Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2021	Mar. 28, 2020	Mar. 31, 2021	Mar. 28, 2020
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 109,262	$ 7,156	$ 132,777	$ 42,611
Other comprehensive income (loss), net of tax:
Hedge gain (loss) arising during the period, net of tax of $0 million and $0.2 million in the second quarter of 2021 and 2020, respectively, and $0 million and $0.9 million in the first six months of 2021 and 2020, respectively	7,017	701	238	(2,642)
Foreign currency translation adjustment, net of tax of $0 for each period	(15,851)	(10,559)	4,124	(412)
Unrealized loss on marketable securities, net of tax of $0 for each period	0	(537)	(307)	(544)
Amortization of net actuarial pension loss included in net income, net of tax of $0.3 million and $0.3 million in the second quarter of 2021 and 2020, respectively, and $0.6 million and $0.6 million in the first six months of 2021 and 2020, respectively	744	680	1,476	1,354
Change in unamortized pension loss during the period related to changes in foreign currency	1,018	81	(94)	(541)
Other comprehensive income (loss)	(7,072)	(9,634)	5,437	(2,785)
Comprehensive income (loss)	$ 102,190	$ (2,478)	$ 138,214	$ 39,826