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Composition Of Certain Financial Statement Captions (Schedule Of Investment Portfolio Recorded As Cash Equivalents, Short-Term Investments, And Long-Term Investments) (Details) (USD $)
In Thousands, unless otherwise specified |
Mar. 30, 2012
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Sep. 30, 2011
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|---|---|---|
| Investment Holdings [Line Items] | ||
| Amortized Cost | $ 823,518 | $ 820,030 |
| Unrealized Gains | 1,443 | 1,632 |
| Unrealized Losses | (56) | (546) |
| Estimated Fair Value | 824,905 | 821,116 |
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U.S. Agency Securities [Member]
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| Investment Holdings [Line Items] | ||
| Amortized Cost | 25,054 | 29,858 |
| Unrealized Gains | 38 | 65 |
| Unrealized Losses | 0 | (4) |
| Estimated Fair Value | 25,092 | 29,919 |
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Municipal debt securities [Member]
|
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| Investment Holdings [Line Items] | ||
| Amortized Cost | 388,574 | 471,005 |
| Unrealized Gains | 840 | 1,251 |
| Unrealized Losses | (43) | (55) |
| Estimated Fair Value | 389,371 | 472,201 |
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Corporate Bonds [Member]
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| Investment Holdings [Line Items] | ||
| Amortized Cost | 124,540 | 177,129 |
| Unrealized Gains | 565 | 316 |
| Unrealized Losses | (13) | (487) |
| Estimated Fair Value | 125,092 | 176,958 |
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Money Market Funds [Member]
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| Investment Holdings [Line Items] | ||
| Amortized Cost | 264,366 | 142,038 |
| Unrealized Gains | 0 | 0 |
| Unrealized Losses | 0 | 0 |
| Estimated Fair Value | 264,366 | 142,038 |
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Commercial Paper [Member]
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| Investment Holdings [Line Items] | ||
| Amortized Cost | 20,984 | |
| Unrealized Gains | 0 | |
| Unrealized Losses | 0 | |
| Estimated Fair Value | $ 20,984 |