Total Income Tax Expense Applying U.S. Federal Income Tax Rate (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Components Of Income Tax Expense Benefit [Line Items]
Computed tax expense at statutory federal rates	$ 18,678	$ 19,911	$ 12,328
Increase (decrease) in taxes resulting from:
State taxes, net of federal income tax benefit	1,983	1,947	1,374
Domestic production deduction	(1,142)	(1,661)	(826)
Income tax credits	(724)	(395)	(343)
Other expenses	121	224	622
Total income tax expense (benefit)	$ 18,916	$ 20,026	$ 13,155

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Amount of current and deferred income tax expense (benefit) attributable to income (loss) from continuing domestic operations within the country of domicile of the entity.

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-Publisher FASB

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to deductions. Including, but not limited to, extraterritorial income exclusion deduction, qualified production activity deduction, dividend deduction, deduction for dividend paid to employee stock ownership plan, Medicare prescription drug benefit subsidy deduction, and other deductions.

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Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to tax credits. Including, but not limited to, research credit, foreign tax credit, investment tax credit, and other tax credits.

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