Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Statutory federal income tax rate	21.00%	35.00%	35.00%
Increase in income tax expense		$ 511,000
Valuation allowance	$ 0	$ 0
Liability for uncertain tax positions, current	0
Unrecognized tax benefits	$ 0

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

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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 increase (decrease) in the income tax rates.

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Amount recognized for uncertainty in income taxes classified as current.

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Amount of unrecognized tax benefits.

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