Cash, Cash Equivalents and Investments (Summary Of Cash, Cash Equivalents And Trading And Available-For-Sale Investments) (Details) - USD ($) $ in Thousands	Feb. 29, 2020	Nov. 30, 2019
Cash, Cash Equivalents and Investments [Line Items]
Cash and cash equivalents	$ 161,094	$ 154,259
Unrealized Gains	98	23
Unrealized Losses	0	0
Total Amortized Cost Basis	176,957	173,662
Total Fair Value	177,055	173,685
State and municipal bond obligations
Cash, Cash Equivalents and Investments [Line Items]
Amortized Cost Basis	3,557	7,036
Unrealized Gains	6	1
Unrealized Losses	0	0
Fair Value	3,563	7,037
U.S. treasury bonds
Cash, Cash Equivalents and Investments [Line Items]
Amortized Cost Basis	5,757	7,221
Unrealized Gains	48	10
Unrealized Losses	0	0
Fair Value	5,805	7,231
Corporate bonds
Cash, Cash Equivalents and Investments [Line Items]
Amortized Cost Basis	6,549	5,146
Unrealized Gains	44	12
Unrealized Losses	0	0
Fair Value	6,593	5,158
Cash
Cash, Cash Equivalents and Investments [Line Items]
Cash and cash equivalents	147,494	144,346
Money market funds
Cash, Cash Equivalents and Investments [Line Items]
Cash and cash equivalents	$ 13,600	$ 9,913