Reportable Segments - Reportable Segments Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Mar. 31, 2018	Apr. 01, 2017	Sep. 30, 2017
Net sales	$ 698,651	$ 604,349	$ 1,375,945	$ 1,239,368
Operating income (loss)	17,315	32,571	48,872	66,474
Interest expense	(3,547)	(3,262)	(7,272)	(6,536)
Interest income	1,426	1,185	2,981	2,256
Miscellaneous	(477)	1,925	(823)	1,251
Income before income taxes	14,717	32,419	43,758	63,445
Total assets	1,909,974		1,909,974		$ 1,976,182
Elimination of inter-segment sales
Net sales	(27,501)	(22,448)	(59,205)	(51,498)
Corporate
Operating income (loss)	(42,947)	(24,921)	(71,324)	(51,820)
Corporate and eliminations
Total assets	135,401		135,401		44,390
AMER | Operating Segments
Net sales	301,835	272,064	600,878	586,715
Operating income (loss)	10,702	8,229	21,225	23,026
Total assets	599,331		599,331		595,851
APAC | Operating Segments
Net sales	350,375	309,758	696,498	619,727
Operating income (loss)	49,171	50,484	99,703	98,724
Total assets	984,816		984,816		1,163,111
EMEA | Operating Segments
Net sales	73,942	44,975	137,774	84,424
Operating income (loss)	389	$ (1,221)	(732)	$ (3,456)
Total assets	$ 190,426		$ 190,426		$ 172,830