Accumulated Other Comprehensive Income (Loss) - Schedule of Changes in Accumulated Other Comprehensive Income (Loss) by Component Net of Tax (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Unrealized holding gain on available-for-sale securities arising during the period, Pretax	$ 808	$ 768
Reclassify gain included in income, Pretax		(35)
Unrealized holding gain on available-for-sale securities arising during the period, Tax Effect	290	279
Reclassify gain included in income, Tax Effect		12
Beginning balance, After-tax	(417)
Other comprehensive income	564	520
Ending Balance, After-tax	147
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, Pretax	(631)	(427)
Unrealized holding gain on available-for-sale securities arising during the period, Pretax	808	768
Reclassify gain included in income, Pretax		(35)
Amortization of held-to-maturity discount resulting from transfer , Pretax	46	54
Total other comprehensive income, Pretax	854	787
Ending balance, Pretax	223	360
Beginning balance, Tax Effect	214	145
Unrealized holding gain on available-for-sale securities arising during the period, Tax Effect	(275)	(261)
Reclassify gain included in income, Tax Effect		12
Amortization of held-to-maturity discount resulting from transfer, Tax Effect	(15)	(18)
Total other comprehensive income, Tax Effect	(290)	(267)
Ending Balance, Tax Effect	(76)	(122)
Beginning balance, After-tax	(417)	(282)
Unrealized holding gain on available-for-sale securities arising during the period, After-tax	533	507
Reclassify gain included in income, After-tax		(23)
Amortization of held-to-maturity discount resulting from transfer, After-tax	31	36
Other comprehensive income	564	520
Ending Balance, After-tax	$ 147	$ 238