Summary of Activity in Allowance for Doubtful Accounts (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Accounting Policies [Abstract]
Balance at beginning of year	$ 973	$ 1,391
Additions charged to costs	1,005	1,239
Recoveries recognized in costs	(1,006)	(1,708)
Reclassified to assets held for sale	(96)
Adjustment due to currency translation	(25)	51
Balance at end of year	$ 851	$ 973