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
	Mar. 31, 2025	Mar. 31, 2024
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Depreciation and amortization (foreign currency purchase contracts)	$ (4,636)	$ (4,670)
Costs of products sold (excluding depreciation and amortization) (futures contracts - copper and aluminum)	(82,104)	(92,490)
Income (loss) before income taxes	1,950	(1,752)
Other income (loss) - net	826	923
Income tax effect	(59)	(454)
Net income (loss) attributable to Ampco-Pittsburgh	1,142	(2,717)
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	(65)	(183)
Income tax effect	0	0
Net income (loss) attributable to Ampco-Pittsburgh	(65)	(183)
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)
Costs of products sold (excluding depreciation and amortization) (futures contracts - copper and aluminum)	(55)	18
Income (loss) before income taxes	(61)	12
Income tax effect	2	(1)
Net income (loss) attributable to Ampco-Pittsburgh	$ (59)	$ 11