CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Sep. 28, 2019	Sep. 29, 2018	Sep. 30, 2017
Statement of Cash Flows [Abstract]
Interest Paid, Excluding Capitalized Interest, Operating Activities	$ 1,634	$ 1,054	$ 1,059
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	11,653	56,676	126,099
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	20,304	19,015	16,257
Impairment charges	0	0	35,207
Equity-based compensation and employee benefits	14,332	11,685	11,722
(Excess tax benefits) / Reversal of excess tax benefits from stock based compensation	0	(50)	4,392
Adjustment for doubtful accounts	212	383	(136)
Adjustment for inventory valuation	2,657	4,897	10,925
Deferred taxes	8,825	22,519	(16,758)
Gain/(loss) on disposal of property, plant and equipment	20	(676)	(999)
Unrealized foreign currency translation	(3,325)	(2,002)	1,362
Share of results of equity-method investee	124	129	(190)
Changes in operating assets and liabilities, net of assets and liabilities assumed in businesses combinations:
Accounts and notes receivable	47,395	(45,154)	(67,879)
Inventory	24,105	1,631	(47,425)
Prepaid expenses and other current assets	(490)	9,405	(8,468)
Accounts payable, accrued expenses and other current liabilities	(53,759)	(30,868)	63,425
Income taxes payable	(7,758)	77,968	3,946
Other, net	1,672	(2,059)	4,830
Net cash provided by operating activities	65,967	123,499	136,310
CASH FLOWS FROM INVESTING ACTIVITIES:
Acquisition of business, net of cash acquired	0	0	(27,119)
Purchases of property, plant and equipment	(11,742)	(20,496)	(25,590)
Proceeds from sales of property, plant and equipment	210	625	1,352
Purchase of equity investments	(5,000)	0	(1,312)
Purchase of short term investments	(619,000)	(684,000)	(305,000)
Maturity of short term investments	683,000	607,000	213,000
Net cash provided by / (used in) investing activities	47,468	(96,871)	(144,669)
CASH FLOWS FROM FINANCING ACTIVITIES:
Payment on debts	(30,773)	(704)	(604)
Proceeds from exercise of common stock options	14	55	509
Repurchase of common stock	(99,897)	(90,310)	(18,197)
(Reversal of excess tax benefits) / Excess tax benefits from stock based compensation	0	0	(4,392)
Proceeds from short term debt	90,904	0	0
Common stock cash dividends paid	(31,566)	(8,176)	0
Net cash used in financing activities	(71,318)	(99,135)	(22,684)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	919	715	76
Changes in cash, cash equivalents and restricted cash	43,036	(71,792)	(30,967)
Cash, cash equivalents and restricted cash at beginning of period	321,148	392,940	423,907
Cash, cash equivalents and restricted cash at end of period	364,184	321,148	392,940
CASH PAID FOR:
Income taxes	$ 22,073	$ 13,179	$ 8,283