Acquisition - Summary of Pro Forma Financial Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Net loss attributable to Ampco-Pittsburgh	$ (85,778)	$ (24,740)
Net loss per common share (basic) attributable to Ampco-Pittsburgh	$ (6.94)	$ (2.03)
Akers AB [Member]
Business Acquisition [Line Items]
Net sales	$ 393,243	$ 440,265
Loss before income taxes (includes noncontrolling interest)	$ (63,498)	$ (11,945)

Business Acquisitions Pro Forma Income Loss Before Tax

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

The pro forma basic net income per share for a period as if the business combination or combinations had been completed at the beginning of a period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(2)-(3)
-URI http://asc.fasb.org/extlink&oid=65885119&loc=d3e1392-128463

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- Definition

The pro forma net Income or Loss for the period as if the business combination or combinations had been completed at the beginning of a period.

+ References

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- Definition

The pro forma revenue for a period as if the business combination or combinations had been completed at the beginning of the period.

+ References

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