Consolidated Statements Of Shareholders' Equity (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Director [Member]	Director [Member] Common Stock [Member]
Balance, beginning of year at Nov. 30, 2010	$ 690,273	$ 665	$ 346,938	$ 350,409	$ (7,739)
Balance, beginning of year, shares at Nov. 30, 2010		66,528,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock under employee stock purchase plan, shares		594,000
Issuance of stock under the employee stock purchase plan, value	6,844	6	6,838
Exercise of stock options, shares		2,755,000
Exercise of stock options, value	42,828	28	42,800
Issuance of shares to Board of Directors, shares							31,000
Issuance of shares to Board of Directors, value						0	0
Vesting of restricted stock units, shares		386,000
Vesting of restricted stock units, value	4	4
Withholding tax payments related to net issuance of restricted stock units, shares		(114,000)
Withholding tax payments related to net issuance of restricted stock units, value	(2,706)	(1)	(2,705)
Tax benefit arising from employee stock purchase plan, stock options and restricted share activity	6,162	0	6,162
Stock-based compensation	25,999		25,999
Treasury stock repurchases and retirements, shares	(8,391,000)	(8,391,000)
Treasury stock repurchases and retirements, value	(200,009)	(84)	(117,429)	(82,496)
Unrealized gain (loss) on investments, net of tax	354
Net income	59,629			59,629
Other comprehensive income (losses)	(3,914)				(3,914)
Balance, end of year at Nov. 30, 2011	625,110	618	308,603	327,542	(11,653)
Balance, end of year, shares at Nov. 30, 2011		61,789,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock under employee stock purchase plan, shares		376,000
Issuance of stock under the employee stock purchase plan, value	5,654	4	5,650
Exercise of stock options, shares		1,488,000
Exercise of stock options, value	23,435	15	23,420
Issuance of shares to Board of Directors, shares							0
Issuance of shares to Board of Directors, value						0	0
Vesting of restricted stock units, shares		625,000
Vesting of restricted stock units, value	6	6
Withholding tax payments related to net issuance of restricted stock units, shares		(189,000)
Withholding tax payments related to net issuance of restricted stock units, value	(4,155)	(2)	(4,153)
Tax benefit arising from employee stock purchase plan, stock options and restricted share activity	167	0	167
Stock-based compensation	28,233		28,233
Treasury stock repurchases and retirements, shares	(4,494,000)	(4,494,000)
Treasury stock repurchases and retirements, value	(88,384)	(45)	(62,183)	(26,156)
Unrealized gain (loss) on investments, net of tax	1,527
Net income	47,444			47,444
Other comprehensive income (losses)	889				889
Balance, end of year at Nov. 30, 2012	638,399	596	299,737	348,830	(10,764)
Balance, end of year, shares at Nov. 30, 2012	59,594,961	59,595,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock under employee stock purchase plan, shares		281,000
Issuance of stock under the employee stock purchase plan, value	4,298	3	4,295
Exercise of stock options, shares	2,722,000	2,722,000
Exercise of stock options, value	50,466	27	50,439
Vesting of restricted stock units, shares		697,000
Vesting of restricted stock units, value	7	7
Withholding tax payments related to net issuance of restricted stock units, shares		(203,000)
Withholding tax payments related to net issuance of restricted stock units, value	(4,938)	(2)	(4,936)
Tax benefit arising from employee stock purchase plan, stock options and restricted share activity	(520)	0	(520)
Stock-based compensation	21,399		21,399
Treasury stock repurchases and retirements, shares	(11,579,000)	(11,579,000)
Treasury stock repurchases and retirements, value	(269,469)	(116)	(165,622)	(103,731)
Unrealized gain (loss) on investments, net of tax	171
Net income	74,907			74,907
Other comprehensive income (losses)	(895)				(895)
Balance, end of year at Nov. 30, 2013	$ 513,654	$ 515	$ 204,792	$ 320,006	$ (11,659)
Balance, end of year, shares at Nov. 30, 2013	51,512,595	51,513,000