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Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)
12 Months Ended
Dec. 31, 2012
Y
Dec. 31, 2011
Dec. 31, 2010
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]      
Term of license, Minimum 1    
Term of license, Maximum 5    
Software development cost amortization period 3    
Investment classified as trading securities $ 0 $ 0  
Percent of corporate wholly-owned subsidiaries 20.00%    
Ownership interest of equity investments in non-public companies Less than 20%    
Restricted stock service vesting period 4 years    
Research and development costs 18,386,000 15,393,000 14,870,000
Advertisement costs 7,455,000 7,065,000 6,877,000
Impairment of goodwill $ 0    
Minimum [Member]
     
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]      
Estimated useful life 3 years    
Maximum [Member]
     
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]      
Estimated useful life 4 years