Employee Deferred Compensation Plan and Employee Stock Purchase Plan	12 Months Ended
Dec. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Employee Deferred Compensation Plan and Employee Stock Purchase Plan	(5) Employee Deferred Compensation Plan and Employee Stock Purchase Plan The Company maintains a deferred compensation plan (“the Plan”) for all eligible employees. The Plan calls for each eligible employee, at the employee’s election, to participate in an income deferral arrangement under Internal Revenue Code Section 401(k). The plan allows eligible employees to make contributions, which cannot exceed 100% of compensation, or the annual dollar limit set by the Internal Revenue Code. The Company matches the first 5% of employee contributions. The Company’s contributions to the Plan amounted to $2,172, $1,997 and $1,914 in 2020, 2019 and 2018, respectively. During 2001, the Company’s Board of Directors adopted the AVD Employee Stock Purchase Plan (the “ESPP Plan”). The Plan allows eligible employees to purchase shares of common stock through payroll deductions at a discounted price. An original aggregate number of approximately 1,000,000 shares of the Company’s Common Stock, par value $0.10 per share (subject to adjustment for any stock dividend, stock split or other relevant changes in the Company’s capitalization) were allowed to be sold pursuant to the Plan, which is intended to qualify under Section 423 of the Internal Revenue Code. The Plan allows for purchases in a series of offering periods, each six months in duration, with new offering periods (other than the initial offering period) commencing on January 1 and July 1 of each year. The initial offering period commenced on July 1, 2001. Pursuant to action taken by the Company’s Board of Directors on December 10, 2010, the expiration of the Plan was extended to December 31, 2013. The Plan was amended and restated on June 30, 2011 following stockholders’ ratification of the extended expiration date. The Plan was amended as of June 6, 2018 following stockholders’ ratification of a ten-year extension to the expiration date (which now stands at December 31, 2028). Under the Plan, as amended as of June 6, 2018, 995,000 shares of the Company’s common stock were authorized. As of December 31, 2020, 2019, and 2018, 593,962, 643,630, and 690,859 shares, respectively, remained available under the plan. The expense recognized under the Plan was immaterial during the years ended December 31, 2020, 2019 and 2018, respectively. Shares of common stock purchased through the Plan in 2020, 2019 and 2018 were 49,668, 47,229 and 35,950, respectively.

Employee Deferred Compensation Plan and Employee Stock Purchase Plan

12 Months Ended

Dec. 31, 2020

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Employee Deferred Compensation Plan and Employee Stock Purchase Plan

(5) Employee Deferred Compensation Plan and Employee Stock Purchase Plan

The Company maintains a deferred compensation plan (“the Plan”) for all eligible employees. The Plan calls for each eligible employee, at the employee’s election, to participate in an income deferral arrangement under Internal Revenue Code Section 401(k). The plan allows eligible employees to make contributions, which cannot exceed 100% of compensation, or the annual dollar limit set by the Internal Revenue Code. The Company matches the first 5% of employee contributions. The Company’s contributions to the Plan amounted to $2,172, $1,997 and $1,914 in 2020, 2019 and 2018, respectively.

During 2001, the Company’s Board of Directors adopted the AVD Employee Stock Purchase Plan (the “ESPP Plan”). The Plan allows eligible employees to purchase shares of common stock through payroll deductions at a discounted price. An original aggregate number of approximately 1,000,000 shares of the Company’s Common Stock, par value $0.10 per share (subject to adjustment for any stock dividend, stock split or other relevant changes in the Company’s capitalization) were allowed to be sold pursuant to the Plan, which is intended to qualify under Section 423 of the Internal Revenue Code. The Plan allows for purchases in a series of offering periods, each six months in duration, with new offering periods (other than the initial offering period) commencing on January 1 and July 1 of each year. The initial offering period commenced on July 1, 2001. Pursuant to action taken by the Company’s Board of Directors on December 10, 2010, the expiration of the Plan was extended to December 31, 2013. The Plan was amended and restated on June 30, 2011 following stockholders’ ratification of the extended expiration date. The Plan was amended as of June 6, 2018 following stockholders’ ratification of a ten-year extension to the expiration date (which now stands at December 31, 2028). Under the Plan, as amended as of June 6, 2018, 995,000 shares of the Company’s common stock were authorized. As of December 31, 2020, 2019, and 2018, 593,962, 643,630, and 690,859 shares, respectively, remained available under the plan. The expense recognized under the Plan was immaterial during the years ended December 31, 2020, 2019 and 2018, respectively.

Shares of common stock purchased through the Plan in 2020, 2019 and 2018 were 49,668, 47,229 and 35,950, respectively.