Stockholders' Equity - Additional Information (Detail) (USD $)
3 Months Ended 24 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Dec. 31, 2014
Equity [Abstract]      
Repurchase of available common stock, authorized amount $ 85,000,000.0    
Shares repurchased under stock repurchase program 300,000 0  
Stock repurchased value exclusive of purchase and administrative costs 4,400,000   48,600,000
Average price per share $ 14.21    
Stock repurchase program remaining authorized repurchase amount $ 32,000,000