Discontinued Operations and Disposition - Summary of Major Classes of ASW's Loss from Discontinued Operations, Net of Tax in the Consolidated Statements of Operations (Detail) - ASW Steel Inc [Member] - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Net sales	$ 35,045	$ 63,740
Costs of products sold (excluding depreciation and amortization)	42,407	68,381
Selling and administrative	1,741	2,441
Depreciation and amortization	0	1,311
Loss (gain) on disposal of assets	55	(153)
Charge for impairment	0	15,000
Loss from discontinued operations	(9,158)	(23,240)
Other income (expense)	73	(661)
Loss from discontinued operations before income taxes	(9,085)	(23,901)
Income tax provision	0	0
Loss from discontinued operations, net of tax	$ (9,085)	$ (23,901)