Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Sep. 28, 2018	Sep. 29, 2017	Sep. 30, 2016
Operating activities:
Net income including controlling interest	$ 122,805	$ 202,427	$ 186,402
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	81,283	84,308	85,152
Stock-based compensation	71,249	65,343	66,985
Amortization of premium on investments	2,473	2,758	3,824
Provision for doubtful accounts	2,507	924	1,017
Deferred income taxes	89,934	(29,368)	(22,798)
Other non-cash items affecting net income	7,570	2,886	1,779
Changes in operating assets and liabilities:
Accounts receivable	(65,723)	1,041	24,886
Inventories	(6,602)	(11,922)	(2,949)
Prepaid expenses and other assets	(14,895)	(12,411)	(15,217)
Accounts payable and other liabilities	15,690	44,453	2,834
Income taxes, net	39,738	26,950	17,265
Deferred revenue	4,362	23	10,288
Other non-current liabilities	1,811	381	596
Net cash provided by operating activities	352,202	377,793	360,064
Investing activities:
Purchases of available-for-sale securities	(174,195)	(289,530)	(426,118)
Proceeds from sales of available-for-sale securities	123,058	84,047	262,125
Proceeds from maturities of available-for-sale securities	237,432	152,324	103,987
Purchases of property, plant and equipment	(72,814)	(99,617)	(100,762)
Acquisitions, net of cash acquired	(22,852)	0	0
Purchases of intangible assets	(12,543)	(5,250)	(121,020)
Change in restricted cash	164	(3,706)	(709)
Net cash provided by/(used in) investing activities	78,250	(161,732)	(282,497)
Financing activities:
Proceeds from issuance of common stock	106,162	69,998	71,111
Repurchase of common stock	(150,470)	(100,000)	(100,854)
Payment of cash dividend	(66,155)	(57,059)	(48,397)
Distribution to controlling interest	(1,022)	(2,094)	(214)
Shares repurchased for tax withholdings on vesting of restricted stock	(22,144)	(17,676)	(13,632)
Net cash used in financing activities	(133,629)	(106,831)	(91,986)
Effect of foreign exchange rate changes on cash and cash equivalents	(5,777)	1,675	(1,395)
Net increase/(decrease) in cash and cash equivalents	291,046	110,905	(15,814)
Cash and cash equivalents at beginning of period	627,017	516,112	531,926
Cash and cash equivalents at end of period	918,063	627,017	516,112
Supplemental disclosure:
Cash paid for income taxes, net of refunds received	60,875	56,760	55,085
Non-cash investing activities:
Change in PP&E purchases unpaid at period-end	7,990	(9,613)	(7,233)
Purchase consideration payable for acquisition	$ 3,750	$ 0	$ 0