Condensed Consolidated Statement of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Mar. 31, 2018	Apr. 01, 2017
Net income (loss)	$ 24,632	$ 31,717	$ (130,278)	$ 76,581
Other comprehensive income (loss), net of tax:
Change in foreign currency translation adjustments	908	1,612	554	(544)
Derivative financial instruments:
Change in net unrealized amount	2,860	794	1,453	(1,375)
Amount reclassified into net income	(2,867)	(460)	(1,342)	1,466
Defined benefit plans:
Changes in unrecognized net actuarial losses and unrecognized transition costs	(433)	170	(693)	1,230
Amortization of actuarial losses and transition costs	178	567	499	1,166
Total other comprehensive loss	646	2,683	471	1,943
Comprehensive income (loss)	$ 25,278	$ 34,400	$ (129,807)	$ 78,524