Discontinued Operations and Disposition - Summary of Assets and Liabilities of ASW (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Cash and cash equivalents	$ 1,124	$ 2,044
Current assets of discontinued operations	20,238	22,358
Noncurrent assets of discontinued operations	0	11,432
Current liabilities of discontinued operations	9,458	13,124
ASW Steel Inc [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Cash and cash equivalents	1,124	2,044
Receivables	6,928	5,161
Inventories	13,764	14,109
Other assets	1,708	1,044
Property, plant and equipment, net	11,714	0
Estimated charge for impairment	(15,000)	0
Current assets of discontinued operations	20,238	22,358
Property, plant and equipment, net	0	10,847
Other noncurrent assets	0	585
Noncurrent assets of discontinued operations	0	11,432
Total assets of discontinued operations	20,238	33,790
Accounts payable	8,890	12,036
Accrued payrolls and employee benefits	178	440
Other current liabilities	390	648
Current liabilities of discontinued operations	9,458	13,124
Total liabilities of discontinued operations	$ 9,458	$ 13,124