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		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Depreciation and amortization (foreign currency purchase contracts)	$ (4,698)	$ (4,354)	$ (9,368)	$ (8,728)
Costs of products sold (excluding depreciation and amortization) (futures contracts - copper and aluminum)	(87,684)	(85,471)	(180,174)	(171,843)
Income before income taxes	3,415	1,148	1,663	2,446
Other income (loss) - net	1,381	98	2,285	1,465
Income tax effect	(863)	(152)	(1,317)	(465)
Net income (loss) attributable to Ampco-Pittsburgh	2,012	423	(705)	1,099
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	(174)	(265)	(357)	(447)
Income tax effect	0	(33)		(46)
Net income (loss) attributable to Ampco-Pittsburgh	(174)	(298)	(357)	(493)
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)	(8)	(8)	(14)	(14)
Costs of products sold (excluding depreciation and amortization) (futures contracts - copper and aluminum)	(278)	(68)	(260)	(179)
Income before income taxes	(286)	(76)	(274)	(193)
Income tax effect	8	3	7	6
Net income (loss) attributable to Ampco-Pittsburgh	$ (278)	$ (73)	$ (267)	$ (187)