CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
CURRENT ASSETS:
Accounts receivable, allowances for discounts and expected credit losses	$ 8,672	$ 8,045
Property, plant and equipment, accumulated depreciation	$ 265,904	$ 259,656
Stockholders' equity:
Common stock, par value (in dollars per share)	$ 2	$ 2
Common stock, shares authorized (in shares)	30,000,000	30,000,000
Common stock, shares issued (in shares)	23,936,036	23,936,036
Treasury stock - at cost (in shares)	2,223,698	2,018,982