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Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Effective tax rate	36.00%	37.30%	37.70%	37.30%
Tax benefit recognized from tax deduction related to dividends paid on unvested restricted stock grants					$ 1,900,000
Valuation allowance	0		0		0
Interest Expense Recognized from Income tax examination			$ 294,000

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- Definition

Tax benefit recognized from tax deduction related to dividends paid on unvested restricted stock grants.

+ References

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Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

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

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The amount of estimated interest recognized in the period arising from income tax examinations.

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