Employee Benefit Plans, Restricted Stock Plan (Details) - Restricted Stock [Member] - USD ($)	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Deferred Compensation Arrangements [Abstract]
Number of shares authorized (in shares)	150,000		150,000
Number of shares available for grant (in shares)	124,564		124,564
Unvested Shares [Roll Forward]
Outstanding, beginning of period (in shares)	10,197		10,877
Granted (in shares)	4,647		4,647
Vested (in shares)	(4,058)		(4,738)
Outstanding, end of period (in shares)	10,786		10,786
Weighted Average Market Price [Roll Forward]
Outstanding, beginning of period (in dollars per share)	$ 60.12		$ 60.11
Granted (in dollars per share)	51.16		51.23
Vested (in dollars per share)	(59.23)		(59.32)
Outstanding, end of period (in dollars per share)	$ 56.60		$ 56.60
Additional General Disclosures [Abstract]
Share-based compensation expense	$ 83,000	$ 74,000	$ 165,000	$ 141,000
Compensation cost related to nonvested awards that has not yet been recognized	$ 610,000		$ 610,000
Period over which compensation cost is expected to be recognized			3 years

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Amount of cost to be recognized for nonvested award under share-based payment arrangement. Excludes share and unit options.

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Amount of noncash expense for share-based payment arrangement.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Per share or unit weighted-average fair value of nonvested award under share-based payment arrangement. Excludes share and unit options.

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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Number of shares authorized for issuance under share-based payment arrangement.

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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