Cash, Cash Equivalents and Investments (Summary Of Cash, Cash Equivalents And Trading And Available-For-Sale Investments) (Details) - USD ($) $ in Thousands	May. 31, 2015	Nov. 30, 2014
Cash, Cash Equivalents and Investments [Line Items]
Amortized Cost Basis	$ 199,070	$ 283,182
Unrealized Gains	63	86
Unrealized Losses	(12)	0
Fair Value	199,121	283,268
State and municipal bond obligations [Member]
Cash, Cash Equivalents and Investments [Line Items]
Amortized Cost Basis	33,050	20,100
Unrealized Gains	63	86
Unrealized Losses	(12)	0
Fair Value	33,101	20,186
Cash [Member]
Cash, Cash Equivalents and Investments [Line Items]
Amortized Cost Basis	144,175	195,189
Fair Value	144,175	195,189
Money market funds [Member]
Cash, Cash Equivalents and Investments [Line Items]
Amortized Cost Basis	21,845	67,893
Fair Value	$ 21,845	$ 67,893