Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Cash Flows From Operating Activities
Net income	$ 50,370,000	$ 40,204,000	$ 147,153,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	112,197,000	105,338,000	94,650,000
Deferred compensation	2,155,000	4,371,000	(9,393,000)
Realized and unrealized (gains) losses on long-term investments	(3,323,000)	(4,314,000)	8,188,000
Stock-based compensation	5,347,000	5,741,000	13,851,000
Deferred income taxes	(10,291,000)	18,303,000	(27,452,000)
Goodwill and other intangibles impairment (Note 4)		2,038,000	978,000
Other non-cash items	2,812,000	5,123,000	1,752,000
Changes in assets and liabilities, excluding effects of acquisitions:
Receivables, net	9,036,000	32,007,000	(26,153,000)
Inventories	(37,178,000)	144,846,000	(99,394,000)
Other current assets	(1,000)	(4,528,000)	(4,354,000)
Accounts payable and accrued liabilities	33,970,000	(158,924,000)	54,173,000
Pension liabilities	(131,000)	(1,204,000)	(1,821,000)
Environmental and legal liabilities	(695,000)	(11,985,000)	9,547,000
Deferred revenues	(2,215,000)	(2,140,000)	(962,000)
Net Cash Provided By Operating Activities	162,053,000	174,876,000	160,763,000
Cash Flows From Investing Activities
Expenditures for property, plant and equipment	(122,776,000)	(260,335,000)	(301,553,000)
Business acquisitions, net of cash acquired (Note 20)			(9,693,000)
Other, net	5,831,000	1,669,000	3,156,000
Net Cash Used In Investing Activities	(116,945,000)	(258,666,000)	(308,090,000)
Cash Flows From Financing Activities
Revolving debt and bank overdrafts, net (Note 6)	19,886,000	104,717,000	186,551,000
Other debt borrowings (Note 6)			75,000,000
Other debt repayments (Note 6)	(48,571,000)	(37,858,000)	(37,857,000)
Dividends paid	(33,950,000)	(32,868,000)	(30,573,000)
Company stock repurchased			(24,949,000)
Stock option exercises	1,112,000	2,795,000	782,000
Other, net	(2,997,000)	(3,502,000)	(2,745,000)
Net Cash Provided By (Used In) Financing Activities	(64,520,000)	33,284,000	166,209,000
Effect of Exchange Rate Changes on Cash	(10,746,000)	6,579,000	(4,318,000)
Net Increase (Decrease) in Cash and Cash Equivalents	(30,158,000)	(43,927,000)	14,564,000
Cash and Cash Equivalents at Beginning of Year	129,823,000	173,750,000	159,186,000
Cash and Cash Equivalents at End of Year	99,665,000	129,823,000	173,750,000
Supplemental Cash Flow Information
Cash payments of income taxes, net of refunds/payments	(12,342,000)	29,558,000	41,617,000
Cash payments of interest	$ 29,848,000	$ 27,951,000	$ 16,526,000