Condensed Consolidated Statements Of Equity Condensed Consolidatd Statements of Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Treasury Stock, Common	Additional Paid-in Capital	Retained Earnings	Foreign currency translation adjustments	Defined benefit pension adjustments
Balance (in shares) at Dec. 31, 2018		136,179	(202)
Balance at Dec. 31, 2018	$ 1,012,025	$ 1,362	$ (7,112)	$ 837,658	$ 213,753	$ (32,776)	$ (860)
Shares issued under stock plans (in shares)		572
Shares issued under stock plans	(6,812)	$ 5	0	(6,817)	0	0	0
Share-based compensation expense	4,653	$ 0	0	4,653	0	0	0
Repurchase and retirements of common stock (in shares)		(1,035)
Repurchase and retirements of common stock	(29,787)	$ (10)	0	(6,364)	(23,413)	0	0
Dividends declared	(9,510)	0	0		(9,517)	0	0
Dividends declared				7
Pension liability adjustments	24	0	0	0	0	0	24
Foreign currency translation adjustments	(2,787)	0	0	0	0	(2,787)	0
Net income	32,658	$ 0	$ 0	0	32,658	0	0
Balance (in shares) at Mar. 30, 2019		135,716	(202)
Balance at Mar. 30, 2019	1,000,464	$ 1,357	$ (7,112)	829,137	213,481	(35,563)	(836)
Balance (in shares) at Dec. 31, 2018		136,179	(202)
Balance at Dec. 31, 2018	1,012,025	$ 1,362	$ (7,112)	837,658	213,753	(32,776)	(860)
Pension liability adjustments	27
Foreign currency translation adjustments	(10,504)
Net income	197,422
Balance (in shares) at Sep. 28, 2019		135,141	(202)
Balance at Sep. 28, 2019	1,119,917	$ 1,351	$ (7,112)	837,212	332,579	(43,280)	(833)
Balance (in shares) at Mar. 30, 2019		135,716	(202)
Balance at Mar. 30, 2019	1,000,464	$ 1,357	$ (7,112)	829,137	213,481	(35,563)	(836)
Shares issued under stock plans (in shares)		49
Shares issued under stock plans	(572)	$ 0	0	(572)	0	0	0
Share-based compensation expense	4,936	$ 0	0	4,936	0	0	0
Repurchase and retirements of common stock (in shares)		(422)
Repurchase and retirements of common stock	(15,000)	$ (4)	0	(2,579)	(12,417)	0	0
Dividends declared	(9,550)	0	0	0	(9,550)	0	0
Pension liability adjustments	(14)	0	0	0	0	0	(14)
Foreign currency translation adjustments	(1,712)	0	0	0	0	(1,712)	0
Net income	123,997	$ 0	$ 0	0	123,997	0	0
Balance (in shares) at Jun. 29, 2019		135,343	(202)
Balance at Jun. 29, 2019	1,102,549	$ 1,353	$ (7,112)	830,922	315,511	(37,275)	(850)
Shares issued under stock plans (in shares)		156
Shares issued under stock plans	3,158	$ 2	0	3,156	0	0	0
Share-based compensation expense	5,326	$ 0	0	5,326	0	0	0
Repurchase and retirements of common stock (in shares)		(358)
Repurchase and retirements of common stock	(15,000)	$ (4)	0	(2,206)	(12,790)	0	0
Dividends declared	(10,895)	0	0	14	(10,909)	0	0
Pension liability adjustments	17	0	0	0	0	0	17
Foreign currency translation adjustments	(6,005)	0	0	0	0	(6,005)	0
Net income	40,767	$ 0	$ 0	0	40,767	0	0
Balance (in shares) at Sep. 28, 2019		135,141	(202)
Balance at Sep. 28, 2019	1,119,917	$ 1,351	$ (7,112)	837,212	332,579	(43,280)	(833)
Balance (in shares) at Dec. 31, 2019		134,930	(202)
Balance at Dec. 31, 2019	1,165,889	$ 1,349	$ (7,112)	842,784	366,127	(36,468)	(791)
Shares issued under stock plans (in shares)		483
Shares issued under stock plans	(10,889)	$ 5	0	(10,894)	0	0	0
Share-based compensation expense	4,994	$ 0	0	4,994	0	0	0
Repurchase and retirements of common stock (in shares)		(604)
Repurchase and retirements of common stock	(29,564)	$ (6)	0	(3,740)	(25,818)	0	0
Dividends declared	(10,758)	0	0		(10,773)	0	0
Dividends declared				15
Pension liability adjustments	10	0	0	0	0	0	10
Foreign currency translation adjustments	(9,361)	0	0	0	0	(9,361)	0
Net income	61,006	$ 0	$ 0	0	61,006	0	0
Balance (in shares) at Mar. 28, 2020		134,809	(202)
Balance at Mar. 28, 2020	1,171,327	$ 1,348	$ (7,112)	833,159	390,542	(45,829)	(781)
Balance (in shares) at Dec. 31, 2019		134,930	(202)
Balance at Dec. 31, 2019	1,165,889	$ 1,349	$ (7,112)	842,784	366,127	(36,468)	(791)
Pension liability adjustments	28
Foreign currency translation adjustments	(6,772)
Net income	208,345
Balance (in shares) at Sep. 26, 2020		135,238	(202)
Balance at Sep. 26, 2020	1,302,301	$ 1,352	$ (7,112)	835,953	516,111	(43,240)	(763)
Balance (in shares) at Mar. 28, 2020		134,809	(202)
Balance at Mar. 28, 2020	1,171,327	$ 1,348	$ (7,112)	833,159	390,542	(45,829)	(781)
Shares issued under stock plans (in shares)		139
Shares issued under stock plans	(82)	$ 1	0	(83)	0	0	0
Share-based compensation expense	5,655	0	0	5,655	0	0	0
Dividends declared	(10,980)	0	0	8	(10,988)	0	0
Pension liability adjustments	9	0	0	0	0	0	9
Foreign currency translation adjustments	(2,176)	0	0	0	0	(2,176)	0
Net income	68,036	$ 0	$ 0	0	68,036	0	0
Balance (in shares) at Jun. 27, 2020		134,948	(202)
Balance at Jun. 27, 2020	1,231,789	$ 1,349	$ (7,112)	838,739	447,590	(48,005)	(772)
Shares issued under stock plans (in shares)		290
Shares issued under stock plans	(8,686)	$ 3	0	(8,689)	0	0	0
Share-based compensation expense	5,903	0	0	5,903	0	0	0
Dividends declared	(10,782)	0	0	0	(10,782)	0	0
Pension liability adjustments	9	0	0	0	0	0	9
Foreign currency translation adjustments	4,765	0	0	0	0	4,765	0
Net income	79,303	$ 0	$ 0	0	79,303	0	0
Balance (in shares) at Sep. 26, 2020		135,238	(202)
Balance at Sep. 26, 2020	$ 1,302,301	$ 1,352	$ (7,112)	$ 835,953	$ 516,111	$ (43,240)	$ (763)