Securities - Available for Sale Securities (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 191,759	$ 190,863
Gross Unrealized Gains	8,929	5,820
Gross Unrealized Losses	(45)	(434)
Total securities available for sale, Fair Value	200,643	196,249
U.S. Treasury Securities and Obligations of U.S. Government Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	41,272	40,992
Gross Unrealized Gains	326	74
Gross Unrealized Losses	(20)	(129)
Total securities available for sale, Fair Value	41,578	40,937
Obligations of States and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	87,990	87,255
Gross Unrealized Gains	7,240	4,959
Gross Unrealized Losses	(12)	(62)
Total securities available for sale, Fair Value	95,218	92,152
Mortgage-backed Securities in Government Sponsored Entities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	62,016	62,135
Gross Unrealized Gains	1,244	681
Gross Unrealized Losses	(13)	(243)
Total securities available for sale, Fair Value	63,247	62,573
Total Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	191,278	190,382
Gross Unrealized Gains	8,810	5,714
Gross Unrealized Losses	(45)	(434)
Total securities available for sale, Fair Value	200,043	195,662
Equity Securities in Financial Institutions [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	481	481
Gross Unrealized Gains	119	106
Total securities available for sale, Fair Value	$ 600	$ 587

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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