| Component: (Network and Table) | |
|---|---|
| Network | 41004 - Disclosure - Employee Benefit Plans (Weighted-Average Asset Allocations by Asset Category) (Detail) (http://www.bankevb.com/role/DisclosureEmployeeBenefitPlansWeightedAverageAssetAllocationsByAssetCategoryDetail) |
| Table | Schedule of Defined Benefit Plan Asset Allocation Targets [Table] |
| Reporting Entity [Axis] | 0001047170 (http://www.sec.gov/CIK) |
| Schedule of Defined Benefit Plan Asset Allocation Targets [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] | |||||
| Fixed income mutual funds | Equity mutual funds | Plan Asset Categories [Domain] | Fixed income mutual funds | Equity mutual funds | Plan Asset Categories [Domain] | |
Weighted-average asset allocations | 74.00% | 26.00% | 100.00% | 25.00% | 75.00% | 100.00% |