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Investments & Fair Value Measurements (Schedule Of Financial Assets and Liabilities Carried At Fair Value) (Details) - USD ($) $ in Thousands | 6 Months Ended |
--- | --- | ---
Apr. 01, 2016 | Sep. 25, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Document Period End Date | Apr. 01, 2016 |
Cash and Cash Equivalents, Fair Value Disclosure | $ 521,202 | $ 531,926
Available-for-sale Debt Securities, Amortized Cost Basis | 394,280 | 476,407
Available-for-sale Securities, Debt Securities | 395,041 | 476,419
Available-for-sale Securities | 268,091 | 321,015
Investment Owned, at Cost | 892,289 | 991,104
Investment Owned, Unrecognized Unrealized Appreciation | 1,579 | 1,218
Investment Owned, Unrecognized Unrealized Depreciation | (308) | (480)
Cash Cash Equivalents And Investments Total | 893,560 | 991,842
Financial assets carried at fair value |  | 531,926
Contingent Consideration Classified as Equity, Fair Value Disclosure | 95 | 95
Restricted Cash and Cash Equivalents | 5,278 | 2,936
Long-term investments | 268,091 | 321,015
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value | 119,640 | 202,515
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss | (308) | (480)
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Amortized Cost Basis | 130,547 | 158,957
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value | 130,505 | 159,090
Available For Sale Securities Debt Maturities After One Through Two Years Amortized Cost | 125,706 | 173,571
Available For Sale Securities Debt Maturities After One Through Two Years Fair Value | 125,932 | 173,577
Available For Sale Securities Debt Maturities After Two Through Three Years Amortized Cost | 138,027 | 143,879
Available For Sale Securities Debt Maturities After Two Through Three Years Fair Value | 138,604 | 143,752
Level 1 [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and Cash Equivalents, Fair Value Disclosure | 26,238 | 19,014
Investments, Fair Value Disclosure |  | 2,001
Investments, Noncurrent, Fair Value Disclosure | 26,730 | 33,233
Financial assets carried at fair value | 52,968 | 54,248
Level 2 [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and Cash Equivalents, Fair Value Disclosure |  | 1,176
Investments, Fair Value Disclosure | 104,267 | 136,900
Investments, Noncurrent, Fair Value Disclosure | 238,315 | 284,821
Financial assets carried at fair value | 342,582 | 422,897
Level 3 [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Contingent Consideration Classified as Equity, Fair Value Disclosure | 95 | 95
Cash [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and Cash Equivalents, Fair Value Disclosure | 494,964 | 511,736
Money Market Funds [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and Cash Equivalents, Fair Value Disclosure | 26,238 | 19,014
Money Market Funds [Member] | Level 1 [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and Cash Equivalents, Fair Value Disclosure | 26,238 | 19,014
Certificates of Deposit [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Available-for-sale Securities, Amortized Cost Basis | 13,000 |
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax | 0 |
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax | (15) |
Available-for-sale Securities | 12,985 |
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value | 12,986 | 0
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss | (15) | 0
Certificates of Deposit [Member] | Level 2 [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Investments, Noncurrent, Fair Value Disclosure | 12,985 |
U.S. Agency Securities [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Available-for-sale Debt Securities, Amortized Cost Basis |  | 2,000
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax |  | 1
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax |  | 0
Available-for-sale Securities, Debt Securities |  | 2,001
Available-for-sale Securities, Amortized Cost Basis | 11,631 | 1,999
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax | 39 | 1
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax | (1) | 0
Available-for-sale Securities | 11,669 | 2,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value | 2,996 | 19,005
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss | (2) | (17)
U.S. Agency Securities [Member] | Level 1 [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Investments, Fair Value Disclosure |  | 2,001
Investments, Noncurrent, Fair Value Disclosure | 11,669 | 2,000
Government Bonds [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Available-for-sale Securities, Amortized Cost Basis | 14,483 | 30,505
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax | 70 | 19
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax | (1) | (17)
Available-for-sale Securities | 14,552 | 30,507
Government Bonds [Member] | Level 1 [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Investments, Noncurrent, Fair Value Disclosure | 14,552 | 30,507
Commercial Paper [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Available-for-sale Debt Securities, Amortized Cost Basis | 13,867 | 6,478
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax | 22 | 0
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax | (7) | 0
Available-for-sale Securities, Debt Securities | 13,882 | 6,478
Investment Owned, at Cost | 13,860 | 0
Investment Owned, Unrecognized Unrealized Appreciation | 7 | 0
Commercial Paper [Member] | Level 2 [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Investments, Fair Value Disclosure | 13,882 | 6,478
Corporate Bonds [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and Cash Equivalents, Fair Value Disclosure |  | 1,176
Available-for-sale Debt Securities, Amortized Cost Basis | 71,851 | 86,543
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax | 0 | 46
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax | (51) | (11)
Available-for-sale Securities, Debt Securities | 71,800 | 86,578
Available-for-sale Securities, Amortized Cost Basis | 189,585 | 167,394
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax | 810 | 138
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax | (197) | (392)
Available-for-sale Securities | 190,198 | 167,140
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value | 71,460 | 148,034
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss | (248) | (403)
Corporate Bonds [Member] | Level 1 [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Investments, Fair Value Disclosure |  | 1,176
Corporate Bonds [Member] | Level 2 [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Investments, Fair Value Disclosure | 71,800 | 86,578
Investments, Noncurrent, Fair Value Disclosure | 190,198 | 167,140
Municipal Bonds [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Available-for-sale Debt Securities, Amortized Cost Basis | 18,591 | 43,746
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax | 8 | 98
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax | (14) | 0
Available-for-sale Securities, Debt Securities | 18,585 | 43,844
Available-for-sale Securities, Amortized Cost Basis | 35,033 | 117,552
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax | 121 | 189
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax | (22) | (60)
Available-for-sale Securities | 35,132 | 117,681
Investment Owned, at Cost | 18,338 | 35,476
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss | (36) | (60)
Municipal Bonds [Member] | Level 2 [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Investments, Fair Value Disclosure | 18,585 | 43,844
Investments, Noncurrent, Fair Value Disclosure | 35,132 | 117,681
Short-term Investments [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Available-for-sale Debt Securities, Amortized Cost Basis | 104,309 | 138,767
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax | 30 | 145
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax | (72) | (11)
Available-for-sale Securities, Debt Securities | 104,267 | 138,901
Other Long-term Investments [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Available-for-sale Securities, Amortized Cost Basis | 3,046 | 2,961
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax | 509 | 726
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax | 0 | 0
Available-for-sale Securities | 3,555 | 3,687
Investments, Noncurrent, Fair Value Disclosure | 600 | 500
Cost Method Investment, Fair Value Measurement Adjustment | 500 | 700
Other Long-term Investments [Member] | Level 1 [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Investments, Noncurrent, Fair Value Disclosure | 509 | 726
Long-term Investments [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Available-for-sale Securities, Amortized Cost Basis | 266,778 | 320,411
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax | 1,549 | 1,073
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax | (236) | (469)
Investments Held In Supplemental Retirement Plan [Member] | Level 1 [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Financial assets carried at fair value | 2,404 | 2,498
Financial liabilities carried at fair value | 2,404 | 2,498
Cost Method Investment 1 [Member] | Other Long-term Investments [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Long-term investments | 2,000 | 2,000
Cost Method Investment 2 [Member] | Other Long-term Investments [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Long-term investments | $ 500 | $ 500

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- Definition This item represents the cost of debt securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27161-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.2) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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- Definition This item represents the aggregate fair value of investments in debt and equity securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position for less than twelve months. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27337-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27290-111563 + Details
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