Cash, Cash Equivalents and Investments (Summary Of Cash, Cash Equivalents And Trading And Available-For-Sale Investments) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Nov. 30, 2013	Nov. 30, 2012
Cash, Cash Equivalents and Investments [Line Items]
Amortized Cost Basis	$ 260,406	$ 385,640
Realized Losses	(380)
Unrealized Gains	164	255
Unrealized Losses	(3,989)	(4,357)
Fair Value	256,201	381,538
State And Municipal Bond Obligations [Member]
Cash, Cash Equivalents and Investments [Line Items]
Amortized Cost Basis	30,938	50,565
Realized Losses	0
Unrealized Gains	164	255
Unrealized Losses	0	(2)
Fair Value	31,102	50,818
Auction Rate Securities - Municipal Bonds [Member]
Cash, Cash Equivalents and Investments [Line Items]
Amortized Cost Basis	27,150	27,175
Realized Losses	(380)
Unrealized Gains	0	0
Unrealized Losses	(3,317)	(3,755)
Fair Value	23,453	23,420
Auction Rate Securities - Student Loans [Member]
Cash, Cash Equivalents and Investments [Line Items]
Amortized Cost Basis	3,500	3,500
Realized Losses	0
Unrealized Gains	0	0
Unrealized Losses	(672)	(599)
Fair Value	2,828	2,901
Corporate Bonds [Member]
Cash, Cash Equivalents and Investments [Line Items]
Amortized Cost Basis		2,608
Unrealized Gains		0
Unrealized Losses		(1)
Fair Value		2,607
Cash [Member]
Cash, Cash Equivalents and Investments [Line Items]
Amortized Cost Basis	144,305	176,201
Fair Value	144,305	176,201
Money Market Funds [Member]
Cash, Cash Equivalents and Investments [Line Items]
Amortized Cost Basis	54,513	125,591
Fair Value	$ 54,513	$ 125,591