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Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax [Line Items]
Valuation allowance	$ 0	$ 0
Corporate federal tax rate	21.00%	35.00%	35.00%
Income tax benefit related to revaluation of net deferred tax liabilities	$ 10,700
Effective Income Tax Rate Reconciliation, Percent, Total	20.20%	28.30%	37.10%
Tax Cuts and Jobs Act [Member]
Income Tax [Line Items]
Effective Income Tax Rate Reconciliation, Percent, Total		32.10%

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Income tax.

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Tax Cuts and Jobs Act of 2017, change in tax rate, income tax expense (benefit).

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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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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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