Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Jun. 27, 2020	Jun. 29, 2019
CASH FLOWS PROVIDED BY (USED IN) OPERATING ACTIVITIES:
Net income	$ 88,107	$ 121,758
Adjustments to reconcile net income to cash provided by (used in) operating activities:
Depreciation and amortization	85,663	88,441
Stock-based compensation expense	22,043	20,578
Deferred income taxes	9,852	27,182
Goodwill impairment	8,409	0
Other, net	846	(1,361)
Changes in operating assets and liabilities:
Accounts receivable	84,259	(50,805)
Contract assets	15,051	(11,807)
Inventories	16,658	108,043
Prepaid expenses and other assets	6,167	2,144
Accounts payable	(62,779)	(172,654)
Accrued liabilities	(53,610)	61,249
Cash provided by operating activities	220,666	192,768
CASH FLOWS PROVIDED BY (USED IN) INVESTING ACTIVITIES:
Purchases of property, plant and equipment	(54,787)	(102,025)
Proceeds from sales of property, plant and equipment	890	4,057
Purchases of investments	30,000	499
Cash used in investing activities	(83,897)	(98,467)
CASH FLOWS PROVIDED BY (USED IN) FINANCING ACTIVITIES:
Repayments of long-term debt	29,674	378,416
Proceeds from long-term debt	0	375,000
Proceeds from revolving credit facility borrowings	1,909,000	3,223,525
Repayments of revolving credit facility borrowings	(1,259,000)	(3,317,525)
Debt issuance costs	0	(2,727)
Net proceeds from stock issuances	5,448	12,719
Repurchases of common stock	(100,100)	(12,614)
Cash provided by (used in) financing activities	525,674	(100,038)
Effect of exchange rate changes	33	482
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect	662,476	(5,255)
Cash and cash equivalents at beginning of period	454,741	419,528
Cash and cash equivalents at end of period	1,117,217	414,273
Cash paid during the period for:
Interest, net of capitalized interest	14,305	25,291
Income taxes, net of refunds	18,902	23,767
Unpaid purchases of property, plant and equipment at the end of period	$ 10,578	$ 30,018