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	Nov. 30, 2017	Nov. 30, 2016	Nov. 30, 2015	Nov. 30, 2014
Cash, Cash Equivalents and Investments [Line Items]
Cash and Equivalents	$ 133,464	$ 207,036	$ 212,379	$ 263,082
Short-Term Investments	50,145	42,718
State and Municipal Bond Obligations [Member]
Cash, Cash Equivalents and Investments [Line Items]
Cash and Equivalents	0	0
Short-Term Investments	40,227	32,724
US Treasury Bonds [Member]
Cash, Cash Equivalents and Investments [Line Items]
Cash and Equivalents	0	0
Short-Term Investments	3,491	6,513
Corporate Bonds [Member]
Cash, Cash Equivalents and Investments [Line Items]
Cash and Equivalents	0	0
Short-Term Investments	6,427	3,481
Cash [Member]
Cash, Cash Equivalents and Investments [Line Items]
Cash and Equivalents	130,547	196,863
Short-Term Investments	0	0
Money Market Funds [Member]
Cash, Cash Equivalents and Investments [Line Items]
Cash and Equivalents	2,917	10,173
Short-Term Investments	$ 0	$ 0