Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash Flows From Operating Activities
Net income	$ 147,153,000	$ 137,895,000	$ 127,656,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	94,650,000	90,876,000	81,860,000
Deferred compensation	(9,393,000)	6,895,000	9,988,000
Realized and unrealized (gains) losses on long-term investments	8,188,000	(2,289,000)	(3,143,000)
Stock-based compensation	13,851,000	11,716,000	10,080,000
Deferred income taxes	(27,452,000)	(33,605,000)	(4,506,000)
Goodwill impairment (Note 4)	978,000
Other non-cash items	1,752,000	2,158,000	3,068,000
Changes in assets and liabilities, excluding effects of acquisitions:
Receivables, net	(26,153,000)	(104,231,000)	(23,417,000)
Inventories	(99,394,000)	(79,258,000)	(15,358,000)
Other current assets	(4,354,000)	(1,434,000)	(13,927,000)
Accounts payable and accrued liabilities	54,173,000	44,414,000	55,739,000
Pension liabilities	(1,821,000)	(1,729,000)	(612,000)
Environmental and legal liabilities	9,547,000	450,000	(3,021,000)
Deferred revenues	(962,000)	277,000	10,809,000
Net Cash Provided By Operating Activities	160,763,000	72,135,000	235,216,000
Cash Flows From Investing Activities
Expenditures for property, plant and equipment	(301,553,000)	(194,482,000)	(125,792,000)
Proceeds from asset disposition		4,149,000
Asset acquisition (Note 20)		(3,503,000)	(2,040,000)
Business acquisitions, net of cash acquired (Note 20)	(9,693,000)	(184,473,000)	(13,519,000)
Other, net	3,156,000	1,480,000	2,317,000
Net Cash Used In Investing Activities	(308,090,000)	(376,829,000)	(139,034,000)
Cash Flows From Financing Activities
Revolving debt and bank overdrafts, net (Note 6)	186,551,000	2,861,000
Other debt borrowings (Note 6)	75,000,000	200,000,000
Other debt repayments (Note 6)	(37,857,000)	(37,858,000)	(23,571,000)
Dividends paid	(30,573,000)	(28,083,000)	(25,405,000)
Company stock repurchased	(24,949,000)	(16,969,000)	(15,253,000)
Stock option exercises	782,000	1,369,000	2,926,000
Other, net	(2,745,000)	(3,987,000)	(3,631,000)
Net Cash Provided By (Used In) Financing Activities	166,209,000	117,333,000	(64,934,000)
Effect of Exchange Rate Changes on Cash	(4,318,000)	(3,391,000)	3,307,000
Net Increase (Decrease) in Cash and Cash Equivalents	14,564,000	(190,752,000)	34,555,000
Cash and Cash Equivalents at Beginning of Year	159,186,000	349,938,000	315,383,000
Cash and Cash Equivalents at End of Year	173,750,000	159,186,000	349,938,000
Supplemental Cash Flow Information
Cash payments of income taxes, net of refunds/payments	41,617,000	92,867,000	39,017,000
Cash payments of interest	$ 16,526,000	$ 9,542,000	$ 9,329,000