Contractual settlement.

No definition available.

Name:	ap_ContractualSettlement
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Curtailment gain.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- Definition

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.

+ References

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=118932676&loc=d3e3602-108585

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

+ Details

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Balance Type:	debit
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- Definition

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Dividends received on equity and other investments during the current period.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 16
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3337-108585

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of expense (reversal of expense) for expected credit loss on accounts receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=119407570&loc=SL82919249-210447

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
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-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(5))
-URI http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- 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.

+ Details

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- Details

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Balance Type:
Period Type:

- Details

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Balance Type:
Period Type:

- Details

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Balance Type:
Period Type:

- Details

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Namespace Prefix:
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Balance Type:
Period Type:

- Details

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Business Segments - Additional Information (Detail) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($) Segment	Sep. 30, 2018 USD ($)
Segment Reporting Information [Line Items]
Number of reportable business segments \| Segment				2
Impairment charge	$ 0		$ 0	$ 10,082	$ 0
Akers National Roll Company [Member]
Segment Reporting Information [Line Items]
Impairment charge		$ 10,082
Corporate and Other [Member] \| Other Expense [Member]
Segment Reporting Information [Line Items]
Contractual settlement				2,425
Dividends received			$ 400	1,400
Corporate and Other [Member] \| Other Expense [Member] \| Akers National Roll Company [Member]
Segment Reporting Information [Line Items]
Curtailment Gain	$ 2,304			2,304
Forged and Cast Engineered Products [Member]
Segment Reporting Information [Line Items]
Provision for doubtful accounts				1,366
Forged and Cast Engineered Products [Member] \| Operating Loss [Member] \| Akers National Roll Company [Member]
Segment Reporting Information [Line Items]
Impairment charge				$ 10,082