CASH, CASH EQUIVALENTS, RESTRICTED CASH AND SHORT-TERM INVESTMENTS (Details) - USD ($) $ in Thousands		Mar. 28, 2020		Sep. 28, 2019
Cash, Cash Equivalents, Restricted Cash and Short-Term Investments [Line Items]
Cash		$ 225,849		$ 201,005
Cash and Cash Equivalents, Amortized Cost		392,307		364,184
Cash and Cash Equivalents, Unrealized Gain		0		0
Cash and Cash Equivalents, Unrealized Loss		0		0
Cash and Cash Equivalents, Estimated Fair Value		392,307		364,184
Short-term investments	[1]	248,000		229,000
Short-term Investments, Unrealized Gain		0		0
Short-term Investments, Unrealized Loss		0		0
Short-term Investments, Estimated Fair Value		248,000		229,000
Cash, Cash Equivalents, Restricted Cash, Restricted Cash Equivalents, and Short-Term Investments, Amortized Cost		640,307		593,184
Cash, Cash Equivalents, Restricted Cash, Restricted Cash Equivalents, and Short-Term Investments, Unrealized Gain		0		0
Cash, Cash Equivalents, Restricted Cash, Restricted Cash Equivalents, and Short-Term Investments, Unrealized Loss		0		0
Cash, Cash Equivalents, Restricted Cash, Restricted Cash Equivalents, and Short-Term Investments, Estimated Fair Value		640,307		593,184
Money market funds
Cash, Cash Equivalents, Restricted Cash and Short-Term Investments [Line Items]
Cash Equivalents, Amortized Cost		166,451		163,172
Cash Equivalents, Unrealized Gain		0		0
Cash Equivalents, Unrealized Loss		0		0
Cash Equivalents, Estimated Fair Value		166,451	[2]	163,172	[3]
Time deposits
Cash, Cash Equivalents, Restricted Cash and Short-Term Investments [Line Items]
Cash Equivalents, Amortized Cost		7		7
Cash Equivalents, Unrealized Gain		0		0
Cash Equivalents, Unrealized Loss		0		0
Cash Equivalents, Estimated Fair Value		7	[4]	7	[5]
Short-term investments		149,000		130,000
Short-term Investments, Unrealized Gain		0		0
Short-term Investments, Unrealized Loss		0		0
Short-term Investments, Estimated Fair Value		149,000	[4]	130,000	[3]
Deposits
Cash, Cash Equivalents, Restricted Cash and Short-Term Investments [Line Items]
Short-term investments		99,000	[6]	99,000	[7]
Short-term Investments, Unrealized Gain		0		0
Short-term Investments, Unrealized Loss		0		0
Short-term Investments, Estimated Fair Value		$ 99,000	[4],[6]	$ 99,000	[5],[7]

[1] All short-term investments were classified as available-for-sale and were measured at fair value based on level one measurement, or quoted market prices, as defined by ASC 820. The Company did not recognize any realized gains or losses on the sale of investments during the three and six months ended March 28, 2020 and March 30, 2019.

[2] The fair value was determined using unadjusted prices in active, accessible markets for identical assets, and as such they were classified as Level 1 assets in the fair value hierarchy.

[3] The fair value was determined using unadjusted prices in active, accessible markets for identical assets, and as such they were classified as Level 1 assets in the fair value hierarchy.

[4] Fair value approximates cost basis.

[5] Fair value approximates cost basis.

[6] Represents deposits that require a notice period of three months for withdrawal.

[7] Represents deposits that require a notice period of three months for withdrawal.