Income Taxes (Income Tax Expense) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Current income tax expense	$ 48,748	$ 59,530	$ 62,177
Deferred income tax expense (benefit)	(11,598)	(19,059)	(4,130)
Income tax expense, as reported	$ 37,150	$ 40,471	$ 58,047