Shareholders' Equity (Narrative) (Details) (USD $)	12 Months Ended
	Nov. 30, 2012	Nov. 30, 2011	Nov. 30, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0
Common stock, shares authorized	200,000,000	200,000,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares issued	59,594,961	61,788,629
Common stock, shares outstanding	59,594,961	61,788,629
Vested restricted stock, fair value (in dollars)	$ 13,886,000	$ 9,160,000	$ 6,333,000
Maximum repurchase of common stock from through November 30, 2013 (in dollars)	350,000,000
Common stock repurchased and retired	(4,494,000)	(8,391,000)	(1,496,000)
Common stock repurchased and retired, value (in dollars)	88,384,000	200,009,000	29,337,000
Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of shares to Board of Directors, shares		31,000	24,000
Issuance of shares to Board of Directors, fair value (in dollars)		700,000	500,000
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested restricted stock, shares			7,500
Vested restricted stock, fair value (in dollars)	0	0	131,000
Deferred Stock Unit [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested restricted stock, shares	7,400
Vested restricted stock, fair value (in dollars)	$ 114,000	$ 40,000	$ 0
Deferred stock units, shares outstanding	74,900
Deferred stock unit represents common stock, share	1
Deferred stock units granted in period, shares		21,700