Income Taxes - Income Tax Expense (Benefit), Continuing Operations (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current:
Federal	$ 16,677	$ 22,265	$ 15,782
State	3,829	4,632	2,527
Deferred	2,676	1,951	250
Income tax expense (benefit)	$ 23,182	$ 28,848	$ 18,559