v2.4.0.8
Stockholders' Equity - Additional Information (Detail) (USD $)
1 Months Ended 9 Months Ended
May 14, 2012
Sep. 30, 2013
Nov. 10, 2006
Equity [Abstract]      
Stock authorized to be repurchased under share repurchase program     1,000,000
Repurchase of common stock authorized remaining   1,225,750  
Repurchased shares 2,774,250 0  
Aggregate purchase price of repurchased shares $ 66,637,485    
Share repurchased per share price $ 24.02    
Share repurchased, percentage of outstanding stock 11.80%