OperatingLeaseLeaseIncome	94000	USD
CY2020Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P7Y
CY2020Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0563
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	805000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	646000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	560000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	540000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	518000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due After Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	1260000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	4329000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	1191000	USD
CY2020Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	3138000	USD
CY2020	us-gaap	Operating Lease Expense OperatingLeaseExpense	1024000	USD
CY2019	us-gaap	Operating Lease Expense OperatingLeaseExpense	883000	USD
CY2020	us-gaap	Operating Lease Lease Income OperatingLeaseLeaseIncome	84000	USD
CY2020Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	38464000	USD
CY2020Q4	us-gaap	Short Term Debt Weighted Average Interest Rate ShortTermDebtWeightedAverageInterestRate	0.0012
CY2019Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	33435000	USD
CY2019Q4	us-gaap	Short Term Debt Weighted Average Interest Rate ShortTermDebtWeightedAverageInterestRate	0.0012
CY2020Q4	us-gaap	Federal Home Loan Bank Stock FederalHomeLoanBankStock	2529000	USD
CY2020Q4	us-gaap	Line Of Credit Facility Current Borrowing Capacity LineOfCreditFacilityCurrentBorrowingCapacity	29000000	USD
CY2020Q4	us-gaap	Securities Sold Under Agreements To Repurchase Fair Value Of Collateral SecuritiesSoldUnderAgreementsToRepurchaseFairValueOfCollateral	54680000	USD
CY2019Q4	us-gaap	Securities Sold Under Agreements To Repurchase Fair Value Of Collateral SecuritiesSoldUnderAgreementsToRepurchaseFairValueOfCollateral	34582000	USD
CY2019Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due Within One Year Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueWithinOneYearOfBalanceSheetDate	20000000	USD
CY2019Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Average Interest Rate Of Amounts Due Within One Year Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryAverageInterestRateOfAmountsDueWithinOneYearOfBalanceSheetDate	0.0187
CY2020Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due Within One Year Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueWithinOneYearOfBalanceSheetDate	22716000	USD
CY2020Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Average Interest Rate Of Amounts Due Within One Year Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryAverageInterestRateOfAmountsDueWithinOneYearOfBalanceSheetDate	0.0210
CY2019Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due From One To Two Years Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueFromOneToTwoYearsOfBalanceSheetDate	22716000	USD
CY2019Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Average Interest Rate One To Two Years From Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryAverageInterestRateOneToTwoYearsFromBalanceSheetDate	0.0210
CY2020Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due From One To Two Years Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueFromOneToTwoYearsOfBalanceSheetDate	11000000	USD
CY2020Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Average Interest Rate One To Two Years From Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryAverageInterestRateOneToTwoYearsFromBalanceSheetDate	0.0269
CY2019Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due From Two To Three Years Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueFromTwoToThreeYearsOfBalanceSheetDate	11000000	USD
CY2019Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Average Interest Rate Two To Three Years From Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryAverageInterestRateTwoToThreeYearsFromBalanceSheetDate	0.0269
CY2020Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due From Two To Three Years Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueFromTwoToThreeYearsOfBalanceSheetDate	5000000	USD
CY2020Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Average Interest Rate Two To Three Years From Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryAverageInterestRateTwoToThreeYearsFromBalanceSheetDate	0.0260
CY2019Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due From Three To Four Years Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueFromThreeToFourYearsOfBalanceSheetDate	5000000	USD
CY2019Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Average Interest Rate Three To Four Years From Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryAverageInterestRateThreeToFourYearsFromBalanceSheetDate	0.0260
CY2020Q4	us-gaap	Long Term Debt LongTermDebt	53745000	USD
CY2020Q4	us-gaap	Debt Weighted Average Interest Rate DebtWeightedAverageInterestRate	0.0276
CY2019Q4	us-gaap	Long Term Debt LongTermDebt	66296000	USD
CY2019Q4	us-gaap	Debt Weighted Average Interest Rate DebtWeightedAverageInterestRate	0.0258
CY2020Q4	us-gaap	Federal Home Loan Bank Advances General Debt Obligations Disclosures Maximum Amount Available FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresMaximumAmountAvailable	847881000	USD
CY2020Q4	us-gaap	Federal Home Loan Bank Advances General Debt Obligations Disclosures Amount Of Available Unused Funds FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresAmountOfAvailableUnusedFunds	791915000	USD
CY2020Q4	us-gaap	Statutory Accounting Practices Statutory Amount Available For Dividend Payments Without Regulatory Approval StatutoryAccountingPracticesStatutoryAmountAvailableForDividendPaymentsWithoutRegulatoryApproval	42296000	USD
CY2020	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	4672000	USD
CY2019	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	5169000	USD
CY2020	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-1121000	USD
CY2019	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	122000	USD
CY2020	us-gaap	Federal Income Tax Expense Benefit Continuing Operations FederalIncomeTaxExpenseBenefitContinuingOperations	3551000	USD
CY2019	us-gaap	Federal Income Tax Expense Benefit Continuing Operations FederalIncomeTaxExpenseBenefitContinuingOperations	5291000	USD
CY2020	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	805000	USD
CY2019	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	338000	USD
CY2020	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	-48000	USD
CY2019	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	16000	USD
CY2020	us-gaap	State And Local Income Tax Expense Benefit Continuing Operations StateAndLocalIncomeTaxExpenseBenefitContinuingOperations	757000	USD
CY2019	us-gaap	State And Local Income Tax Expense Benefit Continuing Operations StateAndLocalIncomeTaxExpenseBenefitContinuingOperations	354000	USD
CY2020	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	4308000	USD
CY2019	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	5645000	USD
CY2020	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210
CY2019	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210
CY2020	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.026
CY2019	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.010
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Tax Exempt Income EffectiveIncomeTaxRateReconciliationTaxExemptIncome	0.020
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Tax Exempt Income EffectiveIncomeTaxRateReconciliationTaxExemptIncome	0.015
CY2020	acnb	Effective Income Tax Rate Reconciliation Earnings On Investment In Life Insurance EffectiveIncomeTaxRateReconciliationEarningsOnInvestmentInLifeInsurance	-0.013
CY2019	acnb	Effective Income Tax Rate Reconciliation Earnings On Investment In Life Insurance EffectiveIncomeTaxRateReconciliationEarningsOnInvestmentInLifeInsurance	-0.008
CY2020Q4	us-gaap	Deferred Tax Liabilities Tax Deferred Income DeferredTaxLiabilitiesTaxDeferredIncome	0	USD
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Investment EffectiveIncomeTaxRateReconciliationTaxCreditsInvestment	0.011
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Investment EffectiveIncomeTaxRateReconciliationTaxCreditsInvestment	0.010
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Change In Enacted Tax Rate EffectiveIncomeTaxRateReconciliationChangeInEnactedTaxRate	0
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Change In Enacted Tax Rate EffectiveIncomeTaxRateReconciliationChangeInEnactedTaxRate	0
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	-0.001
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	0.005
CY2020	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.191
CY2019	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.192
CY2020	us-gaap	Income Tax Credits And Adjustments IncomeTaxCreditsAndAdjustments	259000	USD
CY2019	us-gaap	Income Tax Credits And Adjustments IncomeTaxCreditsAndAdjustments	281000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Provision For Loan Losses DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsProvisionForLoanLosses	4367000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Provision For Loan Losses DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsProvisionForLoanLosses	2995000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Unrealized Losses On Availablefor Sale Securities Gross DeferredTaxAssetsUnrealizedLossesOnAvailableforSaleSecuritiesGross	0	USD
CY2019Q4	us-gaap	Deferred Tax Assets Unrealized Losses On Availablefor Sale Securities Gross DeferredTaxAssetsUnrealizedLossesOnAvailableforSaleSecuritiesGross	0	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Postretirement Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsPostretirementBenefits	1053000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Postretirement Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsPostretirementBenefits	941000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Pensions DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsPensions	2939000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Pensions DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsPensions	2033000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Deferred Income DeferredTaxAssetsDeferredIncome	634000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Deferred Income DeferredTaxAssetsDeferredIncome	0	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Impairment Losses DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsImpairmentLosses	43000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Impairment Losses DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsImpairmentLosses	43000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Other DeferredTaxAssetsTaxDeferredExpenseOther	359000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Other DeferredTaxAssetsTaxDeferredExpenseOther	194000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Accrued Liabilities DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities	766000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Accrued Liabilities DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities	664000	USD
CY2020Q4	acnb	Deferred Tax Assets Acquisition Accounting DeferredTaxAssetsAcquisitionAccounting	-501000	USD
CY2019Q4	acnb	Deferred Tax Assets Acquisition Accounting DeferredTaxAssetsAcquisitionAccounting	377000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	1747000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	604000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	11407000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	7851000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Tax Deferred Income DeferredTaxLiabilitiesTaxDeferredIncome	94000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Unrealized Gains On Trading Securities DeferredTaxLiabilitiesUnrealizedGainsOnTradingSecurities	1328000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Unrealized Gains On Trading Securities DeferredTaxLiabilitiesUnrealizedGainsOnTradingSecurities	391000	USD
CY2020Q4	acnb	Deferred Tax Liabilities Prepaid Pension Benefit Cost DeferredTaxLiabilitiesPrepaidPensionBenefitCost	4207000	USD
CY2019Q4	acnb	Deferred Tax Liabilities Prepaid Pension Benefit Cost DeferredTaxLiabilitiesPrepaidPensionBenefitCost	4154000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Prepaid Expenses DeferredTaxLiabilitiesPrepaidExpenses	130000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Prepaid Expenses DeferredTaxLiabilitiesPrepaidExpenses	129000	USD
CY2020Q4	acnb	Deferred Tax Liabilities Accumulated Depreciation DeferredTaxLiabilitiesAccumulatedDepreciation	555000	USD
CY2019Q4	acnb	Deferred Tax Liabilities Accumulated Depreciation DeferredTaxLiabilitiesAccumulatedDepreciation	221000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets DeferredTaxLiabilitiesGoodwillAndIntangibleAssets	1259000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets DeferredTaxLiabilitiesGoodwillAndIntangibleAssets	1181000	USD
CY2020Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	7479000	USD
CY2019Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	6170000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	3928000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	1681000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Benefit Obligation DefinedBenefitPlanBenefitObligation	34534000	USD
CY2018Q4	us-gaap	Defined Benefit Plan Benefit Obligation DefinedBenefitPlanBenefitObligation	30338000	USD
CY2020	us-gaap	Defined Benefit Plan Service Cost DefinedBenefitPlanServiceCost	751000	USD
CY2019	us-gaap	Defined Benefit Plan Service Cost DefinedBenefitPlanServiceCost	696000	USD
CY2020	us-gaap	Defined Benefit Plan Interest Cost DefinedBenefitPlanInterestCost	1080000	USD
CY2019	us-gaap	Defined Benefit Plan Interest Cost DefinedBenefitPlanInterestCost	1213000	USD
CY2020	us-gaap	Defined Benefit Plan Actuarial Gain Loss DefinedBenefitPlanActuarialGainLoss	-4405000	USD
CY2019	us-gaap	Defined Benefit Plan Actuarial Gain Loss DefinedBenefitPlanActuarialGainLoss	-3603000	USD
CY2020	us-gaap	Defined Benefit Plan Benefit Obligation Benefits Paid DefinedBenefitPlanBenefitObligationBenefitsPaid	1358000	USD
CY2019	us-gaap	Defined Benefit Plan Benefit Obligation Benefits Paid DefinedBenefitPlanBenefitObligationBenefitsPaid	1316000	USD
CY2020Q4	us-gaap	Defined Benefit Plan Benefit Obligation DefinedBenefitPlanBenefitObligation	39412000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Benefit Obligation DefinedBenefitPlanBenefitObligation	34534000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Fair Value Of Plan Assets DefinedBenefitPlanFairValueOfPlanAssets	44292000	USD
CY2018Q4	us-gaap	Defined Benefit Plan Fair Value Of Plan Assets DefinedBenefitPlanFairValueOfPlanAssets	39680000	USD
CY2020	us-gaap	Defined Benefit Plan Actual Return On Plan Assets DefinedBenefitPlanActualReturnOnPlanAssets	2403000	USD
CY2019	us-gaap	Defined Benefit Plan Actual Return On Plan Assets DefinedBenefitPlanActualReturnOnPlanAssets	5928000	USD
CY2020	us-gaap	Defined Benefit Plan Contributions By Employer DefinedBenefitPlanContributionsByEmployer	0	USD
CY2019	us-gaap	Defined Benefit Plan Contributions By Employer DefinedBenefitPlanContributionsByEmployer	0	USD
CY2020	us-gaap	Defined Benefit Plan Plan Assets Benefits Paid DefinedBenefitPlanPlanAssetsBenefitsPaid	1358000	USD
CY2019	us-gaap	Defined Benefit Plan Plan Assets Benefits Paid DefinedBenefitPlanPlanAssetsBenefitsPaid	1316000	USD
CY2020Q4	us-gaap	Defined Benefit Plan Fair Value Of Plan Assets DefinedBenefitPlanFairValueOfPlanAssets	45337000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Fair Value Of Plan Assets DefinedBenefitPlanFairValueOfPlanAssets	44292000	USD
CY2020Q4	us-gaap	Defined Benefit Plan Funded Status Of Plan DefinedBenefitPlanFundedStatusOfPlan	5925000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Funded Status Of Plan DefinedBenefitPlanFundedStatusOfPlan	9758000	USD
CY2020Q4	us-gaap	Defined Benefit Plan Accumulated Other Comprehensive Income Net Gains Losses Before Tax DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax	-13221000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Accumulated Other Comprehensive Income Net Gains Losses Before Tax DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax	-9147000	USD
CY2020Q4	us-gaap	Defined Benefit Plan Accumulated Other Comprehensive Income Net Prior Service Cost Credit Before Tax DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax	0	USD
CY2019Q4	us-gaap	Defined Benefit Plan Accumulated Other Comprehensive Income Net Prior Service Cost Credit Before Tax DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax	0	USD
CY2020Q4	us-gaap	Defined Benefit Plan Accumulated Other Comprehensive Income Before Tax DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax	13221000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Accumulated Other Comprehensive Income Before Tax DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax	9147000	USD
CY2020Q4	us-gaap	Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Discount Rate DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate	0.0245
CY2019Q4	us-gaap	Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Discount Rate DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate	0.0320
CY2020Q4	us-gaap	Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Rate Of Compensation Increase DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease	0.0350
CY2019Q4	us-gaap	Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Rate Of Compensation Increase DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease	0.0350
CY2020	us-gaap	Defined Benefit Plan Service Cost DefinedBenefitPlanServiceCost	751000	USD
CY2019	us-gaap	Defined Benefit Plan Service Cost DefinedBenefitPlanServiceCost	696000	USD
CY2020	us-gaap	Defined Benefit Plan Interest Cost DefinedBenefitPlanInterestCost	1080000	USD
CY2019	us-gaap	Defined Benefit Plan Interest Cost DefinedBenefitPlanInterestCost	1213000	USD
CY2020	us-gaap	Defined Benefit Plan Expected Return On Plan Assets DefinedBenefitPlanExpectedReturnOnPlanAssets	2746000	USD
CY2019	us-gaap	Defined Benefit Plan Expected Return On Plan Assets DefinedBenefitPlanExpectedReturnOnPlanAssets	2549000	USD
CY2020	us-gaap	Defined Benefit Plan Actuarial Gain Loss Immediate Recognition As Component In Net Periodic Benefit Cost Credit DefinedBenefitPlanActuarialGainLossImmediateRecognitionAsComponentInNetPeriodicBenefitCostCredit	-675000	USD
CY2019	us-gaap	Defined Benefit Plan Actuarial Gain Loss Immediate Recognition As Component In Net Periodic Benefit Cost Credit DefinedBenefitPlanActuarialGainLossImmediateRecognitionAsComponentInNetPeriodicBenefitCostCredit	-850000	USD
CY2020	us-gaap	Defined Benefit Plan Amortization Of Prior Service Cost Credit DefinedBenefitPlanAmortizationOfPriorServiceCostCredit	0	USD
CY2019	us-gaap	Defined Benefit Plan Amortization Of Prior Service Cost Credit DefinedBenefitPlanAmortizationOfPriorServiceCostCredit	0	USD
CY2020	us-gaap	Defined Benefit Plan Net Periodic Benefit Cost DefinedBenefitPlanNetPeriodicBenefitCost	-240000	USD
CY2019	us-gaap	Defined Benefit Plan Net Periodic Benefit Cost DefinedBenefitPlanNetPeriodicBenefitCost	210000	USD
CY2020	us-gaap	Defined Benefit Plan Amounts Recognized In Other Comprehensive Income Loss Net Gain Loss Before Tax DefinedBenefitPlanAmountsRecognizedInOtherComprehensiveIncomeLossNetGainLossBeforeTax	4749000	USD
CY2019	us-gaap	Defined Benefit Plan Amounts Recognized In Other Comprehensive Income Loss Net Gain Loss Before Tax DefinedBenefitPlanAmountsRecognizedInOtherComprehensiveIncomeLossNetGainLossBeforeTax	224000	USD
CY2020	us-gaap	Defined Benefit Plan Amortization Of Gains Losses DefinedBenefitPlanAmortizationOfGainsLosses	-675000	USD
CY2019	us-gaap	Defined Benefit Plan Amortization Of Gains Losses DefinedBenefitPlanAmortizationOfGainsLosses	-850000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Amortization Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Before Tax OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditBeforeTax	0	USD
CY2019	us-gaap	Other Comprehensive Income Loss Amortization Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Before Tax OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditBeforeTax	0	USD
CY2020	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax	-4074000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax	626000	USD
CY2020	us-gaap	Amount Recognized In Net Periodic Benefit Cost And Other Comprehensive Income Loss Before Tax AmountRecognizedInNetPeriodicBenefitCostAndOtherComprehensiveIncomeLossBeforeTax	3834000	USD
CY2019	us-gaap	Amount Recognized In Net Periodic Benefit Cost And Other Comprehensive Income Loss Before Tax AmountRecognizedInNetPeriodicBenefitCostAndOtherComprehensiveIncomeLossBeforeTax	-416000	USD
CY2019	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Discount Rate DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate	0.0410
CY2020	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Expected Long Term Return On Assets DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets	0.0675
CY2020	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Discount Rate DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate	0.0320
CY2019	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Expected Long Term Return On Assets DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets	0.0675
CY2020	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Rate Of Compensation Increase DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease	0.0350
CY2019	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Rate Of Compensation Increase DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease	0.0350
CY2020Q4	us-gaap	Defined Benefit Plan Benefit Obligation DefinedBenefitPlanBenefitObligation	39412000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Benefit Obligation DefinedBenefitPlanBenefitObligation	34534000	USD
CY2020Q4	us-gaap	Defined Benefit Plan Accumulated Benefit Obligation DefinedBenefitPlanAccumulatedBenefitObligation	37522000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Accumulated Benefit Obligation DefinedBenefitPlanAccumulatedBenefitObligation	33080000	USD
CY2020Q4	us-gaap	Defined Benefit Plan Fair Value Of Plan Assets DefinedBenefitPlanFairValueOfPlanAssets	45337000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Fair Value Of Plan Assets DefinedBenefitPlanFairValueOfPlanAssets	44292000	USD
CY2020	acnb	Defined Benefit Plan Percentageof Participants Average Monthly Pay Usedto Calculate Benefit Accruals DefinedBenefitPlanPercentageofParticipantsAverageMonthlyPayUsedtoCalculateBenefitAccruals	0.0075
CY2020	acnb	Defined Benefit Plan Maximum Yearsof Benefit Usedto Calculate Benefit Accruals DefinedBenefitPlanMaximumYearsofBenefitUsedtoCalculateBenefitAccruals	P25Y
CY2020Q4	acnb	Defined Benefit Plan Numberof Active Vested Terminatedand Retired Persons DefinedBenefitPlanNumberofActiveVestedTerminatedandRetiredPersons	347	person
CY2020	acnb	Defined Benefit Plan Benefit Obligation Actuarial Gain Loss Mortality Assumptions DefinedBenefitPlanBenefitObligationActuarialGainLossMortalityAssumptions	-3699000	USD
CY2020Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Next Twelve Months DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths	1730000	USD
CY2020Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Year Two DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo	1720000	USD
CY2020Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Year Three DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree	1840000	USD
CY2020Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Year Four DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour	1890000	USD
CY2020Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Year Five DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive	1920000	USD
CY2020Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Five Fiscal Years Thereafter DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter	9800000	USD
CY2020Q4	us-gaap	Defined Benefit Plan Weighted Average Asset Allocations DefinedBenefitPlanWeightedAverageAssetAllocations	1
CY2019Q4	us-gaap	Defined Benefit Plan Weighted Average Asset Allocations DefinedBenefitPlanWeightedAverageAssetAllocations	1
CY2020	acnb	Corporation Common Stock Included In Equity Securities Percentage Of Total Plan Assets CorporationCommonStockIncludedInEquitySecuritiesPercentageOfTotalPlanAssets	0.04
CY2019	acnb	Corporation Common Stock Included In Equity Securities Percentage Of Total Plan Assets CorporationCommonStockIncludedInEquitySecuritiesPercentageOfTotalPlanAssets	0.06
CY2020	us-gaap	Defined Contribution Plan Maximum Annual Contributions Per Employee Percent DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent	1
CY2020	us-gaap	Defined Contribution Plan Maximum Annual Contributions Per Employee Percent DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent	1
CY2020	acnb	Defined Contribution Plan Employee Matching Contribution Additional Percentof Employees Compensation Contributedto Plan DefinedContributionPlanEmployeeMatchingContributionAdditionalPercentofEmployeesCompensationContributedtoPlan	0.50
CY2020	acnb	Defined Contribution Plan Employee Matching Contribution Percentage Over Employees Gross Pay DefinedContributionPlanEmployeeMatchingContributionPercentageOverEmployeesGrossPay	0.02
CY2020Q4	us-gaap	Pension And Other Postretirement Defined Benefit Plans Liabilities Current And Noncurrent PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesCurrentAndNoncurrent	3491000	USD
CY2019Q4	us-gaap	Pension And Other Postretirement Defined Benefit Plans Liabilities Current And Noncurrent PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesCurrentAndNoncurrent	3196000	USD
CY2020	us-gaap	Defined Benefit Plan Cost Of Providing Special Or Contractual Termination Benefit Recognized During Period DefinedBenefitPlanCostOfProvidingSpecialOrContractualTerminationBenefitRecognizedDuringPeriod	524000	USD
CY2019	us-gaap	Defined Benefit Plan Cost Of Providing Special Or Contractual Termination Benefit Recognized During Period DefinedBenefitPlanCostOfProvidingSpecialOrContractualTerminationBenefitRecognizedDuringPeriod	493000	USD
CY2020	us-gaap	Stock Issued During Period Shares Dividend Reinvestment Plan StockIssuedDuringPeriodSharesDividendReinvestmentPlan	20015	shares
CY2020	us-gaap	Proceeds From Issuance Of Common Stock Dividend Reinvestment Plan ProceedsFromIssuanceOfCommonStockDividendReinvestmentPlan	493000	USD
CY2019	us-gaap	Stock Issued During Period Shares Dividend Reinvestment Plan StockIssuedDuringPeriodSharesDividendReinvestmentPlan	17324	shares
CY2019	us-gaap	Proceeds From Issuance Of Common Stock Dividend Reinvestment Plan ProceedsFromIssuanceOfCommonStockDividendReinvestmentPlan	501000	USD
CY2019Q1	acnb	Sharebased Compensation Arrangementby Sharebased Payment Award Equity Instruments Other Than Options Authorizedbutnot Issued SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAuthorizedbutnotIssued	174055	shares
CY2020	acnb	Loansand Leases Receivable Loanto Value Ratio Requirement LoansandLeasesReceivableLoantoValueRatioRequirement	0.80
CY2020Q4	us-gaap	Line Of Credit Facility Maximum Borrowing Capacity LineOfCreditFacilityMaximumBorrowingCapacity	1500000	USD
CY2020	us-gaap	Proceeds From Lines Of Credit ProceedsFromLinesOfCredit	0	USD
CY2020	us-gaap	Loss Contingency Disclosures LossContingencyDisclosures	CONTINGENCIESThe 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.
CY2020Q4	us-gaap	Goodwill Goodwill	42108000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	7265000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense After Year Five FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive	2561000	USD
CY2020	us-gaap	Number Of Reportable Segments NumberOfReportableSegments	2
CY2020Q4	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	16406000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	9141000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	12308000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	7881000	USD
CY2020	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	1264000	USD
CY2019	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	621000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Next Twelve Months FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths	1164000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Two FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo	1056000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Three FiniteLivedIntangibleAssetsAmortizationExpenseYearThree	947000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Four FiniteLivedIntangibleAssetsAmortizationExpenseYearFour	830000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Five FiniteLivedIntangibleAssetsAmortizationExpenseYearFive	707000	USD
CY2020	acnb	Net Interest Income And Other Income From External Customers NetInterestIncomeAndOtherIncomeFromExternalCustomers	93002000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	22702000	USD
CY2020Q4	us-gaap	Assets Assets	2555362000	USD
CY2020	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	1048000	USD
CY2019	acnb	Net Interest Income And Other Income From External Customers NetInterestIncomeAndOtherIncomeFromExternalCustomers	77587000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	29366000	USD
CY2019Q4	us-gaap	Assets Assets	1720253000	USD
CY2019	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	1424000	USD
CY2020Q1	us-gaap	Business Combination Acquired Receivables Gross Contractual Amount BusinessCombinationAcquiredReceivablesGrossContractualAmount	339577000	USD
CY2020Q1	acnb	Business Combination Acquired Receivables Interest Rate Fair Value Adjustments BusinessCombinationAcquiredReceivablesInterestRateFairValueAdjustments	2600000	USD
CY2020Q1	acnb	Business Combination Acquired Receivables Credit Fair Value Adjustments BusinessCombinationAcquiredReceivablesCreditFairValueAdjustments	5300000	USD
CY2020Q1	us-gaap	Liabilities Fair Value Adjustment LiabilitiesFairValueAdjustment	854000	USD
	us-gaap	Business Acquisitions Pro Forma Revenue BusinessAcquisitionsProFormaRevenue	72281000	USD
	us-gaap	Business Acquisitions Pro Forma Net Income Loss BusinessAcquisitionsProFormaNetIncomeLoss	22138000	USD
CY2020	us-gaap	Business Combination Integration Related Costs BusinessCombinationIntegrationRelatedCosts	6000000.0	USD
CY2020Q4	us-gaap	Assets Held In Trust AssetsHeldInTrust	436700000	USD
CY2019Q4	us-gaap	Assets Held In Trust AssetsHeldInTrust	389000000	USD

Files In Submission

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0000715579-21-000012.txt	Edgar Link	pending
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$ACNB
ACNB CORP Stock $acnb

2019 Q4 Form 10-K Financial Statement

#000071557921000012 Filed on March 05, 2021

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$ACNB ACNB CORP Stock $acnb

2019 Q4 Form 10-K Financial Statement

#000071557921000012 Filed on March 05, 2021

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$ACNB
ACNB CORP Stock $acnb