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	Aug. 31, 2016	Nov. 30, 2015	Aug. 31, 2015	Nov. 30, 2014
Cash, Cash Equivalents and Investments [Line Items]
Cash and Equivalents	$ 188,084	$ 212,379	$ 189,113	$ 263,082
Short-Term Investments	44,600	28,900
State and municipal bond obligations [Member]
Cash, Cash Equivalents and Investments [Line Items]
Cash and Equivalents	0	0
Short-Term Investments	34,532	20,417
U.S. treasury bonds [Member]
Cash, Cash Equivalents and Investments [Line Items]
Cash and Equivalents	0	0
Short-Term Investments	6,534	3,094
U.S. government agency bonds [Member]
Cash, Cash Equivalents and Investments [Line Items]
Cash and Equivalents	0	0
Short-Term Investments	522	1,641
Corporate bonds [Member]
Cash, Cash Equivalents and Investments [Line Items]
Cash and Equivalents	0	0
Short-Term Investments	3,012	3,748
Cash [Member]
Cash, Cash Equivalents and Investments [Line Items]
Cash and Equivalents	179,548	186,241
Short-Term Investments	0	0
Money market funds [Member]
Cash, Cash Equivalents and Investments [Line Items]
Cash and Equivalents	8,536	26,138
Short-Term Investments	$ 0	$ 0