Consolidated Condensed Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 59,486	$ 76,210	$ 77,695	$ 80,828
Other comprehensive income (loss), before tax
Foreign currency translation gain (loss)	651	(1,427)	1,665	(1,403)
Unrealized gain (loss) on marketable securities	(733)	385	8,755	2,500
Cumulative effect of adoption of ASU 2018-02	0	0	0	(257)
(Provision) benefit for income taxes	154	(81)	(1,838)	(525)
Comprehensive income	$ 59,558	$ 75,087	$ 86,277	$ 81,143
Accounting Standards Update [Extensible List]				us-gaap:AccountingStandardsUpdate201802Member