Employee Benefit Plans - Stock Transactions - Stock Option Plans (Details) - USD ($)	3 Months Ended	12 Months Ended
Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Shares
Options Outstanding, beginning shares (in shares)	672,800
Options granted (in shares)	89,000	101,000
Options exercised (in shares)	(12,467)	(5,500)
Options Outstanding, ending shares (in shares)	749,333		672,800
Shares Exercisable	471,179
Weighted average exercise price
Weighted Average exercise Price: Options Outstanding, beginning (in usd per share)	$ 16.42
Weighted Average Exercise Price: Options granted (in usd per share)	19.21	$ 20.39
Weighted Average Exercise Price: Options exercised (in usd per share)	6.43
Weighted Average exercise Price: Options Outstanding, ending (in usd per share)	16.91		$ 16.42
Weighted average exercise price, Options Exercisable (in dollars per share)	$ 15.18
Weighted Average Remaining Contractual Life (in years): Options Outstanding	7 years 1 month 6 days		6 years 9 months 18 days
Weighted Average Remaining Contractual Life (in years): Options Exercisable	5 years 10 months 24 days
Aggregate Intrinsic Value: Options Outstanding	$ 3,858,402		$ 1,952,568
Aggregate Intrinsic Value: Options Exercisable	$ 3,228,220

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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Gross number of share options (or share units) granted during the period.

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Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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Number of options outstanding, including both vested and non-vested options.

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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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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Number of share options (or share units) exercised during the current period.

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