Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Sep. 24, 2021	Sep. 25, 2020	Sep. 27, 2019
Operating activities:
Net income including controlling interest	$ 317,823	$ 231,619	$ 255,505
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	95,860	90,878	85,123
Stock-based compensation	99,698	86,628	76,580
Amortization of operating lease right-of-use assets	16,897	21,006	0
Amortization of premium on investments	1,373	800	358
Provision for doubtful accounts	(2,889)	7,689	4,523
Deferred income taxes	(37,048)	(5,274)	(40,191)
Gain on sale of assets	(13,871)	0	0
Other non-cash items affecting net income	(5,452)	10,920	6,952
Changes in operating assets and liabilities:
Accounts receivable	(49,034)	1,251	(27,492)
Contract assets	(21,154)	34,297	(29,708)
Inventories	17,154	(11,784)	(16,098)
Operating lease right-of-use assets	(5,199)	(34,522)	0
Prepaid expenses and other assets	17,165	(5,680)	(6,200)
Accounts payable and other liabilities	44,230	(43,545)	33,420
Income taxes, net	(2,975)	(50,586)	(2,186)
Contract liabilities	2,361	(4,621)	1,084
Operating lease liabilities	(11,369)	15,618	0
Other non-current liabilities	(15,817)	(845)	(13,996)
Net cash provided by operating activities	447,753	343,849	327,674
Investing activities:
Purchases of investment securities	(67,101)	(287,777)	(265,361)
Proceeds from sales of investment securities	10,892	244,517	200,636
Proceeds from maturities of available-for-sale securities	53,893	246,621	136,951
Purchases of property, plant and equipment	(54,454)	(66,347)	(96,281)
Proceeds from sale of assets	16,365	0	0
Acquisitions, net of cash acquired	(4,500)	0	(14,919)
Purchase of intangible assets	0	(2,640)	(17,255)
Net cash provided by/(used in) investing activities	(44,905)	134,374	(56,229)
Financing activities:
Proceeds from issuance of common stock	122,088	82,658	57,346
Repurchase of common stock	(245,864)	(173,742)	(340,585)
Payment of cash dividend	(89,172)	(88,581)	(77,496)
Distribution to controlling interest	(7,362)	(283)	(1,015)
Shares repurchased for tax withholdings on vesting of restricted stock	(32,205)	(23,065)	(22,788)
Payment related to prior purchases of intangible assets	0	(91)	0
Payments for Deferred Consideration	0	4,671	743
Net cash used in financing activities	(252,515)	(207,775)	(385,281)
Effect of foreign exchange rate changes on cash and cash equivalents	2,720	3,938	(5,821)
Net increase/(decrease) in cash, cash equivalents, and restricted cash	153,053	274,386	(119,657)
Cash, cash equivalents, and restricted cash at beginning of period	1,079,979	805,593	925,250
Cash, cash equivalents, and restricted cash at end of period	1,233,032	1,079,979	805,593
Supplemental disclosure:
Cash paid for income taxes, net of refunds received	70,737	52,869	59,722
Non-cash investing activities:
Change in property, plant, and equipment purchased, unpaid at period-end	2,772	(3,417)	(324)
Purchase consideration payable for acquisition	500	0	1,700
Purchase consideration payable for intangible assets	$ 30	$ 260	$ 1,881