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, 2015	Nov. 30, 2014	May. 31, 2014	Nov. 30, 2013
Cash, Cash Equivalents and Investments [Line Items]
Cash and Equivalents	$ 166,020	$ 263,082	$ 201,971	$ 198,818
Short-Term Investments	33,101	20,186
State and municipal bond obligations [Member]
Cash, Cash Equivalents and Investments [Line Items]
Short-Term Investments	33,101	20,186
Cash [Member]
Cash, Cash Equivalents and Investments [Line Items]
Cash and Equivalents	144,175	195,189
Money market funds [Member]
Cash, Cash Equivalents and Investments [Line Items]
Cash and Equivalents	$ 21,845	$ 67,893