Quarterly report pursuant to Section 13 or 15(d)

Summary of Compensation Expense under Share-Based Payment Arrangements and Related Tax Benefit (Detail)

v2.4.0.6
Summary of Compensation Expense under Share-Based Payment Arrangements and Related Tax Benefit (Detail) (USD $)
In Thousands, unless otherwise specified
3 Months Ended
Mar. 31, 2013
Mar. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Share-based compensation $ 2,255 $ 2,659
Tax benefit computed at the statutory rate 789 931
Restricted Stock
   
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Share-based compensation 99 106
Restricted Stock Units (RSUs)
   
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Share-based compensation $ 2,156 $ 2,553