Revenue from Contracts with Customers - Condensed Consolidated Statement of Operations (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Other current assets	$ 24,494		$ 24,494		$ 18,518
Net sales	196,349	$ 157,947	365,497	$ 315,502
Cost of sales	148,640	114,514	275,084	228,994
Income from operations	(292)	$ 12,642	3,401	$ 26,494
Balances Without Adoption of ASC 606 [Member] | Accounting Standards Update 2014-09 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	196,367		365,569
Cost of sales	148,631		275,120
Income from operations	(265)		3,437
Effect of Change [Member] | Accounting Standards Update 2014-09 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	(18)		(72)
Cost of sales	9		(36)
Income from operations	$ (27)		$ (36)