Fair Value Measurements (Quantitative Information About Significant Unobservable Inputs Used In The Fair Value Measurement Of MSRs) (Details)	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Fair Value Measurements [Abstract]
Servicing fees	0.25%evbn_FairValueInputsServicingFees	0.25%evbn_FairValueInputsServicingFees
Discount rate	9.52%us-gaap_FairValueInputsDiscountRate	9.52%us-gaap_FairValueInputsDiscountRate
Prepayment rate (CPR)	9.80%us-gaap_FairValueInputsPrepaymentRate	9.28%us-gaap_FairValueInputsPrepaymentRate

Interest rate used to find the present value of an amount to be paid or received in the future as an input to measure fair value. For example, but not limited to, weighted average cost of capital (WACC), cost of capital, cost of equity and cost of debt.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (bbb)

-URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258

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