Cash, Cash Equivalents and Investments (Investments with Continuous Unrealized Losses and Their Related Fair Values) (Details) (USD $) In Thousands, unless otherwise specified	Nov. 30, 2013
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less Than 12 Months	$ 0
Unrealized Losses, Less Than 12 Months	0
Fair Value, 12 Months or Greater	24,761
Unrealized Losses, 12 Months or Greater	(3,989)
Total, Fair Value	24,761
Total, Unrealized Losses	(3,989)
Auction rate securities - municipal bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less Than 12 Months	0
Unrealized Losses, Less Than 12 Months	0
Fair Value, 12 Months or Greater	21,933
Unrealized Losses, 12 Months or Greater	(3,317)
Total, Fair Value	21,933
Total, Unrealized Losses	(3,317)
Auction rate securities - student loans [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less Than 12 Months	0
Unrealized Losses, Less Than 12 Months	0
Fair Value, 12 Months or Greater	2,828
Unrealized Losses, 12 Months or Greater	(672)
Total, Fair Value	2,828
Total, Unrealized Losses	$ (672)