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, 2016	Nov. 30, 2015	May 31, 2015	Nov. 30, 2014
Cash, Cash Equivalents and Investments [Line Items]
Cash and Equivalents	$ 179,733	$ 212,379	$ 166,020	$ 263,082
Short-Term Investments	49,376	28,900
State and municipal bond obligations [Member]
Cash, Cash Equivalents and Investments [Line Items]
Cash and Equivalents	0	0
Short-Term Investments	39,587	20,417
U.S. treasury bonds [Member]
Cash, Cash Equivalents and Investments [Line Items]
Cash and Equivalents	0	0
Short-Term Investments	4,652	3,094
U.S. government agency bonds [Member]
Cash, Cash Equivalents and Investments [Line Items]
Cash and Equivalents	0	0
Short-Term Investments	1,633	1,641
Corporate bonds [Member]
Cash, Cash Equivalents and Investments [Line Items]
Cash and Equivalents	0	0
Short-Term Investments	3,504	3,748
Cash [Member]
Cash, Cash Equivalents and Investments [Line Items]
Cash and Equivalents	174,198	186,241
Short-Term Investments	0	0
Money market funds [Member]
Cash, Cash Equivalents and Investments [Line Items]
Cash and Equivalents	5,535	26,138
Short-Term Investments	$ 0	$ 0