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, 2022	Mar. 31, 2021
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Depreciation and amortization (foreign currency purchase contracts)	$ (4,487)	$ (4,743)
Costs of products sold (excluding depreciation and amortization)(futures contracts – copper and aluminum)	(78,820)	(69,588)
Income before income taxes	1,665	695
Other income – net	1,412	665
Income tax provision	(56)	(381)
Net income attributable to Ampco-Pittsburgh	1,645	167
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 – net	368	376
Income tax provision	(3)	(14)
Net income attributable to Ampco-Pittsburgh	365	362
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)	(7)	(7)
Costs of products sold (excluding depreciation and amortization)(futures contracts – copper and aluminum)	(91)	(324)
Income before income taxes	(98)	(331)
Income tax provision	3	0
Net income attributable to Ampco-Pittsburgh	$ (95)	$ (331)