Income Taxes - Income Tax Expense (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Current income tax expense (benefit)	$ 14,480	$ (1,152)	$ 43,984	$ 955
Deferred income tax expense (benefit)	(950)	16,312	(1,625)	39,198
Income tax expense, as reported	$ 13,530	$ 15,160	$ 42,359	$ 40,153
Effective tax rate	10.80%	11.40%	11.10%	10.70%

Amount of deferred income tax expense (benefit) pertaining to income (loss) from continuing operations.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration