Revenue Recognition - Cash Flow Statement Impact of Adoption of ASC 606 (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 30, 2018	Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net income	$ 42,032	$ 46,052
Accounts receivable and contract assets	14,528	(36,011)
Contract liabilities	6,090	12,330
Income taxes receivable/payable	12,015	7,926
Net cash used in operating activities	(15,302)	$ (57,682)
Recognition Under Previous Guidance
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net income	40,354
Accounts receivable and contract assets	7,574
Contract liabilities	15,248
Income taxes receivable/payable	11,489
Net cash used in operating activities	(15,302)
Impact of the Adoption of ASC 606 | Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net income	1,678
Accounts receivable and contract assets	6,954
Contract liabilities	(9,158)
Income taxes receivable/payable	526
Net cash used in operating activities	$ 0