Earnings (Loss) Per Share (Details) (USD $)	3 Months Ended		9 Months Ended			0 Months Ended
	Aug. 31, 2014	Aug. 31, 2013	Aug. 31, 2014	Aug. 31, 2013	Jan. 29, 2013 Convertible Senior Notes Due Two Thousand Nineteen At One Point Three Seven Five Percent [Member] [Member]	Jan. 29, 2013 Convertible Notes Payable [Member] Convertible Senior Notes Due Two Thousand Nineteen At One Point Three Seven Five Percent [Member] [Member]	Aug. 31, 2014 Convertible Notes Payable [Member] Convertible Senior Notes Due Two Thousand Nineteen At One Point Three Seven Five Percent [Member] [Member]	Nov. 30, 2013 Convertible Notes Payable [Member] Convertible Senior Notes Due Two Thousand Nineteen At One Point Three Seven Five Percent [Member] [Member]	Jan. 29, 2013 Convertible Notes Payable [Member] Convertible Senior Notes Due Two Thousand Nineteen At One Point Three Seven Five Percent [Member]
Debt Instrument [Line Items]
Net Income (Loss) Attributable to Parent	$ 28,361,000	$ 27,278,000	$ 65,548,000	$ 11,847,000
Debt Instrument, Face Amount						230,000,000
Debt Instrument, Interest Rate, Stated Percentage					1.375%		1.375%	1.375%	1.375%
Debt Conversion, Converted Instrument, Shares Issued						36.5297
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	5,200,000	5,200,000	5,200,000	5,200,000
Less: Distributed earnings allocated to nonvested restricted stock	(6,000)	(6,000)	(18,000)	(18,000)
Undistributed Earnings Allocated to Participating Securities	(73,000)	(73,000)	(159,000)	(16,000)
Numerator for basic earnings per share	28,282,000	27,199,000	65,371,000	11,813,000
Interest expense and amortization of debt issuance costs associated with convertible senior notes, net of taxes	667,000	667,000	2,000,000	0
Less: Undistributed earnings reallocated to nonvested restricted stock	(66,000)	(65,000)	(142,000)	(14,000)
Numerator for diluted earnings per share	$ 28,956,000	$ 27,874,000	$ 67,388,000	$ 11,815,000
Weighted Average Number of Shares Outstanding, Basic	91,793,000	83,714,000	88,389,000	82,261,000
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	1,875,000	1,931,000	1,823,000	2,028,000
Incremental Common Shares Attributable to Dilutive Effect of Conversion of Debt Securities	8,402,000	8,402,000	8,402,000	0		8,401,831
Weighted Average Number of Shares Outstanding, Diluted	102,070,000	94,047,000	98,614,000	84,289,000
Earnings Per Share, Basic, in dollars per share	$ 0.31	$ 0.32	$ 0.74	$ 0.14
Earnings Per Share, Diluted, in dollars per share	$ 0.28	$ 0.30	$ 0.68	$ 0.14