Consolidated Statements Of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 28, 2020	Mar. 30, 2019	Mar. 28, 2020	Mar. 30, 2019
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 7,156	$ (43,513)	$ 42,611	$ (22,528)
Other comprehensive income (loss), net of tax:
Hedge gain (loss) arising during the period, net of tax of $0.2 million in the second quarter of 2020 and 2019, respectively, and $0.9 million and $0.2 million in the first six months of 2020 and 2019, respectively	701	2,955	(2,642)	826
Net hedge (gain) loss reclassified into earnings, net of tax of $0.0 million in the second quarter of 2020 and 2019, respectively, and $0.0 million and $0.1 million in the first six months of 2020 and 2019, respectively	0	0	0	(549)
Realized and unrealized gain (loss) on hedging instruments	701	2,955	(2,642)	277
Foreign currency translation adjustment, net of tax of $0 for each period	(10,559)	(4,033)	(412)	(11,602)
Unrealized gain (loss) on marketable securities, net of tax of $0 for each period	(537)	289	(544)	302
Amortization of net actuarial pension loss included in net income, net of tax of $0.3 million and $0.2 million in the second quarter of 2020 and 2019, respectively, and $0.6 million and $0.3 million in the first six months of 2020 and 2019, respectively	680	428	1,354	858
Change in unamortized pension loss during the period related to changes in foreign currency	81	345	(541)	626
Other comprehensive loss	(9,634)	(16)	(2,785)	(9,539)
Comprehensive income (loss)	$ (2,478)	$ (43,529)	$ 39,826	$ (32,067)