Fair Value Measurements - Estimated Fair Values of Financial Instruments (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Financial Assets:
Cash and due from banks	$ 6,181	$ 6,789
Interest-bearing deposits	14,784	8,900
Federal funds sold	119	120
Securities available-for-sale	42,604us-gaap_AvailableForSaleSecurities	38,522us-gaap_AvailableForSaleSecurities
Restricted securities	2,430	1,638
Loans, net	295,242	247,912
Loans held for sale		196
Accrued interest receivable	1,197	1,124
Mortgage servicing rights	596us-gaap_ServicingAssetAtFairValueAmount	579us-gaap_ServicingAssetAtFairValueAmount
Financial Liabilities:
Non-interest-bearing liabilities	63,308	57,805
Savings and other interest-bearing deposits	122,502	114,056
Time deposits	121,775bayk_TimeDepositsFairValueDisclosure	96,486bayk_TimeDepositsFairValueDisclosure
Securities sold under repurchase agreements	6,012	9,118
FHLB advances	35,000	15,000
Accrued interest payable	149	167
Fair Value, Inputs, Level 1
Financial Assets:
Cash and due from banks	6,181	6,789
Interest-bearing deposits	14,784	8,900
Federal funds sold	119	120
Securities available-for-sale	845
Financial Liabilities:
Non-interest-bearing liabilities	63,308	57,805
Fair Value, Inputs, Level 2
Financial Assets:
Securities available-for-sale	41,759	37,610
Accrued interest receivable	1,197	1,124
Financial Liabilities:
Savings and other interest-bearing deposits	122,502	114,056
Securities sold under repurchase agreements	6,012	9,118
FHLB advances	35,951	15,923
Accrued interest payable	149	167
Fair Value, Inputs, Level 3
Financial Assets:
Securities available-for-sale		912
Restricted securities	2,430	1,638
Loans, net	300,481	253,139
Loans held for sale		196
Mortgage servicing rights	596	579
Financial Liabilities:
Time deposits	$ 122,662	$ 98,049

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Federal home loan bank advances long term fair value disclosure.

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Interest bearing deposits fair value disclosure.

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Fair value of accrued interest receivable primarily earned on loans.

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Non interest bearing deposits fair value disclosure.

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Savings and other interest bearing deposits fair value disclosure.

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Time deposits fair value disclosure.

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Fair value portion of accrued expenses.

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-Publisher SEC

-Name Regulation S-X (SX)

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-Paragraph 20

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Fair value portion of short term borrowing where a bank borrows, at the federal funds rate, from another bank and securities that an entity sells and agrees to repurchase at a specified date for a specified price.

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Fair value portion of loans held-for-sale including, but not limited to, mortgage loans and finance receivables.

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Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

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The aggregate value of all restricted investments.

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Fair value of an asset representing net future revenue from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements.

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