Income Taxes - Income Tax Expense (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Current income tax expense (benefit)	$ 14,999	$ 746
Deferred income tax expense (benefit)	(1,044)	10,411
Income tax expense, as reported	$ 13,955	$ 11,157
Effective tax rate	10.70%	9.50%