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	9,971	$ 1	9,970
Issuance of common stock under stock plans (in shares)		463
Repurchase of common stock	(51,036)	$ (2)		(51,034)
Repurchase of common stock (in shares)		(1,215)
Stock-based compensation expense	14,790		14,790
Payment of dividends	(9,503)			(9,503)
Net income	20,477			20,477
Net unrealized gain (loss) on available-for-sale investments, net of tax	(3,861)				(3,861)
Reclassification of credit loss (recovery) on investments	160				160
Reclassification of net realized (gain) loss on the sale of available-for-sale investments	(1,850)				(1,850)
Foreign currency translation adjustment	(7,365)				(7,365)
Ending Balance (in shares) at Mar. 29, 2020		171,688
Ending Balance at Mar. 29, 2020	1,327,493	$ 344	664,132	713,208	(50,191)
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	$ 34,744	$ 1	34,743
Issuance of common stock under stock plans (in shares)		898
Repurchase of common stock	(6,479)			(6,479)
Repurchase of common stock (in shares)		(80)
Stock-based compensation expense	12,009		12,009
Payment of dividends	(10,595)			(10,595)
Net income	69,848			69,848
Net unrealized gain (loss) on available-for-sale investments, net of tax	(1,958)				(1,958)
Reclassification of net realized (gain) loss on the sale of available-for-sale investments					0
Foreign currency translation adjustment	$ (2,770)				(2,770)
Ending Balance (in shares) at Apr. 04, 2021	176,608	176,608
Ending Balance at Apr. 04, 2021	$ 1,357,001	$ 353	$ 854,491	$ 540,686	$ (38,529)