Reconciliation of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Balance at January 1,	$ 1,982	$ 2,402	$ 3,369
Additions based on tax positions related to the current year	50	50	50
Additions for tax positions of prior years	74	111	195
Reductions for tax positions of prior years	(94)	(524)	(1,212)
Settlements	(753)	(57)
Balance at December 31,	$ 1,259	$ 1,982	$ 2,402