Consolidated Statements of Stockholder's Equity - USD ($) shares in Thousands, $ in Thousands	Total	Cumulative Effect Period of Adoption Adjustment	Net Investment Hedging	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Deficit Cumulative Effect Period of Adoption Adjustment	Accumulated Other Comprehensive Loss	Accumulated Other Comprehensive Loss Net Investment Hedging
Beginning balance at Sep. 30, 2019	$ 1,201,998	$ (1,572)		$ 1,149	$ 1,502,949	$ (191,390)	$ (1,572)	$ (110,710)
Beginning balance (in shares) at Sep. 30, 2019				114,899
Accounting Standards Update [Extensible List]		us-gaap:AccountingStandardsUpdate201602Member					us-gaap:AccountingStandardsUpdate201602Member
Common stock issued for employee stock-based awards				$ 9	(9)
Common stock issued for employee stock-based awards (in shares)				903
Shares surrendered by employees to pay taxes related to stock-based awards	(22,849)			$ (3)	(22,846)
Shares surrendered by employees to pay taxes related to stock-based awards (in shares)				(308)
Compensation expense from stock-based awards	27,936				27,936
Net income	35,455					35,455
Unrealized loss on net investment hedges, net of tax			$ (3,343)						$ (3,343)
Foreign currency translation adjustment	10,147							10,147
Unrealized loss on available-for-sale securities, net of tax	(7)							(7)
Change in pension benefits, net of tax	52							52
Ending balance at Dec. 28, 2019	1,247,817			$ 1,155	1,508,030	(157,507)		(103,861)
Ending balance (in shares) at Dec. 28, 2019				115,494
Beginning balance at Sep. 30, 2020	$ 1,438,248			$ 1,161	1,602,728	(62,267)		(103,374)
Beginning balance (in shares) at Sep. 30, 2020	116,125			116,125
Common stock issued for employee stock-based awards				$ 8	(8)
Common stock issued for employee stock-based awards (in shares)				802
Shares surrendered by employees to pay taxes related to stock-based awards	$ (25,431)			$ (2)	(25,429)
Shares surrendered by employees to pay taxes related to stock-based awards (in shares)				(263)
Compensation expense from stock-based awards	46,088				46,088
Net income	23,515					23,515
Unrealized loss on net investment hedges, net of tax			$ (6,779)						$ (6,779)
Foreign currency translation adjustment	19,975							19,975
Unrealized loss on available-for-sale securities, net of tax	(307)							(307)
Change in pension benefits, net of tax	(380)							(380)
Ending balance at Dec. 31, 2020	$ 1,494,929			$ 1,167	$ 1,623,379	$ (38,752)		$ (90,865)
Ending balance (in shares) at Dec. 31, 2020	116,664			116,664