Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash Flows From Operating Activities
Net income	$ 96,724	$ 81,068
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	60,859	58,545
Deferred compensation	4,754	11,478
Realized and unrealized gains on long-term investments	(2,169)	(2,806)
Stock-based compensation	7,414	7,045
Deferred income taxes	257	(2,291)
Other non-cash items	860	2,192
Changes in assets and liabilities:
Receivables, net	(28,405)	(8,959)
Inventories	(2,574)	25,879
Other current assets	(4,215)	(3,750)
Accounts payable and accrued liabilities	12,041	(35,330)
Pension liabilities	(418)	(979)
Environmental and legal liabilities	(3,388)	800
Deferred revenues	(62)	(243)
Net Cash Provided By Operating Activities	141,678	132,649
Cash Flows From Investing Activities
Expenditures for property, plant and equipment	(84,903)	(70,829)
Asset acquistion (Note 17)	(2,040)
Business acquisition, net of cash acquired (Note 17)	(13,519)
Other, net	2,332	2,332
Net Cash Used In Investing Activities	(98,130)	(68,497)
Cash Flows From Financing Activities
Revolving debt and bank overdrafts, net		(6,929)
Other debt repayments	(14,286)	(37,143)
Dividends paid	(18,547)	(16,911)
Company stock repurchased	(13,753)	(13,184)
Stock option exercises	2,835	2,830
Other, net	(889)	(3,101)
Net Cash Used In Financing Activities	(44,640)	(74,438)
Effect of Exchange Rate Changes on Cash	(3,899)	(3,913)
Net Decrease in Cash and Cash Equivalents	(4,991)	(14,199)
Cash and Cash Equivalents at Beginning of Period	315,383	300,194
Cash and Cash Equivalents at End of Period	310,392	285,995
Supplemental Cash Flow Information
Cash payments of income taxes, net of refunds/payments	27,420	21,698
Cash payments of interest	$ 6,916	$ 9,311