Cash, Cash Equivalents and Investments (Fair Value of Debt Securities by Contractual Maturity) (Details) (USD $) In Thousands, unless otherwise specified					12 Months Ended
	Nov. 30, 2013		Nov. 30, 2012		Nov. 30, 2013 Minimum [Member]	Nov. 30, 2013 Maximum [Member]
Cash, Cash Equivalents and Investments [Line Items]
Due in one year or less	$ 42,198	[1]	$ 55,001	[1]
Due after one year	15,185	[2]	24,745	[2]
Total	$ 57,383		$ 79,746
Remaining contractual maturities of investments					10 years	29 years

[1] Includes ARS which are tendered for interest-rate setting purposes periodically throughout the year. Beginning in February 2008, auctions for these securities began to fail, and therefore these investments currently lack short-term liquidity. The remaining contractual maturities of these securities range from 10 to 29 years.

[2] Includes state and municipal bond obligations, which are securities representing investments available for current operations and are classified as current in the consolidated balance sheets.