Share-Based Compensation - Additional Information (Detail) - USD ($)	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Compensation expense in stock compensation plans	$ 219,051	$ 247,301	$ 863,592	$ 1,100,000
Income tax benefit of stock compensation plans	46,001	51,933	181,354	233,851
Unrecognized compensation expense related to nonvested share-based compensation granted under the plan	1,000,000.0		$ 1,000,000.0
Weighted average period of unrecognized compensation expense			1 year 4 months 24 days
Cash from option exercises	8,100,000	772,969	$ 11,200,000	1,600,000
Tax benefit for tax deductions related to option exercises	$ 163,245	$ 22,414	$ 232,123	$ 38,376

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
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Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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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 tax benefit for recognition of expense of award under share-based payment arrangement.

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Amount of tax benefit from exercise of option under share-based payment arrangement.

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Amount of cash inflow from exercise of option under share-based payment arrangement.

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