Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Cash Flows From Operating Activities
Net income	$ 40,611	$ 27,539
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	22,060	20,023
Deferred compensation	2,694	(7,323)
Realized and unrealized (gains) losses on long-term investments	(534)	3,875
Stock-based compensation	2,539	1,202
Deferred income taxes	2,481	131
Other non-cash items	(40)	395
Changes in assets and liabilities:
Receivables, net	(63,243)	(30,767)
Inventories	(7,476)	(447)
Other current assets	(861)	(3,180)
Accounts payable and accrued liabilities	(9,377)	(16,583)
Pension liabilities	(451)	(236)
Environmental and legal liabilities	(21)	(947)
Deferred revenues	(80)	(157)
Net Cash Used In Operating Activities	(11,698)	(6,475)
Cash Flows From Investing Activities
Expenditures for property, plant and equipment	(37,632)	(33,202)
Asset acquisition (Note 17)	(3,503)	(2,040)
Business acquisition, net of cash acquired (Note 17)	(184,000)
Other, net	1,379	2,331
Net Cash Used In Investing Activities	(223,756)	(32,911)
Cash Flows From Financing Activities
Revolving debt and bank overdrafts, net	49,668
Dividends paid	(6,861)	(6,202)
Company stock repurchased	(989)	(7,243)
Stock option exercises	381	155
Other, net	(2,272)	(1,128)
Net Cash (Used In) Provided By Financing Activities	39,927	(14,418)
Effect of Exchange Rate Changes on Cash	(3,719)	(7,240)
Net Decrease in Cash and Cash Equivalents	(199,246)	(61,044)
Cash and Cash Equivalents at Beginning of Period	349,938	315,383
Cash and Cash Equivalents at End of Period	150,692	254,339
Supplemental Cash Flow Information
Cash payments of income taxes, net of refunds/payments	6,638	3,316
Cash payments of interest	$ 2,242	$ 2,122