v2.4.1.9
Income Taxes - Summary of Differences Between Provision for Income Taxes and Income Taxes Computed Using Federal Income Tax Rate (Detail) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Income Tax Disclosure [Abstract]      
Amount computed using the statutory rate $ 19,655us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate $ 24,739us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate $ 10,282us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate
State income taxes, net of federal tax benefit 691us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes 1,063us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes 463us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes
Qualified domestic production activity deduction (1,698)us-gaap_IncomeTaxReconciliationDeductionsQualifiedProductionActivities (1,797)us-gaap_IncomeTaxReconciliationDeductionsQualifiedProductionActivities (1,522)us-gaap_IncomeTaxReconciliationDeductionsQualifiedProductionActivities
Other items 386us-gaap_IncomeTaxReconciliationOtherReconcilingItems (232)us-gaap_IncomeTaxReconciliationOtherReconcilingItems 342us-gaap_IncomeTaxReconciliationOtherReconcilingItems
Total Income Tax Expense $ 19,034us-gaap_IncomeTaxExpenseBenefit $ 23,773us-gaap_IncomeTaxExpenseBenefit $ 9,565us-gaap_IncomeTaxExpenseBenefit