Securities - Available for Sale Securities (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 343,323
Fair Value	346,294	$ 230,230
U.S. Treasury Securities and Obligations of U.S. Government Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	30,623	30,450
Gross Unrealized Gains	202	100
Gross Unrealized Losses	(140)	(192)
Fair Value	30,685	30,358
Obligations of States and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	168,993	114,002
Gross Unrealized Gains	3,680	4,226
Gross Unrealized Losses	(602)	(172)
Fair Value	172,071	118,056
Mortgage-back Securities in Government Sponsored Entities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	143,707	82,098
Gross Unrealized Gains	1,024	408
Gross Unrealized Losses	(1,193)	(690)
Fair Value	143,538	81,816
Total Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	343,323	226,550
Gross Unrealized Gains	4,906	4,734
Gross Unrealized Losses	(1,935)	(1,054)
Fair Value	$ 346,294	$ 230,230

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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-Publisher FASB
-Name Accounting Standards Codification
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