Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash Flows From Operating Activities
Net Income	$ 76,037	$ 57,081	$ 72,337
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	66,985	63,804	56,400
Deferred compensation	6,500	(11,903)	9,496
Realized and unrealized gain on long-term investments	(21)	(241)	(2,611)
Stock-based compensation	4,374	(68)	2,783
Deferred income taxes	3,001	5,306	259
Other non-cash items	3,830	8,260	7,253
Changes in assets and liabilities, excluding effects of acquisitions:
Receivables, net	4,160	(21,229)	(12,749)
Inventories	2,851	(18,521)	(3,794)
Other current assets	(3,410)	1,430	(5,950)
Accounts payable and accrued liabilities	21,219	(4,376)	26,256
Pension liabilities	932	(2,709)	1,997
Environmental and legal liabilities	(1,398)	6,493	(353)
Deferred revenues	(1,345)	(732)	2,428
Excess tax benefit from stock options and awards	(442)	(640)	(3,438)
Net Cash Provided By Operating Activities	183,273	81,955	150,314
Cash Flows From Investing Activities
Expenditures for property, plant and equipment	(119,349)	(101,819)	(92,865)
Business acquisitions, net of cash acquired (Note 20)	(5,133)		(68,212)
Proceeds from sale of product line (Note 21)	3,262
Sale of mutual funds	901	908	698
Other, net	(5,651)	(8,310)	(7,179)
Net Cash Used In Investing Activities	(125,970)	(109,221)	(167,558)
Cash Flows From Financing Activities
Revolving debt and bank overdrafts, net	(26,217)	14,219	4,820
Other debt borrowings	100,000	4,923	100,000
Other debt repayments	(13,098)	(12,656)	(17,618)
Dividends paid	(16,300)	(15,387)	(14,474)
Company stock repurchased	(2,000)	(7,924)	(2,275)
Stock option exercises	777	1,754	3,977
Excess tax benefit from stock options and awards	442	640	3,438
Other, net	(673)	(421)	(1,615)
Net Cash Provided By (Used In) Financing Activities	42,931	(14,852)	76,253
Effect of Exchange Rate Changes on Cash	(9,306)	(6,014)	(2,537)
Net Increase (Decrease) in Cash and Cash Equivalents	90,928	(48,132)	56,472
Cash and Cash Equivalents at Beginning of Year	85,215	133,347	76,875
Cash and Cash Equivalents at End of Year	176,143	85,215	133,347
Supplemental Cash Flow Information
Cash payments of income taxes, net of refunds	21,784	23,142	22,691
Cash payments of interest	$ 11,943	$ 12,447	$ 11,281