Deposits - Additional Information (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Cash And Short Term Investments [Line Items]
Aggregate amount of time deposits in denominations of $250000 or more	$ 16,500,000bayk_TimeDeposits250000OrMore	$ 7,000,000bayk_TimeDeposits250000OrMore
Overdraft demand deposits reclassified to loans	85,000	91,000
Brokered deposits	$ 8,000,000	$ 0

The aggregate of all domestic and foreign interest-bearing deposit liabilities.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.12)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 12

-Article 9

Name:	us-gaap_InterestBearingDepositLiabilities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant