Cash, Cash Equivalents and Short-Term Investments (Details 1) (USD $)	3 Months Ended	12 Months Ended
	Feb. 28, 2014 securities	Nov. 29, 2013 securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities in a continuous unrealized loss position for more than twelve months, fair value	$ 600,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year	1	0
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	294,868,000	344,559,000
Available-for-sale securities in a continuous unrealized loss position for less than twelve months, gross unrealized losses	(666,000)	(938,000)
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Less than One Year	155	177
Corporate bonds and commercial paper
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	194,460,000	225,759,000
Available-for-sale securities in a continuous unrealized loss position for less than twelve months, gross unrealized losses	(382,000)	(631,000)
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	94,326,000	105,278,000
Available-for-sale securities in a continuous unrealized loss position for less than twelve months, gross unrealized losses	(280,000)	(283,000)
Municipal 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	6,082,000	13,522,000
Available-for-sale securities in a continuous unrealized loss position for less than twelve months, gross unrealized losses	$ (4,000)	$ (24,000)