Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income tax provision	$ 1,335	$ 1,486	$ 35,801	$ 30,742
Liability for income taxes associated with uncertain tax positions	9,746		9,746
Net amount of unrecognized tax benefit related to uncertain tax positions that would impact, if recognized, effective income tax rate	1,445		1,445
Unrecognized tax benefit liabilities decrease	105		105
Increase in gross liability for uncertain tax positions	237		446
Provision expense (benefit) for income taxes related to interest and penalties	52	$ 132	46	$ 241
Income tax accrued for payment of interest and penalties	$ 1,664		$ 1,664		$ 1,618

Amount of decrease reasonably possible in the next twelve months for the unrecognized tax benefit.

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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 unrecognized tax benefits.

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Amount accrued for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return.

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Amount of expense for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return.

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