Cash, Cash Equivalents and Short-Term Investments (Details 1) (USD $) In Thousands, unless otherwise specified	Mar. 01, 2013 securities	Nov. 30, 2012 securities
Fair Value and Gross Unrealized Losses Related to Available-For-Sale Securities [Abstract]
Available-for-sale securities in a continuous unrealized loss position for less than twelve months, fair value	$ 313,397	$ 186,321
Available-for-sale securities in a continuous unrealized loss position for less than twelve months, gross unrealized losses	(199)	(259)
Available-for-sale securities in a continuous unrealized loss position for more than twelve months, fair value	8,209	2,999
Available-for-sale securities in a continuous unrealized loss position for more than twelve months, gross unrealized losses	(3)	(1)
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Number of securities in a continuous unrealized loss position for less than twelve months	153	65
Number of securities in a continuous unrealized loss position for more than twelve months	1	1
Corporate bonds and commercial paper [Member]
Fair Value and Gross Unrealized Losses Related to Available-For-Sale Securities [Abstract]
Available-for-sale securities in a continuous unrealized loss position for less than twelve months, fair value	191,986	95,489
Available-for-sale securities in a continuous unrealized loss position for less than twelve months, gross unrealized losses	(167)	(132)
Available-for-sale securities in a continuous unrealized loss position for more than twelve months, fair value	0	2,999
Available-for-sale securities in a continuous unrealized loss position for more than twelve months, gross unrealized losses	0	(1)
US Treasury and Government [Member]
Fair Value and Gross Unrealized Losses Related to Available-For-Sale Securities [Abstract]
Available-for-sale securities in a continuous unrealized loss position for less than twelve months, fair value	102,862	48,203
Available-for-sale securities in a continuous unrealized loss position for less than twelve months, gross unrealized losses	(19)	(55)
Available-for-sale securities in a continuous unrealized loss position for more than twelve months, fair value	8,209	0
Available-for-sale securities in a continuous unrealized loss position for more than twelve months, gross unrealized losses	(3)	0
Foreign government securities [Member]
Fair Value and Gross Unrealized Losses Related to Available-For-Sale Securities [Abstract]
Available-for-sale securities in a continuous unrealized loss position for less than twelve months, fair value	3,599	2,105
Available-for-sale securities in a continuous unrealized loss position for less than twelve months, gross unrealized losses	(1)	(12)
Municipal securities [Member]
Fair Value and Gross Unrealized Losses Related to Available-For-Sale Securities [Abstract]
Available-for-sale securities in a continuous unrealized loss position for less than twelve months, fair value	14,950	40,524
Available-for-sale securities in a continuous unrealized loss position for less than twelve months, gross unrealized losses	$ (12)	$ (60)