Income Taxes - Schedule of Income Tax Expense (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Current provision:
Federal	$ 38,957us-gaap_CurrentFederalTaxExpenseBenefit	$ 38,881us-gaap_CurrentFederalTaxExpenseBenefit	$ 35,089us-gaap_CurrentFederalTaxExpenseBenefit
State	15,968	13,996	15,910
Current provision, total	54,925us-gaap_CurrentIncomeTaxExpenseBenefit	52,877us-gaap_CurrentIncomeTaxExpenseBenefit	50,999us-gaap_CurrentIncomeTaxExpenseBenefit
Deferred provision (benefit):
Federal	2,534	(3,260)	(10,102)
State	1,317	(950)	(3,484)
Deferred provision (benefit), total	3,851us-gaap_DeferredIncomeTaxExpenseBenefit	(4,210)us-gaap_DeferredIncomeTaxExpenseBenefit	(13,586)us-gaap_DeferredIncomeTaxExpenseBenefit
Provision for income taxes	$ 58,776us-gaap_IncomeTaxExpenseBenefit	$ 48,667us-gaap_IncomeTaxExpenseBenefit	$ 37,413us-gaap_IncomeTaxExpenseBenefit

Amount of current federal tax expense (benefit) pertaining to income (loss) from continuing operations.

Amount of current income tax expense (benefit) pertaining to taxable income (loss) from continuing operations.

Amount of current state and local tax expense (benefit) pertaining to income (loss) from continuing operations.

Amount of deferred federal income tax expense (benefit) pertaining to income (loss) from continuing operations.

Amount of deferred income tax expense (benefit) pertaining to income (loss) from continuing operations.

Amount of deferred state and local tax expense (benefit) pertaining to income (loss) from continuing operations.