Income Taxes - Summary of Changes in Valuation Allowance (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Valuation allowance at beginning of year	$ 7,294	$ 7,428	$ 7,743
Current year income			(101)
State net operating loss			(155)
Other changes	(59)	(134)	(59)
Valuation allowance at end of year	$ 7,235	$ 7,294	$ 7,428