CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN TOTAL EQUITY (unaudited) - USD ($) $ in Thousands	Total		Common Shares	Capital in Excess of Stated Value	Accumulated Other Comprehensive Loss	Retained Earnings	Noncontrolling Interests	Impact of new accounting pronouncements	Impact of new accounting pronouncements Retained Earnings
Beginning Balance at Dec. 31, 2018	$ 1,772,278		$ 7,175	$ 304,709	$ (740,913)	$ 2,188,115	$ 13,192	$ (6,771)	$ (6,771)
Beginning balance (shares) at Dec. 31, 2018			99,829,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income/(loss)	73,768					73,663	105
Other comprehensive income/(loss):
Translation gain/(loss)	(2,972)				(2,852)		(120)
Defined benefit plan adjustment, net of tax	7,156				7,156
Derivative financial instruments, net of tax	1,864				1,864
Other comprehensive income/(loss)	6,048				6,168		(120)
Dividends	(41,534)					(41,534)
Dividends paid to noncontrolling interests	(214)						(214)
Issuance of stock awards	399			399
Issuance of stock awards (shares)			340,000
Shares repurchased	(7,395)			(7,395)
Shares repurchased (shares)			(133,000)
Stock-based compensation	4,560			4,560
Ending Balance at Mar. 31, 2019	1,801,139		$ 7,175	302,273	(734,745)	2,213,473	12,963
Ending balance (shares) at Mar. 31, 2019			100,036,000
Beginning Balance at Dec. 31, 2018	1,772,278		$ 7,175	304,709	(740,913)	2,188,115	13,192	(6,771)	(6,771)
Beginning balance (shares) at Dec. 31, 2018			99,829,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income/(loss)	247,337
Other comprehensive income/(loss):
Translation gain/(loss)	(27,655)
Defined benefit plan adjustment, net of tax	(7,887)
Derivative financial instruments, net of tax	1,290
Other comprehensive income/(loss)					(33,460)
Ending Balance at Sep. 29, 2019	1,854,313		$ 7,175	308,868	(774,373)	2,300,006	12,637
Ending balance (shares) at Sep. 29, 2019			100,082,000
Beginning Balance at Dec. 31, 2018	$ 1,772,278		$ 7,175	304,709	(740,913)	2,188,115	13,192	(6,771)	(6,771)
Beginning balance (shares) at Dec. 31, 2018			99,829,000
Other comprehensive income/(loss):
Shares repurchased (shares)	0
Ending Balance at Dec. 31, 2019	$ 1,815,705	[1]	$ 7,175	310,778	(816,803)	2,301,532	13,023	(209)	(209)
Ending balance (shares) at Dec. 31, 2019	100,198,000		100,198,000
Beginning Balance at Mar. 31, 2019	$ 1,801,139		$ 7,175	302,273	(734,745)	2,213,473	12,963
Beginning balance (shares) at Mar. 31, 2019			100,036,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income/(loss)	81,286					81,159	127
Other comprehensive income/(loss):
Translation gain/(loss)	9,745				9,573		172
Defined benefit plan adjustment, net of tax	1,807				1,807
Derivative financial instruments, net of tax	(481)				(481)
Other comprehensive income/(loss)	11,071				10,899		172
Dividends	(43,353)					(43,353)
Issuance of stock awards	326			326
Issuance of stock awards (shares)			58,000
Shares repurchased	(1,155)			(1,155)
Shares repurchased (shares)			(19,000)
Stock-based compensation	4,306			4,306
Ending Balance at Jun. 30, 2019	1,853,620		$ 7,175	305,750	(723,846)	2,251,279	13,262
Ending balance (shares) at Jun. 30, 2019			100,075,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income/(loss)	92,283					92,064	219
Other comprehensive income/(loss):
Translation gain/(loss)	(34,428)				(33,584)		(844)
Defined benefit plan adjustment, net of tax	(16,850)				(16,850)
Derivative financial instruments, net of tax	(93)				(93)
Other comprehensive income/(loss)	(51,371)				(50,527)		(844)
Dividends	(43,337)					(43,337)
Issuance of stock awards	330			330
Issuance of stock awards (shares)			9,000
Shares repurchased	(147)			(147)
Shares repurchased (shares)			(2,000)
Stock-based compensation	2,935			2,935
Ending Balance at Sep. 29, 2019	1,854,313		$ 7,175	308,868	(774,373)	2,300,006	12,637
Ending balance (shares) at Sep. 29, 2019			100,082,000
Beginning Balance at Dec. 31, 2019	$ 1,815,705	[1]	$ 7,175	310,778	(816,803)	2,301,532	13,023	(209)	(209)
Beginning balance (shares) at Dec. 31, 2019	100,198,000		100,198,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income/(loss)	$ 80,236					80,445	(209)
Other comprehensive income/(loss):
Translation gain/(loss)	(95,212)				(93,575)		(1,637)
Defined benefit plan adjustment, net of tax	5,780				5,780
Derivative financial instruments, net of tax	(4,555)				(4,555)
Other comprehensive income/(loss)	(93,987)				(92,350)		(1,637)
Dividends	(43,339)					(43,339)
Issuance of stock awards	376			376
Issuance of stock awards (shares)			196,000
Shares repurchased	(3,938)			(3,938)
Shares repurchased (shares)			(65,000)
Stock-based compensation	597			597
Ending Balance at Mar. 29, 2020	1,755,441		$ 7,175	307,813	(909,153)	2,338,429	11,177
Ending balance (shares) at Mar. 29, 2020			100,329,000
Beginning Balance at Dec. 31, 2019	$ 1,815,705	[1]	$ 7,175	310,778	(816,803)	2,301,532	13,023	$ (209)	$ (209)
Beginning balance (shares) at Dec. 31, 2019	100,198,000		100,198,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income/(loss)	$ 218,524
Other comprehensive income/(loss):
Translation gain/(loss)	(37,701)
Defined benefit plan adjustment, net of tax	15,476
Derivative financial instruments, net of tax	$ (440)
Other comprehensive income/(loss)					(20,411)
Shares repurchased (shares)	0
Ending Balance at Sep. 27, 2020	$ 1,881,333		$ 7,175	310,912	(837,214)	2,390,272	10,188
Ending balance (shares) at Sep. 27, 2020	100,416,000		100,416,000
Beginning Balance at Mar. 29, 2020	$ 1,755,441		$ 7,175	307,813	(909,153)	2,338,429	11,177
Beginning balance (shares) at Mar. 29, 2020			100,329,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income/(loss)	54,990					55,211	(221)
Other comprehensive income/(loss):
Translation gain/(loss)	32,864				33,454		(590)
Defined benefit plan adjustment, net of tax	4,416				4,416
Derivative financial instruments, net of tax	1,830				1,830
Other comprehensive income/(loss)	39,110				39,700		(590)
Dividends	(43,451)					(43,451)
Issuance of stock awards	287			287
Issuance of stock awards (shares)			2,000
Shares repurchased	(12)			(12)
Shares repurchased (shares)			(1,000)
Stock-based compensation	1,339			1,339
Ending Balance at Jun. 28, 2020	1,807,704		$ 7,175	309,427	(869,453)	2,350,189	10,366
Ending balance (shares) at Jun. 28, 2020			100,330,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income/(loss)	83,298					83,449	(151)
Other comprehensive income/(loss):
Translation gain/(loss)	24,647				24,674		(27)
Defined benefit plan adjustment, net of tax	5,280				5,280
Derivative financial instruments, net of tax	2,285				2,285
Other comprehensive income/(loss)	32,212				32,239		(27)
Dividends	(43,366)					(43,366)
Issuance of stock awards	256			256
Issuance of stock awards (shares)			150,000
Shares repurchased	(3,385)			(3,385)
Shares repurchased (shares)			(64,000)
Stock-based compensation	4,614			4,614
Ending Balance at Sep. 27, 2020	$ 1,881,333		$ 7,175	$ 310,912	$ (837,214)	$ 2,390,272	$ 10,188
Ending balance (shares) at Sep. 27, 2020	100,416,000		100,416,000

[1] The year-end condensed consolidated balance sheet data was derived from audited financial statements, but does not include all disclosures required by accounting principles generally accepted in the United States of America.