Cash, Cash Equivalents and Investments (Fair Value of Debt Securities by Contractual Maturity) (Details) - USD ($) $ in Thousands	Aug. 31, 2017	Nov. 30, 2016
Investments and Cash [Abstract]
Due in one year or less	$ 20,881	$ 21,172
Due after one year	25,678	21,546
Total	$ 46,559	$ 42,718