Income Taxes - Provision (Benefit) for Income Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Federal:
Current	$ 122	$ (1)
Deferred	627	(2,962)
Gross Federal	749	(2,963)
State:
Current	80	100
Deferred	17	(6)
Gross State	97	94
Income tax expense (benefit)	$ 846	$ (2,869)