v2.4.0.6
Cash, Cash Equivalents And Investments (Investments With Continuous Unrealized Losses And Their Related Fair Values) (Details) (USD $)
In Thousands, unless otherwise specified
Feb. 29, 2012
Nov. 30, 2011
Schedule of Available-for-sale Securities [Line Items]    
Fair Value, Less Than 12 Months $ 13,200 $ 24,585
Unrealized Losses, Less Than 12 Months (6) (16)
Fair Value, 12 Months or Greater 33,343 33,539
Unrealized Losses, 12 Months or Greater (6,332) (6,361)
Total, Fair Value 46,543 58,124
Total, Unrealized Losses (6,338) (6,377)
State And Municipal Bond Obligations [Member]
    
Schedule of Available-for-sale Securities [Line Items]    
Fair Value, Less Than 12 Months 9,347 24,585
Unrealized Losses, Less Than 12 Months (5) (16)
Total, Fair Value 9,347 24,585
Total, Unrealized Losses (5) (16)
Auction Rate Securities - Municipal Bonds [Member]
    
Schedule of Available-for-sale Securities [Line Items]    
Fair Value, 12 Months or Greater 22,966 22,931
Unrealized Losses, 12 Months or Greater (4,209) (4,269)
Total, Fair Value 22,966 22,931
Total, Unrealized Losses (4,209) (4,269)
Auction Rate Securities - Student Loans [Member]
    
Schedule of Available-for-sale Securities [Line Items]    
Fair Value, 12 Months or Greater 10,377 10,608
Unrealized Losses, 12 Months or Greater (2,123) (2,092)
Total, Fair Value 10,377 10,608
Total, Unrealized Losses (2,123) (2,092)
Corporate Bonds [Member]
    
Schedule of Available-for-sale Securities [Line Items]    
Fair Value, Less Than 12 Months 3,853  
Unrealized Losses, Less Than 12 Months (1)  
Total, Fair Value 3,853  
Total, Unrealized Losses $ (1)