Cash, Cash Equivalents and Investments (Summary of Cash, Cash Equivalents and Trading and Available-for-sale Investments by Balance Sheet Classification) (Details) - USD ($) $ in Thousands	May 31, 2018	Nov. 30, 2017	May 31, 2017	Nov. 30, 2016
Cash, Cash Equivalents and Investments [Line Items]
Cash and Equivalents	$ 97,121	$ 133,464	$ 197,886	$ 207,036
Short-Term Investments	47,079	50,145
State and municipal bond obligations
Cash, Cash Equivalents and Investments [Line Items]
Cash and Equivalents	0	0
Short-Term Investments	32,139	40,227
U.S. treasury bonds
Cash, Cash Equivalents and Investments [Line Items]
Cash and Equivalents	0	0
Short-Term Investments	6,676	3,491
Corporate bonds
Cash, Cash Equivalents and Investments [Line Items]
Cash and Equivalents	0	0
Short-Term Investments	8,264	6,427
Cash
Cash, Cash Equivalents and Investments [Line Items]
Cash and Equivalents	96,523	130,547
Short-Term Investments	0	0
Money market funds
Cash, Cash Equivalents and Investments [Line Items]
Cash and Equivalents	598	2,917
Short-Term Investments	$ 0	$ 0