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Stock-Based Compensation - Additional Information (Detail)
$ in Millions
12 Months Ended
Dec. 31, 2015
USD ($)
shares
2007 Plan [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Total unrecognized compensation cost related to restricted stock granted | $ $ 0.8
Cost expected to be recognized over a weighted-average period 1 year 7 months 6 days
2007 Plan [Member] | Minimum [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Restricted stock awards, vest, period 1 year
2007 Plan [Member] | Maximum [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Restricted stock awards, vest, period 5 years
2000 Plan [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Expiration date for stock options 10 years
Class A Common Stock [Member] | 2007 Plan [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Shares authorized | shares 4,000,000