Income Taxes - Components of Income Tax Expense (Benefit) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current taxes:
Federal	$ 6	$ (11)	$ 0
State	8	(48)	(127)
Total current income tax benefit (expense)	14	(59)	(127)
Deferred taxes:
Federal	8	1,193	2,057
State	(195)	1,041	(509)
Total deferred income tax benefit (expense)	(187)	2,234	1,548
Total income tax benefit (expense)	$ (173)	$ 2,175	$ 1,421