Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 30, 2017	Sep. 30, 2017	Jul. 01, 2017	Apr. 01, 2017	Dec. 31, 2016	Sep. 29, 2018	Sep. 30, 2017	Oct. 01, 2016
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 461,548	$ 482,342	$ 481,118	$ 477,565	$ 490,298	$ 464,107	$ 422,833	$ 346,073	$ 1,902,573	$ 1,723,311	$ 857,385
Gross profit	189,902	208,336	215,430	217,023	222,054	207,186	179,515	141,514	830,691	750,269	381,392
Net income	$ 73,185	$ 66,970	$ 65,302	$ 41,901	$ 73,752	$ 61,117	$ 41,845	$ 30,408	$ 247,358	$ 207,122	$ 87,502
Net income per basic share (in dollars per share)	$ 3.02	$ 2.72	$ 2.64	$ 1.70	$ 3.00	$ 2.49	$ 1.71	$ 1.25	$ 10.07	$ 8.46	$ 3.62
Net income per diluted share (in dollars per share)	$ 2.99	$ 2.69	$ 2.61	$ 1.67	$ 2.96	$ 2.46	$ 1.69	$ 1.23	$ 9.95	$ 8.36	$ 3.58