Short-Term And Long-Term Investments (Schedule Of Investments That Have Been In A Continuous Unrealized Loss Position) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Continuous Loss Position, Unrealized Loss, Less Than 12 Months	$ 369,443
Available-For-Sale Securities, Continuous Unrealized Loss Position, Less Than 12 Months, Aggregate Losses Accumulated In Investments	(1,002)
Fair Value, Continuous Loss Position, Unrealized Loss, 12 Months or Greater	34,779
Available-For-Sale Securities, Continuous Unrealized Loss Position, 12 Months Or Longer, Aggregate Losses Accumulated In Investments	(43)
Fair Value, Continuous Loss Position, Unrealized Loss, Total	404,222
Available-For-Sale Securities, Continuous Unrealized Loss Position, Aggregate Losses Accumulated In Investments	(1,045)
Corporate Bonds And Notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Continuous Loss Position, Unrealized Loss, Less Than 12 Months	262,771
Available-For-Sale Securities, Continuous Unrealized Loss Position, Less Than 12 Months, Aggregate Losses Accumulated In Investments	(848)
Fair Value, Continuous Loss Position, Unrealized Loss, 12 Months or Greater	7,804
Available-For-Sale Securities, Continuous Unrealized Loss Position, 12 Months Or Longer, Aggregate Losses Accumulated In Investments	(10)
Fair Value, Continuous Loss Position, Unrealized Loss, Total	270,575
Available-For-Sale Securities, Continuous Unrealized Loss Position, Aggregate Losses Accumulated In Investments	(858)
Municipal Bonds And Notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Continuous Loss Position, Unrealized Loss, Less Than 12 Months	14,649
Available-For-Sale Securities, Continuous Unrealized Loss Position, Less Than 12 Months, Aggregate Losses Accumulated In Investments	(10)
Fair Value, Continuous Loss Position, Unrealized Loss, 12 Months or Greater	0
Available-For-Sale Securities, Continuous Unrealized Loss Position, 12 Months Or Longer, Aggregate Losses Accumulated In Investments	0
Fair Value, Continuous Loss Position, Unrealized Loss, Total	14,649
Available-For-Sale Securities, Continuous Unrealized Loss Position, Aggregate Losses Accumulated In Investments	(10)
U.S. Government Agency Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Continuous Loss Position, Unrealized Loss, Less Than 12 Months	89,464
Available-For-Sale Securities, Continuous Unrealized Loss Position, Less Than 12 Months, Aggregate Losses Accumulated In Investments	(135)
Fair Value, Continuous Loss Position, Unrealized Loss, 12 Months or Greater	26,975
Available-For-Sale Securities, Continuous Unrealized Loss Position, 12 Months Or Longer, Aggregate Losses Accumulated In Investments	(33)
Fair Value, Continuous Loss Position, Unrealized Loss, Total	116,439
Available-For-Sale Securities, Continuous Unrealized Loss Position, Aggregate Losses Accumulated In Investments	(168)
Foreign Government Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Continuous Loss Position, Unrealized Loss, Less Than 12 Months	2,559
Available-For-Sale Securities, Continuous Unrealized Loss Position, Less Than 12 Months, Aggregate Losses Accumulated In Investments	(9)
Fair Value, Continuous Loss Position, Unrealized Loss, 12 Months or Greater	0
Available-For-Sale Securities, Continuous Unrealized Loss Position, 12 Months Or Longer, Aggregate Losses Accumulated In Investments	0
Fair Value, Continuous Loss Position, Unrealized Loss, Total	2,559
Available-For-Sale Securities, Continuous Unrealized Loss Position, Aggregate Losses Accumulated In Investments	$ (9)