Cash, Cash Equivalents and Investments (Summary Of Cash, Cash Equivalents And Trading And Available-For-Sale Investments) (Details) - USD ($) $ in Thousands	Nov. 30, 2015	Nov. 30, 2014
Cash, Cash Equivalents and Investments [Line Items]
Amortized Cost Basis	$ 241,276	$ 283,182
Unrealized Gains	30	86
Unrealized Losses	(27)	0
Fair Value	241,279	283,268
State And Municipal Bond Obligations [Member]
Cash, Cash Equivalents and Investments [Line Items]
Amortized Cost Basis	20,387	20,100
Unrealized Gains	30	86
Unrealized Losses	0	0
Fair Value	20,417	20,186
US Treasury Bonds [Member]
Cash, Cash Equivalents and Investments [Line Items]
Amortized Cost Basis	3,109
Unrealized Gains	0
Unrealized Losses	(15)
Fair Value	3,094
US Government Agency Bonds [Member]
Cash, Cash Equivalents and Investments [Line Items]
Amortized Cost Basis	1,645
Unrealized Gains	0
Unrealized Losses	(4)
Fair Value	1,641
Corporate Bonds [Member]
Cash, Cash Equivalents and Investments [Line Items]
Amortized Cost Basis	3,756
Unrealized Gains	0
Unrealized Losses	(8)
Fair Value	3,748
Cash [Member]
Cash, Cash Equivalents and Investments [Line Items]
Amortized Cost Basis	186,241	195,189
Fair Value	186,241	195,189
Money Market Funds [Member]
Cash, Cash Equivalents and Investments [Line Items]
Amortized Cost Basis	26,138	67,893
Fair Value	$ 26,138	$ 67,893