XML 60 R48.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Securities - Narrative (Details) | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2018 USD ($) Security | Sep. 30, 2018 USD ($) Security | Dec. 31, 2017 USD ($)
Debt Securities, Available-for-sale [Line Items] |  |  |
Gross gains on sales of securities available for sale | $ | $ 31,000 | $ 44,000 |
Carrying value of securities pledged as collateral as required by law on public and trust deposits, repurchase agreements, and for other purposes | $ | $ 181,820,000 | $ 181,820,000 | $ 157,601,000
U.S. Government and agencies |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Available for sale securities in unrealized loss positions | 74 | 74 |
Available for sale securities in unrealized loss positions, percentage of amortized cost (individually did not exceed) | 7.00% | 7.00% |
Available for sale securities in unrealized loss positions for 12 months or more | 50 | 50 |
Schedule of Held-to-maturity Securities [Line Items] |  |  |
Held to maturity securities in unrealized loss positions | 7 | 7 |
Held to maturity securities in unrealized loss positions, percentage of amortized cost (individually did not exceed) | 2.00% | 2.00% |
Held to maturity securities in unrealized loss positions for 12 months or more | 5 | 5 |
Mortgage-backed securities, residential |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Available for sale securities in unrealized loss positions | 38 | 38 |
Available for sale securities in unrealized loss positions, percentage of amortized cost (individually did not exceed) | 5.00% | 5.00% |
Available for sale securities in unrealized loss positions for 12 months or more | 7 | 7 |
Schedule of Held-to-maturity Securities [Line Items] |  |  |
Held to maturity securities in unrealized loss positions | 34 | 34 |
Held to maturity securities in unrealized loss positions, percentage of amortized cost (individually did not exceed) | 5.00% | 5.00% |
Held to maturity securities in unrealized loss positions for 12 months or more | 13 | 13 |
State and municipal |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Available for sale securities in unrealized loss positions | 12 | 12 |
Available for sale securities in unrealized loss positions, percentage of amortized cost (individually did not exceed) | 6.00% | 6.00% |
Available for sale securities in unrealized loss positions for 12 months or more | 8 | 8 |

X
- Definition Available-for-sale, Securities in Unrealized Loss Positions, Unrealized Losses as Percentage of Amortized Cost + References No definition available. + Details
Name: | acnb_AvailableforsaleSecuritiesinUnrealizedLossPositionsUnrealizedLossesasPercentageofAmortizedCost
Namespace Prefix: | acnb_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Held-to-maturity, Number of Securities in Continuous Loss Positions for 12 Months or More + References No definition available. + Details
Name: | acnb_HeldtomaturityNumberofSecuritiesinContinuousLossPositionsfor12MonthsorMore
Namespace Prefix: | acnb_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Held-to-maturity, Securities in Unrealized Loss Positions, Unrealized Losses as Percentage of Amortized Cost + References No definition available. + Details
Name: | acnb_HeldtomaturitySecuritiesinUnrealizedLossPositionsUnrealizedLossesasPercentageofAmortizedCost
Namespace Prefix: | acnb_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of investment positions in available-for-sale investments in a continuous unrealized loss position for which an other-than-temporary impairment (OTTI) has not been recognized in the income statement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (b)(3) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27290-111563 + Details
Name: | us-gaap_AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of investment positions in available-for-sale investments that have been in a continuous unrealized loss position for greater than or equal to a year for which an other-than-temporary impairment (OTTI) has not been recognized in the income statement. + References No definition available. + Details
Name: | us-gaap_AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositionsGreaterThanOrEqualToOneYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of realized gain on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27357-111563 + Details
Name: | us-gaap_DebtSecuritiesAvailableForSaleRealizedGain
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of restricted investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 30 -Section 50 -Paragraph 1A -Subparagraph (b)(1)(i) -URI http://asc.fasb.org/extlink&oid=109249958&loc=SL6224234-111729 + Details
Name: | us-gaap_DebtSecuritiesAvailableForSaleRestricted
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Disclosure regarding factors used to determine that the impairment of securities categorized as held-to-maturity where cost exceeds fair value is not an other than temporary impairment (OTTI). This item contains disclosure of the number of investment positions in the held-to-maturity investments determined to be temporarily impaired. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (b)(3) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27290-111563 + Details
Name: | us-gaap_HeldToMaturitySecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions
Namespace Prefix: | us-gaap_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_ScheduleOfHeldToMaturitySecuritiesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_USTreasuryAndGovernmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_ResidentialMortgageBackedSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_USStatesAndPoliticalSubdivisionsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |