Earnings Per Share (Basic and Diluted Loss Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Nov. 30, 2019	Aug. 31, 2019	May 31, 2019	Feb. 28, 2019	Nov. 30, 2018	Aug. 31, 2018	May 31, 2018	Feb. 28, 2018	Nov. 30, 2019	Nov. 30, 2018	Nov. 30, 2017
Numerator:
Net income	$ 123,167	$ 68,136	$ 47,461	$ 30,011	$ 96,836	$ 87,476	$ 57,308	$ (71,255)	$ 268,775	$ 170,365	$ 180,595
Participating Securities, Distributed and Undistributed Earnings (Loss), Basic									(123)	(51)	(56)
Undistributed Earnings (Loss) Allocated to Participating Securities, Basic									(1,505)	(927)	(1,121)
Numerator for basic earnings per share									267,147	169,387	179,418
Interest expense and amortization of debt issuance costs associated with convertible senior notes, net of taxes									541	3,190	2,654
Undistributed Earnings (Loss) Allocated to Participating Securities, Diluted									1,505	927	1,121
Less: Undistributed earnings reallocated to nonvested restricted stock									(1,412)	(805)	(979)
Numerator for diluted earnings per share									$ 267,781	$ 172,699	$ 182,214
Denominator:
Weighted average shares outstanding — basic									87,996	87,773	85,842
Share-based payments, shares									4,415	4,884	4,072
Convertible senior notes, shares									1,427	8,402	8,402
Weighted average shares outstanding — diluted									93,838	101,059	98,316
Basic earnings (loss) per share, in dollars per share	$ 1.37	$ 0.77	$ 0.54	$ 0.34	$ 1.09	$ 0.99	$ 0.65	$ (0.82)	$ 3.04	$ 1.93	$ 2.09
Diluted earnings (loss) per share, in dollars per share	$ 1.31	$ 0.73	$ 0.51	$ 0.31	$ 0.96	$ 0.87	$ 0.57	$ (0.82)	$ 2.85	$ 1.71	$ 1.85