Business Segments - Additional Information (Detail) $ in Thousands	3 Months Ended
Mar. 31, 2019 USD ($) Segment	Mar. 31, 2018 USD ($)
Segment Reporting Information [Line Items]
Number of reportable business segments \| Segment	2
Impairment charge	$ 10,082	$ 0
Corporate and Other [Member] \| Other Expense [Member]
Segment Reporting Information [Line Items]
Contractual settlement	2,425
Forged and Cast Engineered Products [Member] \| Operating Loss [Member] \| Akers National Roll Company [Member]
Segment Reporting Information [Line Items]
Impairment charge	$ 10,082

Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=109226348&loc=d3e2420-110228

Name:	us-gaap_AssetImpairmentCharges
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration