Quarterly report pursuant to Section 13 or 15(d)

Schedule of Stock Activity Related to Share-Based Compensation (Parenthetical) (Detail)

v2.4.0.8
Schedule of Stock Activity Related to Share-Based Compensation (Parenthetical) (Detail) (Restricted Stock Units (RSUs))
6 Months Ended
Jun. 30, 2013
Minimum | 2014 | Related to TSR Performance Measurements
 
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]  
Restricted Stock Units adjustments, percentage 0.00%
Minimum | 2015 | Related to TSR Performance Measurements
 
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]  
Restricted Stock Units adjustments, percentage 0.00%
Minimum | 2015 | Related to Company Performance Measurements
 
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]  
Restricted Stock Units adjustments, percentage 0.00%
Maximum | 2014 | Related to TSR Performance Measurements
 
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]  
Restricted Stock Units adjustments, percentage 150.00%
Maximum | 2015 | Related to TSR Performance Measurements
 
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]  
Restricted Stock Units adjustments, percentage 200.00%
Maximum | 2015 | Related to Company Performance Measurements
 
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]  
Restricted Stock Units adjustments, percentage 150.00%