Reclassifications Out of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2017	Jan. 01, 2017
Reclassifications out of accumulated other comprehensive loss
Balance at the beginning of the period	$ 928,453
Other comprehensive income (loss) before reclassifications	(3,383)	$ (14,844)
Amounts reclassified from accumulated other comprehensive income	(18)	(342)
Net current-period other comprehensive income (loss)	(3,401)	(15,186)
Balance at the end of the period	946,956
Foreign Currency Translation Adjustments
Reclassifications out of accumulated other comprehensive loss
Balance at the beginning of the period	(98,946)	(126,844)
Other comprehensive income (loss) before reclassifications	(3,467)	(16,182)
Amounts reclassified from accumulated other comprehensive income	0	0
Net current-period other comprehensive income (loss)	(3,467)	(16,182)
Balance at the end of the period	(102,413)	(143,026)
Gain (Loss) on Derivative Instruments
Reclassifications out of accumulated other comprehensive loss
Balance at the beginning of the period	446	(1,164)
Other comprehensive income (loss) before reclassifications	84	1,338
Amounts reclassified from accumulated other comprehensive income	(18)	(342)
Net current-period other comprehensive income (loss)	66	996
Balance at the end of the period	512	(168)
Accumulated Other Comprehensive Loss
Reclassifications out of accumulated other comprehensive loss
Balance at the beginning of the period	(98,500)	(128,008)
Balance at the end of the period	$ (101,901)	$ (143,194)