Percent of post transaction outstanding shares of the acquiring entity issued or issuable to acquire entity.

No definition available.

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- Definition

Business Combination, Acquired Receivables, Credit Fair Value Adjustments

+ References

No definition available.

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- Definition

Business Combination, Acquired Receivables, Interest Rate Fair Value Adjustments

+ References

No definition available.

+ Details

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- Definition

Amount of deposits acquired at the acquisition date.

+ References

No definition available.

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- Definition

Number of full-service retail bank offices acquired.

+ References

No definition available.

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- Definition

Amount of addition (reduction) to the amount at which an asset could be incurred (settled) in a current transaction between willing parties.

+ References

No definition available.

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- Definition

Number of shares of equity interests issued or issuable to acquire entity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)(4)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

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- 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.

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- Definition

Price of a single share of a number of saleable stocks paid or offered to be paid in a business combination.

+ References

No definition available.

+ Details

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Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

For receivables acquired in a business combination, excluding certain loans and debt securities acquired in a transfer (as defined), this element represents the gross contractual amounts receivable, by major class of receivable, such as loans, direct finance leases (as defined), and any other class of receivables.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
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- Definition

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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- Definition

Costs incurred to effect a business combination which have been expensed during the period. Such costs could include business integration costs, systems integration and conversion costs, and severance and other employee-related costs.

+ References

No definition available.

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- Definition

Amount of assets acquired at the acquisition date.

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-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)
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- Definition

Amount due from customers or clients for goods or services, including trade receivables, that have been delivered or sold in the normal course of business, and amounts due from others, including related parties expected to be converted to cash, sold or exchanged within one year or the normal operating cycle, if longer, acquired at the acquisition date.

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-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 20
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-Paragraph 1
-Subparagraph (c)
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- Definition

Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 20
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-Paragraph 1
-Subparagraph (a)
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-Paragraph 5
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- Definition

Amount of addition (reduction) to the amount at which a liability could be incurred (settled) in a current transaction between willing parties.

+ References

No definition available.

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- Definition

The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

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-Subparagraph (b)
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NEW WINDSOR ACQUISITION (Narrative) (Details)			3 Months Ended				12 Months Ended
NEW WINDSOR ACQUISITION (Narrative) (Details)	Jul. 01, 2017 USD ($) bank $ / shares shares	Jan. 05, 2005 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($) $ / shares	Mar. 31, 2017 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Business Acquisition [Line Items]
Number of community banking office locations, NWSB							7
Goodwill			$ 19,580,000				$ 19,580,000	$ 6,308,000
Total consideration paid		$ 8,663,000
Merger related expenses			53,000	$ 4,305,000	$ 208,000	$ 162,000	4,728,000	$ 472,000	$ 0
New Windsor
Business Acquisition [Line Items]
Number of community banking office locations, NWSB \| bank	7
Fair Value of total assets acquired	$ 319,821,000
Fair Value of total loans acquired	263,450,000
Fair Value of total deposits acquired	293,300,000
Goodwill	13,272,000		$ 13,300,000				$ 13,300,000
Cash portion of purchase price	$ 4,519,995
Percent of post transaction outstanding shares of the Corporation's common stock issued in merger	13.00%
Total consideration paid	$ 33,289,975
ACNB’s share price for purposes of calculation (in dollars per share) \| $ / shares	$ 30.50				$ 30.50
Loans receivable, gross amortized cost bases	$ 272,646,000
Interest rate fair value discount	731,000
Credit fair value discount	$ 4,501,000
Common Stock \| New Windsor
Business Acquisition [Line Items]
Shares of common stock issued in merger (in shares) \| shares	938,360
Investment Securities Available-for-sale \| New Windsor
Business Acquisition [Line Items]
Assets, fair value premium (discount)	$ 361,000
Time Deposits \| New Windsor
Business Acquisition [Line Items]
Assets, fair value premium (discount)	$ (847,500)
Core Deposit Intangible
Business Acquisition [Line Items]
Amortization period							10 years
Core Deposit Intangible \| New Windsor
Business Acquisition [Line Items]
Amortization period	10 years
Long-term Borrowings \| New Windsor
Business Acquisition [Line Items]
Liabilities, fair value discount	$ 312,500