Income Taxes - Summary of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of period	$ 140	$ 117	$ 65
Increases in positions taken in a current period	0	38	52
Decreases due to settlements	(140)	(15)	0
Balance at end of period	$ 0	$ 140	$ 117