Earnings Per Share (Basic and Diluted Earnings (Loss) Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	May. 31, 2015	May. 31, 2014	May. 31, 2015	May. 31, 2014
Earnings Per Share [Abstract]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	6,900	5,200	6,900	5,200
Numerator:
Net income	$ 9,573	$ 26,624	$ 17,372	$ 37,187
Less: Distributed earnings allocated to nonvested restricted stock	(8)	(6)	(16)	(12)
Less: Undistributed earnings allocated to nonvested restricted stock	(24)	(66)	(45)	(88)
Numerator for basic earnings per share	9,541	26,552	17,311	37,087
Interest expense and amortization of debt issuance costs associated with convertible senior notes, net of taxes	667	667	1,333	1,333
Add: Undistributed earnings allocated to nonvested restricted stock	24	66	45	88
Less: Undistributed earnings reallocated to nonvested restricted stock	(22)	(59)	(41)	(80)
Numerator for diluted earnings per share	$ 10,210	$ 27,226	$ 18,648	$ 38,428
Denominator:
Weighted average shares outstanding — basic	91,995	89,529	91,974	86,668
Effect of dilutive securities: Share-based payments	1,147	1,577	1,094	1,689
Effect of dilutive securities: Convertible senior notes	8,402	8,402	8,402	8,402
Weighted average shares outstanding — diluted	101,544	99,508	101,470	96,759
Basic earnings per share, in dollars per share	$ 0.10	$ 0.30	$ 0.19	$ 0.43
Diluted earnings per share, in dollars per share	$ 0.10	$ 0.27	$ 0.18	$ 0.40