Discontinued Operations - Summary of Major Line Items Included in Results of Operations of Discontinued Operations (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Discontinued Operations and Disposal Groups [Abstract]
Net sales		$ 31,600		$ 168,287
Cost of sales (exclusive of depreciation and amortization shown separately below)		26,070		130,555
Selling, general and administrative expense		2,466		11,587
Depreciation and amortization		1,611		7,722
Restructuring and integration expense		0		429
Income from operations		1,453		17,994
Interest income (expense)		7		(181)
Other income (expense)		(66)		(84)
Income from discontinued operations before gain on disposal and provision for income taxes		1,394		17,729
Provision for income taxes		5,362		(219)
Income (loss) from discontinued operations before gain on disposal		6,756		17,510
Gain on disposal of discontinued operations		208,896		208,896
Provision for income taxes on gain on disposal		(86,211)		(86,211)
Income from discontinued operations, net of tax	$ 0	$ 129,441	$ 0	$ 140,195