Consolidated Statement of Shareholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss
Beginning Balance at Dec. 31, 2019	$ 1,355,710	$ 345	$ 639,372	$ 753,268	$ (37,275)
Beginning Balance (in shares) at Dec. 31, 2019		172,440
Increase (Decrease) in Stockholders' Equity
Net issuance of common stock under stock plans	48,235	$ 3	48,232
Issuance of common stock under stock plans (in shares)		1,822
Repurchase of common stock	(51,036)	$ (2)		(51,034)
Repurchase of common stock (in shares)		(1,215)
Stock-based compensation expense	$ 22,808		22,808
Cash dividends per common share (usd per share)	$ 0.110
Payment of dividends	$ (18,972)			(18,972)
Net income	19,335			19,335
Net unrealized gain (loss) on available-for-sale investments, net of tax	8,590				8,590
Reclassification of credit loss (recovery) on investments	75				75
Reclassification of net realized (gain) loss on the sale of available-for-sale investments	(2,805)				(2,805)
Foreign currency translation adjustment	(5,462)				(5,462)
Ending Balance (in shares) at Jun. 28, 2020		173,047
Ending Balance at Jun. 28, 2020	1,376,478	$ 346	710,412	702,597	(36,877)
Beginning Balance at Mar. 29, 2020	1,327,493	$ 344	664,132	713,208	(50,191)
Beginning Balance (in shares) at Mar. 29, 2020		171,688
Increase (Decrease) in Stockholders' Equity
Net issuance of common stock under stock plans	38,264	$ 2	38,262
Issuance of common stock under stock plans (in shares)		1,359
Stock-based compensation expense	$ 8,018		8,018
Cash dividends per common share (usd per share)	$ 0.055
Payment of dividends	$ (9,469)			(9,469)
Net income	(1,142)			(1,142)
Net unrealized gain (loss) on available-for-sale investments, net of tax	12,451				12,451
Reclassification of credit loss (recovery) on investments	(85)				(85)
Reclassification of net realized (gain) loss on the sale of available-for-sale investments	(955)				(955)
Foreign currency translation adjustment	1,903				1,903
Ending Balance (in shares) at Jun. 28, 2020		173,047
Ending Balance at Jun. 28, 2020	1,376,478	$ 346	710,412	702,597	(36,877)
Beginning Balance at Dec. 31, 2020	$ 1,262,202	$ 352	807,739	487,912	(33,801)
Beginning Balance (in shares) at Dec. 31, 2020	175,790	175,790
Increase (Decrease) in Stockholders' Equity
Net issuance of common stock under stock plans	$ 44,407	$ 2	44,405
Issuance of common stock under stock plans (in shares)		1,175
Repurchase of common stock	(20,877)	$ (1)		(20,876)
Repurchase of common stock (in shares)		(258)
Stock-based compensation expense	$ 22,739		22,739
Cash dividends per common share (usd per share)	$ 0.120
Payment of dividends	$ (21,192)			(21,192)
Net income	147,446			147,446
Net unrealized gain (loss) on available-for-sale investments, net of tax	(2,096)				(2,096)
Reclassification of net realized (gain) loss on the sale of available-for-sale investments	(68)				(68)
Foreign currency translation adjustment	$ (3,107)				(3,107)
Ending Balance (in shares) at Jul. 04, 2021	176,707	176,707
Ending Balance at Jul. 04, 2021	$ 1,429,454	$ 353	874,883	593,290	(39,072)
Beginning Balance at Apr. 04, 2021	1,357,001	$ 353	854,491	540,686	(38,529)
Beginning Balance (in shares) at Apr. 04, 2021		176,608
Increase (Decrease) in Stockholders' Equity
Net issuance of common stock under stock plans	9,663	$ 1	9,662
Issuance of common stock under stock plans (in shares)		277
Repurchase of common stock	(14,398)	$ (1)		(14,397)
Repurchase of common stock (in shares)		(178)
Stock-based compensation expense	$ 10,730		10,730
Cash dividends per common share (usd per share)	$ 0.060
Payment of dividends	$ (10,597)			(10,597)
Net income	77,598			77,598
Net unrealized gain (loss) on available-for-sale investments, net of tax	(138)				(138)
Reclassification of net realized (gain) loss on the sale of available-for-sale investments	(68)				(68)
Foreign currency translation adjustment	$ (337)				(337)
Ending Balance (in shares) at Jul. 04, 2021	176,707	176,707
Ending Balance at Jul. 04, 2021	$ 1,429,454	$ 353	$ 874,883	$ 593,290	$ (39,072)