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 |