Financial Instruments with Off Balance Sheet Risk - Schedule of Bank's Exposure to Credit Loss (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Contract or Notional Amount	$ 58,002	$ 49,397
Commitments to Grant Loans [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Contract or Notional Amount	22,310	19,602
Unfunded Commitments of Existing Loans [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Contract or Notional Amount	32,279	26,479
Standby and Performance Letters of Credit [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Contract or Notional Amount	$ 3,413	$ 3,316