Accumulated Other Comprehensive Loss - Line Items Affected on Consolidated Statements of Operations for Components Reclassified from Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Depreciation and amortization (foreign currency purchase contracts)	$ (4,586)	$ (4,382)	$ (13,954)	$ (13,110)
Costs of products sold (excluding depreciation and amortization) (futures contracts - copper and aluminum)	(76,389)	(84,490)	(256,563)	(256,333)
(Loss) income before income taxes	(818)	1,311	845	3,757
Other income (loss) - net	211	1,959	2,496	3,424
Income tax effect	(636)	(76)	(1,953)	(541)
Net (loss) income attributable to Ampco-Pittsburgh	(1,959)	809	(2,664)	1,908
Amortization of Unrecognized Employee Benefit Costs [Member] | Reclassification Out of Accumulated Other Comprehensive Income (Loss) [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Other income (loss) - net	(177)	(223)	(534)	(670)
Income tax effect	0	(12)		(58)
Net (loss) income attributable to Ampco-Pittsburgh	(177)	(235)	(534)	(728)
Settlements of Cash Flow Hedges [Member] | Reclassification Out of Accumulated Other Comprehensive Income (Loss) [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Depreciation and amortization (foreign currency purchase contracts)	(6)	(6)	(20)	(20)
Costs of products sold (excluding depreciation and amortization) (futures contracts - copper and aluminum)	(7)	146	(267)	(33)
(Loss) income before income taxes	(13)	140	(287)	(53)
Income tax effect		(5)	7	1
Net (loss) income attributable to Ampco-Pittsburgh	$ (13)	$ 135	$ (280)	$ (52)