Fair Value of Financial Instruments - Estimated Fair Values and Related Carrying or Notional Amounts (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Financial Assets:
Securities - available-for-sale	$ 183,075	$ 196,398
Reported Value Measurement [Member]
Financial Assets:
Cash and Cash Equivalents	29,721	34,467
Interest-bearing time deposits	4,019	4,018
Securities - available-for-sale	183,075	196,398
Other Securities	3,717	3,717
Loans held for sale	1,679	1,221
Loans, net	831,943	816,156
Interest receivable	5,826	4,276
Financial Liabilities:
Total Deposits	928,859	919,340
Federal Funds Purchased and Securities Sold Under Agreement to Repurchase	27,026	39,495
Federal Home Loan Bank advances	5,000	5,000
Interest payable	367	318
Fair Value [Member]
Financial Assets:
Cash and Cash Equivalents	29,721	34,467
Interest-bearing time deposits	4,019	4,009
Securities - available-for-sale	183,075	196,398
Other Securities	3,717	3,717
Loans held for sale	1,679	1,221
Loans, net	815,856	819,193
Interest receivable	5,826	4,276
Financial Liabilities:
Total Deposits	928,986	920,109
Federal Funds Purchased and Securities Sold Under Agreement to Repurchase	27,026	39,495
Federal Home Loan Bank advances	5,001	5,021
Interest payable	367	318
Interest Bearing Deposits [Member] \| Reported Value Measurement [Member]
Financial Liabilities:
Total Deposits	545,179	532,660
Interest Bearing Deposits [Member] \| Fair Value [Member]
Financial Liabilities:
Total Deposits	545,208	532,660
Non Interest Bearing Deposits [Member] \| Reported Value Measurement [Member]
Financial Liabilities:
Total Deposits	197,088	199,114
Non Interest Bearing Deposits [Member] \| Fair Value [Member]
Financial Liabilities:
Total Deposits	197,088	199,114
Time Deposits [Member] \| Reported Value Measurement [Member]
Financial Liabilities:
Total Deposits	186,592	187,566
Time Deposits [Member] \| Fair Value [Member]
Financial Liabilities:
Total Deposits	186,690	188,335
Level 1 [Member]
Financial Assets:
Cash and Cash Equivalents	29,721	34,467
Securities - available-for-sale	20,771	20,978
Level 2 [Member]
Financial Assets:
Interest-bearing time deposits	4,019	4,009
Securities - available-for-sale	160,911	173,992
Financial Liabilities:
Total Deposits	197,088	199,114
Level 2 [Member] \| Non Interest Bearing Deposits [Member]
Financial Liabilities:
Total Deposits	197,088	199,114
Level 3 [Member]
Financial Assets:
Securities - available-for-sale	1,393	1,428
Other Securities	3,717	3,717
Loans held for sale	1,679	1,221
Loans, net	815,856	819,193
Interest receivable	5,826	4,276
Financial Liabilities:
Total Deposits	731,898	720,995
Federal Funds Purchased and Securities Sold Under Agreement to Repurchase	27,026	39,495
Federal Home Loan Bank advances	5,001	5,021
Interest payable	367	318
Level 3 [Member] \| Interest Bearing Deposits [Member]
Financial Liabilities:
Total Deposits	545,208	532,660
Level 3 [Member] \| Time Deposits [Member]
Financial Liabilities:
Total Deposits	$ 186,690	$ 188,335

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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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