Earnings Per Share (Basic and Diluted Earnings (Loss) Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Aug. 31, 2017	Aug. 31, 2016	Aug. 31, 2017	Aug. 31, 2016
Earnings Per Share [Abstract]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares)	2,500	6,600	2,500	6,600
Numerator:
Net income	$ 50,208	$ 39,363	$ 96,249	$ 68,087
Less: Distributed earnings allocated to nonvested restricted stock	(14)	(10)	(43)	(31)
Less: Undistributed earnings allocated to nonvested restricted stock	(307)	(180)	(602)	(296)
Numerator for basic earnings per share	49,887	39,173	95,604	67,760
Interest expense and amortization of debt issuance costs associated with convertible senior notes, net of taxes	664	667	1,990	2,000
Add: Undistributed earnings allocated to nonvested restricted stock	307	180	602	296
Less: Undistributed earnings reallocated to nonvested restricted stock	(267)	(161)	(528)	(264)
Numerator for diluted earnings per share	$ 50,591	$ 39,859	$ 97,668	$ 69,792
Denominator:
Weighted average shares outstanding — basic (in shares)	85,974	84,457	85,517	85,952
Effect of dilutive securities: Share-based payments (in shares)	4,536	2,344	3,705	2,083
Effect of dilutive securities: Convertible senior notes (in shares)	8,402	8,402	8,402	8,402
Weighted average shares outstanding — diluted (in shares)	98,912	95,203	97,624	96,437
Basic earnings per share (in dollars per share)	$ 0.58	$ 0.46	$ 1.12	$ 0.79
Diluted earnings per share (in dollars per share)	$ 0.51	$ 0.42	$ 1.00	$ 0.72