Financial Instruments (Narrative) (Details)			3 Months Ended
	Mar. 31, 2024 USD ($)	Aug. 16, 2023 USD ($)	Mar. 31, 2024 USD ($)	Mar. 18, 2024	Dec. 31, 2023 USD ($)	Aug. 31, 2023 USD ($)	Jun. 29, 2023 USD ($)	Dec. 31, 2021 USD ($)
Debt Instrument [Line Items]
Maximum leverage ratio allowed	3.50	3.75	3.50
Maximum leverage ratio allowed, after significant acquisition		4.25
Minimum interest coverage ratio required		3.00
Leverage ratio	1.17		1.17
Interest coverage ratio	14.38		14.38
Long-term debt	$ 439,134,000		$ 439,134,000		$ 456,885,000
Current maturities of long-term debt	4,445,000		4,445,000		4,218,000
Line of Credit
Debt Instrument [Line Items]
Long-term debt	429,000,000		429,000,000		446,000,000
Line of Credit | Interest rate swaps
Debt Instrument [Line Items]
Derivative, notional amount	$ 350,000,000		$ 350,000,000				$ 350,000,000	$ 350,000,000
Derivative, fixed interest rate				5.33%			0.8828%
All-in interest SOFR rate	2.51%		2.51%
Foreign bank debt
Debt Instrument [Line Items]
Long-term debt	$ 10,134,000		$ 10,134,000		10,885,000
Foreign bank debt | Heimbach
Debt Instrument [Line Items]
Long-term debt	10,100,000		10,100,000		10,900,000	$ 32,700,000
Current maturities of long-term debt	4,400,000		4,400,000		$ 4,200,000
Unsecured Debt | Line of Credit
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity		$ 800,000,000
Debt instrument, term		5 years
Borrowings outstanding	429,000,000		429,000,000
Line of credit facility, remaining borrowing capacity	$ 371,000,000		371,000,000
Debt covenant, maximum annual dividend payout amount			$ 40,000,000
Unsecured Debt | Line of Credit | SOFR
Debt Instrument [Line Items]
Total spread	1.625%