Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash Flows From Operating Activities
Net income	$ 85,807	$ 81,661
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	60,778	57,121
Deferred compensation	4,971	5,263
Realized and unrealized gains on long-term investments	(1,241)	(3,677)
Stock-based compensation	6,722	6,248
Deferred income taxes	6,410	7,132
Other non-cash items	1,370	3,738
Changes in assets and liabilities:
Receivables, net	(34,807)	(37,713)
Inventories	(21,586)	14,789
Other current assets	727	(631)
Accounts payable and accrued liabilities	(6,906)	(5,872)
Pension liabilities	(5,059)	(2,141)
Environmental and legal liabilities	(763)	(392)
Deferred revenues	(243)	(843)
Net Cash Provided By Operating Activities	96,180	124,683
Cash Flows From Investing Activities
Expenditures for property, plant and equipment	(62,895)	(57,902)
Business acquisition (Note 16)	(21,475)	(4,339)
Other, net	1,684	(759)
Net Cash Used In Investing Activities	(82,686)	(63,000)
Cash Flows From Financing Activities
Revolving debt and bank overdrafts, net	1,379	(7,309)
Other debt repayments	(5,714)	(5,714)
Dividends paid	(15,225)	(13,841)
Company stock repurchased	(13,500)	(4,500)
Stock option exercises	3,488	3,127
Other, net	(4,504)	(1,649)
Net Cash Used In Financing Activities	(34,076)	(29,886)
Effect of Exchange Rate Changes on Cash	(4,324)	6,560
Net Decrease in Cash and Cash Equivalents	(24,906)	38,357
Cash and Cash Equivalents at Beginning of Period	298,894	225,743
Cash and Cash Equivalents at End of Period	273,988	264,100
Supplemental Cash Flow Information
Cash payments of income taxes, net of refunds/payments	25,190	22,377
Cash payments of interest	$ 8,553	$ 9,113