| Component: (Network and Table) | |
|---|---|
| Network | 2414409 - Disclosure - EMPLOYEE BENEFIT PLANS - Estimated Benefit Payments (Details) (http://www.berkshirebank.com/role/EmployeeBenefitPlansEstimatedBenefitPaymentsDetails) |
| Table | Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Table] |
| Reporting Entity [Axis] | 0001108134 (http://www.sec.gov/CIK) |
| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | Period [Axis] | |
|---|---|---|
2016-12-31 | ||
| Defined Benefit Plans and Other Postretirement Benefit Plans [Axis] | ||
| Pension Plans | Postretirement Benefits | |
2017 | ||
2018 | ||
2019 | ||
2020 | ||
2021 | ||
2022-2026 | ||