Annual report pursuant to Section 13 and 15(d)

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

v2.4.0.6
Schedule of Stock Activity Related to Share-Based Compensation (Detail)
 12 Months Ended
Dec. 31, 2012
Restricted Stock
  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Awards expected to vest by period 43,687
Restricted Stock | 2013
  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Awards expected to vest by period 24,019
Restricted Stock | 2014
  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Awards expected to vest by period 12,354
Restricted Stock | 2015
  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Awards expected to vest by period 7,314
Restricted Stock Units (RSUs)
  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Awards expected to vest by period 969,820
Restricted Stock Units (RSUs) | 2013
  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Awards expected to vest by period 475,689
Restricted Stock Units (RSUs) | 2014
  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Awards expected to vest by period 494,131