Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $)
In Thousands
 6 Months Ended
May 31, 2011
May 31, 2010
Cash flows from operating activities:    
Net income $ 38,481 $ 18,052
Adjustments to reconcile net income to net cash provided by operating activities:    
Depreciation and amortization of property and equipment 4,395 5,738
Amortization of acquired intangible assets 12,161 15,483
Stock-based compensation 9,287 9,003
Deferred income taxes 224 1,151
Tax benefit from stock plans 5,434 4,802
Excess tax benefit from stock plans (4,210) (3,145)
Changes in operating assets and liabilities, net of effects from acquisitions:    
Accounts receivable 32,291 9,381
Other current assets 2,315 (3,761)
Accounts payable and accrued liabilities (23,720) 1,868
Income taxes payable 5,755 (11,939)
Deferred revenue 6,630 4,285
Net cash provided by operating activities 89,043 50,918
Cash flows from investing activities:    
Purchases of investments available for sale (64,525) (13,808)
Sales and maturities of investments available for sale 21,827 21,066
Redemptions at par by issuers of auction rate securities 6,200 8,725
Purchases of property and equipment (8,494) (4,076)
Acquisitions   (49,177)
Decrease (increase) in other non-current assets (888) 236
Net cash used for investing activities (45,880) (37,034)
Cash flows from financing activities:    
Issuance of common stock 35,797 62,996
Withholding tax payments related to net issuance of restricted stock units (1,505)  
Excess tax benefit from stock plans 4,210 3,145
Payment of long-term debt (190) (173)
Repurchase of common stock (64,899) (11,536)
Net cash provided by (used for) financing activities (26,587) 54,432
Effect of exchange rate changes on cash 7,307 (16,461)
Net increase in cash and equivalents 23,883 51,855
Cash and equivalents, beginning of period 286,559 175,873
Cash and equivalents, end of period $ 310,442 $ 227,728