| Component: (Network and Table) | |
|---|---|
| Network | 2414407 - Disclosure - EMPLOYEE BENEFIT PLANS - Principal Actuarial Assumptions(Details) (http://www.berkshirebank.com/role/EmployeeBenefitPlansPrincipalActuarialAssumptionsdetails) |
| 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 [Axis] | Pension Plans |
| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | Period [Axis] | |
|---|---|---|
2016-01-01 - 2016-12-31 | 2015-01-01 - 2015-12-31 | |
Projected benefit obligation, discount rate | ||
Net periodic pension cost, discount rate | 4.17% | 3.82% |
Net periodic pension cost, long term rate of return on plan assets | ||