CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash Flows from Operating Activities:
Net income	$ 214,090	$ 242,227	$ 194,766
Adjustments to reconcile net income to net cash provided by operations:
Depreciation	180,513	166,944	156,292
Amortization	39,787	27,608	15,455
Stock-based compensation	34,148	23,893	19,561
Provision for CECL in 2020 and allowance for doubtful accounts in 2019 and 2018	865	782	923
Loss (gain) on disposition of fixed assets	2,627	344	(770)
Net gain on remeasurement of equity securities	(64)	0	(6,500)
Deferred income taxes	(8,198)	8,746	(23,352)
Defined benefit plan expense	23,372	15,342	19,501
Equity in results of affiliates	1,443	(135)	229
Change in fair value of contingent consideration	5,230	0	0
Changes in balance sheet items, excluding effects from foreign currency adjustments:
Accounts and other receivables	13,455	8,811	(66,968)
Inventories	13,722	605	(25,183)
Prepaid and other current assets	(3,078)	6,596	(9,437)
Accounts payable, accrued and other liabilities	65,592	9,997	60,576
Income taxes payable	(6,091)	5,658	(3,155)
Retirement and deferred compensation plan liabilities	(7,267)	(3,956)	(22,762)
Other changes, net	7	995	4,452
Net Cash Provided by Operations	570,153	514,457	313,628
Cash Flows from Investing Activities:
Capital expenditures	(245,954)	(242,276)	(211,252)
Proceeds from sale of property, plant and equipment	5,261	4,301	4,466
Insurance proceeds	0	0	10,631
Purchase of short-term investments	(243)	0	0
Acquisition of business, net of cash acquired	(164,181)	(106,328)	(527,916)
Acquisition of intangible assets, net	(6,092)	(4,806)	(611)
Investment in equity securities	(39,628)	(3,530)	(10,000)
Proceeds from sale of investment in equity securities	0	16,487	0
Notes receivable, net	(1,141)	(116)	(779)
Net Cash Used by Investing Activities	(451,978)	(336,268)	(735,461)
Cash Flows from Financing Activities:
Proceeds from notes payable and overdrafts	22,342	50,854	49,069
Repayments of notes payable and overdrafts	(36,314)	(53,269)	(29,994)
Proceeds and repayments of short term revolving credit facility, net	27,000	(52,096)	81,063
Proceeds from long-term obligations	4,852	10,523	13,161
Repayments of long-term obligations	(64,735)	(67,276)	(72,290)
Payment of contingent consideration obligation	(2,765)	0	0
Dividends paid	(92,658)	(90,208)	(82,346)
Proceeds from stock option exercises	68,555	90,834	88,156
Purchase of treasury stock	0	(86,497)	(3,905)
Common stock repurchased and retired	0	0	(57,786)
Net Cash Used by Financing Activities	(73,723)	(197,135)	(14,872)
Effect of Exchange Rate Changes on Cash	13,545	(904)	(9,112)
Net Increase (Decrease) in Cash and Equivalents and Restricted Cash	57,997	(19,850)	(445,817)
Cash and Equivalents and Restricted Cash at Beginning of Period	246,973	266,823	712,640
Cash and Equivalents and Restricted Cash at End of Period	304,970	246,973	266,823
Supplemental Cash Flow Disclosure:
Interest paid	33,317	34,422	32,005
Income taxes paid	$ 93,575	$ 86,097	$ 96,048