CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Statement Of Financial Position [Abstract]
Allowance for doubtful accounts	$ 3,938	$ 3,297
Preferred stock, par value per share	$ 10	$ 10
Preferred stock, shares authorized	400,000	400,000
Preferred stock, shares issued	0	0
Common stock, par value per share	$ 10	$ 10
Common stock, shares authorized	40,000,000	33,922,433
Common stock, shares issued	34,248,218	33,922,433
Treasury stock, shares	3,361,040	3,061,040

Amount of allowance for credit loss on accounts receivable, classified as current.

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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Face amount or stated value per share of common stock.

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Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.

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Face amount or stated value per share of preferred stock nonredeemable or redeemable solely at the option of the issuer.

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Number of common and preferred shares that were previously issued and that were repurchased by the issuing entity and held in treasury on the financial statement date. This stock has no voting rights and receives no dividends.

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