Income Taxes - Statutory Federal Tax Rate of Income from Continuing Operations (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Income tax at statutory rate, Amount	$ (3,237)	$ 747	$ (195)
Add (deduct):, Amount
State income taxes, net of federal tax benefit, Amount	(859)	429	484
Tax rate difference on foreign income taxes, Amount	46	17	(36)
Non-deductible items, Amount	162	126	155
Increase in valuation allowance against certain deferred tax assets, Amount	13,526	3,700	3,000
Unrecognized tax benefits, Amount	(25)		(33)
Income tax reform impact, Amount	10,877
Other, net, Amount	(875)	11	154
Income tax provision	$ 19,615	$ 5,030	$ 3,529
Income tax at statutory rate	34.00%	34.00%	34.00%
Add (deduct):, Rate
State income taxes, net of federal tax benefit, Rate	(39.10%)	19.60%	(84.40%)
Tax rate difference on foreign income taxes, Rate	2.10%	0.80%	6.20%
Non-deductible items, Rate	7.40%	5.70%	(27.10%)
Increase in valuation allowance against certain deferred tax assets, Rate	615.90%	168.50%	(523.80%)
Unrecognized tax benefits, Rate	(1.10%)		5.80%
Income tax reform impact, Rate	495.30%
Other, net, Rate	(39.90%)	0.50%	(27.00%)
Income (loss) from continuing operations	1074.60%	229.10%	(616.30%)