Earnings Per Share (Basic and Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Aug. 31, 2018	Aug. 31, 2017	Aug. 31, 2018	Aug. 31, 2017
Numerator:
Net income	$ 87,476	$ 50,208	$ 73,529	$ 96,249
Less: Distributed earnings allocated to nonvested restricted stock	(12)	(14)	(37)	(43)
Less: Undistributed earnings allocated to nonvested restricted stock	(472)	(307)	(388)	(602)
Numerator for basic earnings per share	86,992	49,887	73,104	95,604
Interest expense and amortization of debt issuance costs associated with convertible senior notes, net of taxes	796	664	2,389	1,990
Add: Undistributed earnings allocated to nonvested restricted stock	472	307	388	602
Less: Undistributed earnings reallocated to nonvested restricted stock	(416)	(267)	(335)	(528)
Numerator for diluted earnings per share	$ 87,844	$ 50,591	$ 75,546	$ 97,668
Denominator:
Weighted average shares outstanding — basic (in shares)	87,951	85,974	87,565	85,517
Effect of dilutive securities: Share-based payments (in shares)	4,719	4,536	5,246	3,705
Effect of dilutive securities: Convertible senior notes (in shares)	8,402	8,402	8,402	8,402
Weighted average shares outstanding — diluted (in shares)	101,072	98,912	101,213	97,624
Basic earnings per share (in dollars per share)	$ 0.99	$ 0.58	$ 0.83	$ 1.12
Diluted earnings per share (in dollars per share)	$ 0.87	$ 0.51	$ 0.75	$ 1.00
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares)	1,600	2,500	1,600	2,500