Investment in Joint Venture - Summarized Income Statement Information of Unconsolidated Joint Venture (Detail) - Joint Venture - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Schedule of Equity Method Investments [Line Items]
Net sales	$ 16,026	$ 18,582	$ 52,140	$ 55,166
Cost of sales	14,442	15,156	45,126	43,316
Income from operations	1,207	3,204	5,872	11,000
Net income	$ 753	$ 2,685	$ 4,257	$ 9,144