XML 18 R42.htm IDEA: XBRL DOCUMENT v3.2.0.727
Treasury Stock - Additional Information (Detail) - USD ($)
shares in Thousands
 6 Months Ended 12 Months Ended
Jun. 30, 2015
Dec. 31, 2014
Stockholders Equity [Line Items]    
Expiration date on repurchase authorizations Sep. 30, 2016  
Common Stock [Member]    
Stockholders Equity [Line Items]    
Common stock acquired, shares 0 2,787
Since Approval of Share Repurchase Plan [Member]    
Stockholders Equity [Line Items]    
Aggregate cost shares of common stock $ 49,135,000  
Remaining authorized repurchase amount 25,865,000  
Maximum [Member]    
Stockholders Equity [Line Items]    
Authorization amount for repurchase of common stock $ 75,000,000