| Component: (Network and Table) | |
|---|---|
| Network | 2413407 - Disclosure - RETIREMENT PLANS (Pension Plan Weighted-Average Assets' Allocations) (Details) (http://www.acnb.com/role/RetirementPlansPensionPlanWeightedAverageAssetsAllocationsDetails) |
| Table | Schedule of Defined Benefit Plans Disclosures [Table] |
| Reporting Entity [Axis] | 0000715579 (http://www.sec.gov/CIK) |
| Defined Benefit Plan Disclosure [Line Items] | Period [Axis] | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
2016-01-01 - 2016-12-31 | 2015-01-01 - 2015-12-31 | |||||||||
| Defined Benefit Plan, Asset Categories [Axis] | Defined Benefit Plan, Asset Categories [Axis] | |||||||||
| Equity securities | Debt securities | Short-term fixed income | Real estate | Plan Asset Categories [Domain] | Equity securities | Debt securities | Short-term fixed income | Real estate | Plan Asset Categories [Domain] | |
Weighted-Average Asset Allocation | ||||||||||