Stockholders' Equity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended												12 Months Ended
	Nov. 30, 2015	Aug. 31, 2015	May. 31, 2015	Feb. 28, 2015	Nov. 30, 2014	Aug. 31, 2014	May. 31, 2014	Feb. 28, 2014	Nov. 30, 2013	Aug. 31, 2013	May. 31, 2013	Feb. 28, 2013	Nov. 30, 2015	Nov. 30, 2014	Nov. 30, 2013	Jul. 17, 2014	Mar. 25, 2014	Jul. 18, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common Stock, Shares Authorized	290,000,000				290,000,000								290,000,000	290,000,000
Common Stock, Capital Shares Reserved for Future Issuance	12,602,735				12,602,735								12,602,735	12,602,735
Authorized repurchase of common stock	4,000,000												4,000,000
Common Stock, Shares, Issued	115,547,682				115,386,512								115,547,682	115,386,512
Treasury Stock, Value	$ 447,043				$ 446,476								$ 447,043	$ 446,476
Stockholder's Equity (Textual) [Abstract]
Number of shares that can be purchased by exercising each right	0.01												0.01
Purchase price for right holders	$ 85.00												$ 85.00
Exercisable options available													earlier of (a) 10 calendar days after a public announcement by us that a person or group has become an Acquiring Person (as defined under the 2009 Rights Agreement) and (b) 10 business days after the commencement of a tender or exchange offer by a person or group if upon consummation of the offer the person or group would beneficially own 4.9% or more of our outstanding common stock.
Calendar days after a public announcement during which rights to be exercised													10 days
Business days after the commencement of a tender or exchange offer during which rights to be exercised													10 days
Beneficially ownership in company's outstanding common stock to be held by person or group to exercise rights													4.90%
Price at which company may redeem all of the then outstanding rights	0.001												$ 0.001
Stock Issued During Period, Shares, New Issues														7,986,111	6,325,000
Common stock, par value, in dollars	1.00				$ 1.00				$ 1.00				$ 1.00	$ 1.00	$ 1.00		$ 1.00
Treasury Stock Acquired, Average Cost Per Share														$ 18.00	$ 18.25
Options under which right issued pursuant to the 2009 rights Agreement will expire													earliest of (a) the close of business on March 5, 2019, (b) the time at which the rights are redeemed, (c) the time at which the rights are exchanged, (d) the time at which our board of directors determines that a related provision in our Restated Certificate of Incorporation is no longer necessary, and (e) the close of business on the first day of a taxable year of ours to which our board of directors determines that no tax benefits may be carried forward. At our annual meeting of stockholders on April 2, 2009, our stockholders approved the 2009 Rights Agreement.
Cash dividend declared per share	$ 0.025	$ 0.025	$ 0.025	$ 0.025	$ 0.025	$ 0.025	$ 0.025	$ 0.025	$ 0.025	$ 0.025	$ 0.025	$ 0.0625
Stock repurchases													$ (567)	$ (546)	$ (8,488)
Proceeds from issuance of common stock, net													$ 0	$ 137,045	$ 109,503
Director Stock Units [Domain]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number																		481,554
Authorized repurchase of common stock																		482,000
Common Stock, Shares, Issued																		478,294
Treasury Stock, Value																		$ 7,900
Director Plan SARs [Domain]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common Stock, Shares Authorized																680,000
Common Stock, Capital Shares Reserved for Future Issuance																679,815
Authorized repurchase of common stock																680,000
Common Stock, Shares, Issued	0												0