Annual report pursuant to Section 13 and 15(d)

Stockholder's Equity - Additional Information (Detail)

v2.4.0.6
Stockholder's Equity - Additional Information (Detail) (USD $)
 1 Months Ended 12 Months Ended
Dec. 28, 2012
Nov. 29, 2012
Sep. 28, 2012
Aug. 30, 2012
Jun. 29, 2012
May 31, 2012
Mar. 31, 2012
Mar. 07, 2012
Dec. 13, 2010
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Compensation Related Costs Share Based Payments Disclosure [Line Items]                        
Class A and Class B common stock, dividend declared per share   $ 0.035   $ 0.035   $ 0.035 $ 0.035 $ 0.035        
Class A and Class B common stock, dividend declared date             Mar. 07, 2012          
Class A and Class B common stock, dividend paid                   $ 3,400,000    
Class A and Class B common stock, dividend paid per share $ 0.035   $ 0.035   $ 0.035   $ 0.035          
Class A and Class B common stock, expected annual dividend payment                   3,400,000    
Total cash distribution                 4,800,000      
Stock based compensation expenses                   $ 1,368,000 $ 950,000 $ 1,437,000
Common Class A
                        
Compensation Related Costs Share Based Payments Disclosure [Line Items]                        
Special cash distribution                 $ 0.20      
Common Class B
                        
Compensation Related Costs Share Based Payments Disclosure [Line Items]                        
Special cash distribution                 $ 0.20