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: