Income Taxes - Income Tax Uncertainties (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]
Beginning balance	$ 788	$ 278	$ 403
Additions for tax positions of prior years	454	625	90
Reductions for tax positions of prior years	(25)	(8)	(11)
Lapse of statute of limitations	(102)	(25)	(24)
Settlements	0	(82)	(180)
Ending balance	$ 1,115	$ 788	$ 278