Securities - Summary of Investments in an Unrealized Loss Position that were Temporarily Impaired (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, Less than 12 months - Fair Value	$ 52,580	$ 9,392
Securities available for sale, 12 months or more - Fair Value	14,462	35,368
Securities available for sale, Total - Fair Value	67,042	44,760
Securities available for sale, Less than 12 months - Unrealized (Loss)	(479)	(61)
Securities available for sale, 12 months or more - Unrealized (Loss)	(414)	(845)
Total Unrealized (Loss)	(893)	(906)
Securities held to maturity, Less than 12 months - Fair Value	35,843
Securities held to maturity, 12 months or more - Fair Value	0
Securities held to maturity, Total - Fair Value	35,843
Securities held to maturity, Less than 12 months - Unrealized (Loss)	(345)
Securities held to maturity, 12 months or more - Unrealized (Loss)	0
Total Unrealized (Loss)	(345)
Total securities, Less than 12 months - Fair Value	88,423
Total securities, 12 months or more - Fair Value	14,462
Total securities, Total - Fair Value	102,885
Total securities, Less than 12 months - Unrealized (Loss)	(824)
Total securities, 12 months or more - Unrealized (Loss)	(414)
Total Unrealized (Loss)	(1,238)
U.S. Agency and Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, Less than 12 months - Fair Value	50,185	8,677
Securities available for sale, 12 months or more - Fair Value	13,409	32,527
Securities available for sale, Total - Fair Value	63,594	41,204
Securities available for sale, Less than 12 months - Unrealized (Loss)	(464)	(60)
Securities available for sale, 12 months or more - Unrealized (Loss)	(379)	(747)
Total Unrealized (Loss)	(843)	(807)
Securities held to maturity, Less than 12 months - Fair Value	32,791
Securities held to maturity, 12 months or more - Fair Value	0
Securities held to maturity, Total - Fair Value	32,791
Securities held to maturity, Less than 12 months - Unrealized (Loss)	(326)
Securities held to maturity, 12 months or more - Unrealized (Loss)	0
Total Unrealized (Loss)	(326)
Obligations of States and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, Less than 12 months - Fair Value	2,395	715
Securities available for sale, 12 months or more - Fair Value	1,053	2,841
Securities available for sale, Total - Fair Value	3,448	3,556
Securities available for sale, Less than 12 months - Unrealized (Loss)	(15)	(1)
Securities available for sale, 12 months or more - Unrealized (Loss)	(35)	(98)
Total Unrealized (Loss)	(50)	$ (99)
Securities held to maturity, Less than 12 months - Fair Value	3,052
Securities held to maturity, 12 months or more - Fair Value	0
Securities held to maturity, Total - Fair Value	3,052
Securities held to maturity, Less than 12 months - Unrealized (Loss)	(19)
Securities held to maturity, 12 months or more - Unrealized (Loss)	0
Total Unrealized (Loss)	$ (19)

Available for sale securities and held to maturity securities continuous unrealized loss position accumulated loss.

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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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