Reconciliation of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Balance at January 1,	$ 1,553	$ 1,096	$ 1,259
Additions based on tax positions related to the current year	500	500	500
Additions for tax positions of prior years	113	62	47
Reductions for tax positions of prior years	0	0	0
Settlements	(2)	(105)	(710)
Balance at December 31,	$ 2,164	$ 1,553	$ 1,096