Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Nov. 30, 2011	Nov. 30, 2010	Nov. 30, 2009
Cash flows from operating activities:
Net income	$ 58,761	$ 48,571	$ 32,755
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of property and equipment	8,832	10,859	11,900
Amortization of acquired intangibles and other	26,246	30,558	28,506
Stock-based compensation	25,999	18,121	21,536
Loss on disposal of property and equipment	114
Tax benefit (deficiency) from stock plans	6,165	9,465	(226)
Excess tax benefit from stock plans	(6,238)	(6,046)	(84)
Allowances for accounts receivable	1,963	(1,400)
Deferred income taxes	1,869	4,004	(367)
Changes in operating assets and liabilities, net of effects from acquisitions:
Accounts receivable	8,053	(18,971)	2,281
Other assets	2,709	(3,159)	(352)
Accounts payable and accrued expenses	(24,679)	12,469	(26,795)
Income taxes payable and uncertain tax positions	11,107	(7,347)	3,300
Deferred revenue	5,393	(923)	(9,696)
Net cash flows from operating activities	126,294	96,201	62,758
Cash flows from investing activities:
Purchases of investments	(152,658)	(38,632)	(80,612)
Sales and maturities of investments	84,441	33,318	72,133
Redemptions at par by issuers of auction rate securities - available-for-sale	6,300	1,235	6,940
Redemptions and sales at par of auction rate securities - trading		17,740	260
Purchases of property and equipment	(17,047)	(9,664)	(7,369)
Acquisitions, net of cash acquired	(22,900)	(49,186)
(Increase) decrease in other noncurrent assets	(433)	26	(531)
Net cash flows from investing activities	(102,297)	(45,163)	(9,179)
Cash flows from financing activities:
Issuance of common stock	49,672	93,670	14,752
Withholding tax payments related to net issuance of restricted stock units	(2,706)	(1,858)	(264)
Repurchase of common stock	(200,009)	(29,336)	(5,202)
Excess tax benefit from stock plans	6,238	6,046	84
Payment of long-term debt	(388)	(358)	(330)
Payment of issuance costs for line of credit	(795)
Net cash flows from financing activities	(147,988)	68,164	9,040
Effect of exchange rate changes on cash	(1,473)	(8,516)	16,769
Net (decrease) increase in cash and equivalents	(125,464)	110,686	79,388
Cash and equivalents, beginning of year	286,559	175,873	96,485
Cash and equivalents, end of year	$ 161,095	$ 286,559	$ 175,873