Revenue Recognition - Cash Flow Statement Impact of Adoption of ASC 606 (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net income	$ 49,251	$ 33,345	$ 147,227	$ 108,144
Accounts receivable and contract assets			(41,299)	(58,713)
Contract liabilities			(1,946)	35,666
Income taxes receivable/payable			(4,913)	(1,149)
Net cash provided by operating activities			113,385	$ 76,272
Recognition Under Previous Guidance
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net income			146,749
Accounts receivable and contract assets			(54,018)
Contract liabilities			11,433
Income taxes receivable/payable			(5,095)
Net cash provided by operating activities			113,385
Impact of the Adoption of ASC 606 | Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net income			478
Accounts receivable and contract assets			12,719
Contract liabilities			(13,379)
Income taxes receivable/payable			182
Net cash provided by operating activities			$ 0