CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash Flows from Operating Activities:
Net income	$ 205,604	$ 199,295	$ 191,624
Adjustments to reconcile net income to net cash provided by operations:
Depreciation	145,485	134,647	146,893
Amortization	9,317	4,246	5,325
Stock based compensation	19,824	20,612	19,749
Provision for (recovery of) doubtful accounts	561	(813)	741
Gain on sale of investment in unconsolidated affiliate	(2,013)
Deferred income taxes	(11,112)	(7,141)	(18,973)
Defined benefit plan expense	16,786	20,685	16,699
Equity in results of affiliates	191	718	1,917
Changes in balance sheet items, excluding effects from foreign currency adjustments:
Accounts receivables	(41,721)	(27,759)	(16,322)
Inventories	(834)	(18,925)	5,205
Prepaid and other current assets	(5,968)	(6,982)	(6,496)
Accounts payable and accrued liabilities	(12,474)	39,330	(24,319)
Income taxes payable	15,056	3,397	(10,949)
Retirement and deferred compensation plan liabilities	(7,486)	(29,576)	(370)
Other changes, net	(4,023)	(7,219)	5,605
Net Cash Provided by Operations	327,193	324,515	316,329
Cash Flows from Investing Activities:
Capital expenditures	(128,986)	(149,323)	(161,940)
Proceeds from sale of property and equipment	1,693	827	5,106
Insurance proceeds	986	3,739
Purchase of short-term investments		(32,769)
Maturity of short-term investments	29,485
Acquisition of business, net of cash acquired	(202,985)
Acquisition of intangible assets	(2,492)		(9)
Proceeds from sale of investment in unconsolidated affiliate	1,204
Notes receivable, net	593	1,296	(2,357)
Net Cash Used by Investing Activities	(300,502)	(176,230)	(159,200)
Cash Flows from Financing Activities:
Proceeds from Notes Payable	163,148		95,816
Repayments of notes payable		(227,362)
Proceeds from long-term obligations	5,963	225,236	253,520
Repayments of long-term obligations	(55,314)	(16,981)	(778)
Dividends paid	(76,659)	(71,247)	(71,072)
Credit facility costs		(1,216)	(720)
Proceeds from stock option exercises	53,453	64,003	36,015
Purchase of treasury stock			(340,517)
Common stock repurchased and retired	(131,371)	(13,887)
Excess tax benefit from exercise of stock options	9,171	8,388	6,998
Net Cash Used by Financing Activities	(31,609)	(33,066)	(20,738)
Effect of Exchange Rate Changes on Cash	(18,696)	(25,080)	(46,490)
Net (Decrease) Increase in Cash and Equivalents	(23,614)	90,139	89,901
Cash and Equivalents at Beginning of Period	489,901	399,762	309,861
Cash and Equivalents at End of Period	466,287	489,901	399,762
Supplemental Cash Flow Disclosure:
Interest paid	36,265	31,664	20,352
Income taxes paid	$ 82,201	$ 79,502	$ 94,578