Annual report pursuant to Section 13 and 15(d)

Share-based Compensation - Share-Based Compensation Expense and Related Tax Benefits (Detail)

v2.4.1.9
Share-based Compensation - Share-Based Compensation Expense and Related Tax Benefits (Detail) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]      
Share-based compensation expense $ 2,165us-gaap_ShareBasedCompensation $ 705us-gaap_ShareBasedCompensation $ 478us-gaap_ShareBasedCompensation
Related tax benefits $ 516us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense $ 32us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense $ 201us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense