| Component: (Network and Table) | |
|---|---|
| Network | 2408405 - Disclosure - Goodwill and Other Intangible Assets - Estimated Future Amortization Expense of Core Deposit Intangibles (Details) (http://amnb.com/role/GoodwillAndOtherIntangibleAssetsEstimatedFutureAmortizationExpenseOfCoreDepositIntangiblesDetails) |
| Table | (Implied) |
| Reporting Entity [Axis] | 0000741516 (http://www.sec.gov/CIK) |
| Goodwill and Intangible Assets Disclosure [Abstract] | Period [Axis] | |
|---|---|---|
2016-12-31 | 2015-12-31 | |
Goodwill and Intangible Assets Disclosure [Abstract] | ||
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract] | ||
2017 | ||
2018 | ||
2019 | ||
2020 | ||
2021 | ||
2022 and after | ||
Total | 1,719,000 | 2,683,000 |