Consolidated Statements Of Shareholders' Equity (USD $) In Thousands, unless otherwise specified	Common Stock And Additional Paid-In Capital [Member]	Retained Earnings And Accumulated Other Comprehensive Income [Member]	Total
Balance, beginning of year at Nov. 30, 2008	$ 216,261	$ 265,191
Exercise of employee stock options	9,054
Issuance of stock under the employee stock purchase plan	5,740
Repurchase and retirement of common stock	(4,794)	(408)	(5,200)
Present value of payments for re-pricing of stock options	(42)
Stock-based compensation	21,536
Withholding tax payments related to net issuance of restricted stock units	(264)
Tax benefit (deficiency) from stock plans	(226)
Net income		32,755	32,755
Other comprehensive income:
Unrealized gains (losses) on investments		319
Translation adjustments		10,330
Comprehensive income		43,404
Balance, end of year at Nov. 30, 2009	247,265	308,187	555,452
Exercise of employee stock options	87,461
Issuance of stock under the employee stock purchase plan	6,209
Repurchase and retirement of common stock	(19,059)	(10,277)	(29,300)
Stock-based compensation	18,121
Withholding tax payments related to net issuance of restricted stock units	(1,858)
Tax benefit (deficiency) from stock plans	9,465
Net income		48,571	48,571
Other comprehensive income:
Unrealized gains (losses) on investments		(207)
Translation adjustments		(5,546)
Comprehensive income		42,818
Balance, end of year at Nov. 30, 2010	347,604	340,728	688,332
Exercise of employee stock options	42,828
Issuance of stock under the employee stock purchase plan	6,844
Repurchase and retirement of common stock	(117,513)	(82,496)	(200,000)
Stock-based compensation	25,999
Withholding tax payments related to net issuance of restricted stock units	(2,706)
Tax benefit (deficiency) from stock plans	6,165
Net income		58,761	58,761
Other comprehensive income:
Unrealized gains (losses) on investments		354
Translation adjustments		(4,268)
Comprehensive income		54,847
Balance, end of year at Nov. 30, 2011	$ 309,221	$ 313,079	$ 622,300