Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Jul. 03, 2021	Jun. 27, 2020
CASH FLOWS PROVIDED BY (USED IN) OPERATING ACTIVITIES:
Net income	$ 212,433	$ 88,107
Adjustments to reconcile net income to cash provided by (used in) operating activities:
Depreciation and amortization	82,204	85,663
Stock-based compensation expense	26,147	22,043
Deferred income taxes	32,142	9,852
Goodwill and other asset impairments	0	8,409
Gain on sale of intellectual property	(15,000)	0
Gain on liquidation of foreign entity	(8,263)	0
Other, net	(633)	846
Changes in operating assets and liabilities, net of amounts acquired:
Accounts receivable	(108,277)	84,259
Contract assets	51,487	15,051
Inventories	(22,606)	16,658
Prepaid expenses and other assets	(3,574)	6,167
Accounts payable	61,524	(62,779)
Accrued liabilities	(60,963)	(53,610)
Cash provided by operating activities	246,621	220,666
CASH FLOWS PROVIDED BY (USED IN) INVESTING ACTIVITIES:
Purchases of property, plant and equipment, net of proceeds from asset sales	(42,722)	(53,897)
Purchases of investments	(1,705)	(30,000)
Proceeds from sale of intellectual property	5,000	0
Cash paid for business acquisition, net of cash acquired	(21,408)	0
Cash used in investing activities	(60,835)	(83,897)
CASH FLOWS PROVIDED BY (USED IN) FINANCING ACTIVITIES:
Repayment of Long-term Debt, Long-term Lease Obligation, and Capital Security	(14,064)	(29,674)
Proceeds from revolving credit facility borrowings	399,600	1,909,000
Repayments of revolving credit facility borrowings	(399,600)	(1,259,000)
Net proceeds from stock issuances	2,754	5,448
Repurchases of common stock	(31,426)	(100,100)
Cash provided by (used in) financing activities	(42,736)	525,674
Effect of exchange rate changes	268	33
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect	143,318	662,476
Cash and cash equivalents at beginning of period	480,526	454,741
Cash and cash equivalents at end of period	623,844	1,117,217
Cash paid during the period for:
Interest, net of capitalized interest	4,502	14,305
Income taxes, net of refunds	24,462	18,902
Unpaid purchases of property, plant and equipment at the end of period	$ 26,499	$ 10,578