Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Nov. 30, 2011	Nov. 30, 2010	Nov. 30, 2009
Operating activities:
Net income	$ 112,635	$ 78,471	$ 62,520
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation of property and equipment	13,145	13,414	15,107
Amortization of acquired intangible assets	34,661	32,494	27,628
Stock-based compensation	48,867	32,248	23,546
Deferred income tax	1,266	(8,478)	(12,630)
Tax benefits related to employee stock option plans	8,552	30,626	21,573
Excess tax benefits from stock-based compensation	(41,950)	(21,510)	(17,016)
Other non-cash adjustments, net	476	225	1,207
Changes in assets and liabilities, net of effects of acquisitions:
Accounts receivable	(3,312)	(25,909)	(20,896)
Prepaid expenses and other assets	5,631	14,518	7,465
Accounts payable	501	3,829	2,300
Accrued liabilities and restructuring costs	7,015	(12,553)	(7,735)
Deferred revenue	20,563	11,382	12,328
Net cash provided by operating activities	208,050	148,757	115,397
Investing activities:
Purchases of short-term investments	(76)	(1,313)
Maturities and sales of short-term investments	1,451	183	12,448
Acquisitions, net of cash acquired	(63,610)	(78,573)	(27,340)
Proceeds from sales of private equity investments		485	117
Purchases of property and equipment	(13,971)	(6,399)	(5,388)
Restricted cash pledged as security	(3,234)	(5,498)	(2,571)
Net cash used in investing activities	(79,440)	(91,115)	(22,734)
Financing activities:
Proceeds from issuance of common stock	80,610	86,940	28,403
Proceeds from revolving credit facility	30,000
Repurchases of the Company's common stock	(194,059)	(204,280)	(106,447)
Withholding taxes related to restricted stock net share settlement	(17,922)	(6,140)	(2,283)
Excess tax benefits from stock-based compensation	41,950	21,510	17,016
Principal payments on long-term debt	(2,269)	(3,492)	(2,033)
Payment of issuance costs for revolving credit facility			(2,317)
Net cash used in financing activities	(61,690)	(105,462)	(67,661)
Effect of foreign exchange rate changes on cash and cash equivalents	(2,761)	(720)	13,127
Net increase (decrease) in cash and cash equivalents	64,159	(48,540)	38,129
Cash and cash equivalents at beginning of year	243,989	292,529	254,400
Cash and cash equivalents at end of year	308,148	243,989	292,529
Supplemental disclosures:
Interest paid	2,994	3,023	2,400
Income taxes paid	$ 12,883	$ 22,770	$ 18,573