| Reconciliation of Income Taxes Computed to Income Tax Expense (Detail) (USD $) In Thousands, unless otherwise specified | 12 Months Ended | ||
|---|---|---|---|
| Dec. 31, 2013 | Dec. 31, 2012 | Dec. 31, 2011 | |
| Effective Income Tax Rate Reconciliation, Other Reconciling Items, Amount [Abstract] | |||
| Income tax expense at the federal statutory rate | $ 28,033 | $ 41,836 | $ 92,517 | 
| Qualified domestic production activities | (4,256) | 1,823 | |
| State income taxes | 343 | 750 | 603 | 
| Other | 398 | 705 | 220 | 
| Income tax expense (benefit) | $ 28,774 | $ 47,547 | $ 91,517 | 
| Income tax expense at the federal statutory rate, tax rate | 35.00% | 35.00% | 35.00% | 
| Qualified domestic production activities, tax rate | 3.50% | (0.70%) | |
| State income taxes, tax rate | 0.40% | 0.70% | 0.20% | 
| Other, tax rate | 0.50% | 0.60% | 0.10% | 
| Effective income tax rate, total | 35.90% | 39.80% | 34.60% | 
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- Definition Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Percentage of domestic federal statutory tax rate applicable to pretax income (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Percentage 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 deduction for qualified production activity. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Percentage 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 other adjustments. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Percentage 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 applicable to state and local income tax expense (benefit), net of federal tax expense (benefit). Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Amount of the difference between reported income tax expense (benefit) and the expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to deduction for qualified production activity. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition The amount of income tax expense or benefit for the period computed by applying the domestic federal statutory tax rates to pretax income from continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 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 other adjustments. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Details 
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- Definition 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 state and local income tax expense (benefit). Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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