Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Dec. 28, 2019	Dec. 29, 2018
CASH FLOWS PROVIDED BY (USED IN) OPERATING ACTIVITIES:
Net income	$ 38,345	$ 37,952
Adjustments to reconcile net income to cash provided by (used in) operating activities:
Depreciation and amortization	28,735	29,792
Stock-based compensation expense	6,906	5,816
Deferred income taxes	3,005	11,583
Other, net	(322)	353
Changes in operating assets and liabilities:
Accounts receivable	65,449	(160,974)
Contract assets	(25,560)	(43,998)
Inventories	57,357	(30,708)
Prepaid expenses and other assets	2,372	3,033
Accounts payable	(139,304)	(2,845)
Accrued liabilities	(15,812)	71,560
Cash provided by (used in) operating activities	21,171	(78,436)
CASH FLOWS PROVIDED BY (USED IN) INVESTING ACTIVITIES:
Purchases of property, plant and equipment	(28,466)	(37,166)
Proceeds from sales of property, plant and equipment	420	575
Cash used in investing activities	(28,046)	(36,591)
CASH FLOWS PROVIDED BY (USED IN) FINANCING ACTIVITIES:
Repayments of long-term debt	4,688	0
Proceeds from revolving credit facility borrowings	717,000	1,043,825
Repayments of revolving credit facility borrowings	(717,000)	(928,825)
Debt issuance costs	0	(2,003)
Net proceeds from stock issuances	4,852	3,568
Repurchases of common stock	(17,550)	(11,842)
Cash provided by (used in) financing activities	(17,386)	104,723
Effect of exchange rate changes	84	66
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect	(24,177)	(10,238)
Cash and cash equivalents at beginning of period	454,741	419,528
Cash and cash equivalents at end of period	430,564	409,290
Cash paid during the period for:
Interest, net of capitalized interest	4,725	10,895
Income taxes, net of refunds	4,888	4,923
Unpaid purchases of property, plant and equipment at the end of period	$ 15,782	$ 41,910