Income Taxes - Components of Comprehensive Provision for Income Taxes Allocation (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Comprehensive provision for income taxes (benefit) allocable to:
Income (loss) from continuing operations	$ 579	$ (15,361)	$ (5,634)
Additional paid-in capital	(200)
Other comprehensive income (loss):
Currency translation	(100)	(2,100)	6,100
Marketable securities			14,300
Interest rate swap			200
Total	(500)	(18,100)	16,800
Defined Benefit Pension Plans
Other comprehensive income (loss):
Defined benefit plans	$ (800)	$ (600)	1,900
OPEB
Other comprehensive income (loss):
Defined benefit plans			$ (100)