Condensed Financial Statements of Parent Company - Balance Sheets (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Related party receivables:
Total Assets	$ 1,116,163	$ 1,107,009
Liabilities
Dividends payable	1,379	1,193
Total liabilities	972,876	972,872
Stockholders' Equity	143,287	134,137	$ 125,577	$ 120,097
Total Liabilities and Stockholders' Equity	1,116,163	1,107,009
Farmers & Merchants State Bank [Member]
Assets
Cash	1,727	277
Related party receivables:
Dividends and accounts receivable from subsidiary	9,808	2,038
Accrued interest receivable - municipals	67	110
Securities - municipals	12,977	18,944
Certificate of deposits	1,974	1,974
Investment in subsidiaries	118,151	112,025
Total Assets	144,704	135,368
Liabilities
Accrued expenses	38	38
Dividends payable	1,379	1,193
Total liabilities	1,417	1,231
Stockholders' Equity	143,287	134,137
Total Liabilities and Stockholders' Equity	$ 144,704	$ 135,368

Accrued interest receivable and other assets.

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Dividend and accounts receivable from subsidiary.

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Carrying value as of the balance sheet date of obligations incurred and payable, pertaining to costs that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered. Examples include taxes, interest, rent and utilities.

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Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Excludes cash and cash equivalents within disposal group and discontinued operation.

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Carrying value as of the balance sheet date of dividends declared but unpaid on equity securities issued by the entity and outstanding.

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This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

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Sum of the carrying amounts as of the balance sheet date of all liabilities that are recognized. Liabilities are probable future sacrifices of economic benefits arising from present obligations of an entity to transfer assets or provide services to other entities in the future.

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Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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