Accumulated Other Comprehensive Loss - Net Change and Ending Balances for Various Components of Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$ 83,658	$ 91,608	$ 91,806	$ 84,999
Net change	(7,457)	(2,079)	(18,214)	(900)
Ending Balance	78,019	88,661	78,019	88,661
Foreign Currency Translation [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			(14,322)	(11,371)
Net change			(19,787)	(2,041)
Ending Balance	(34,109)	(13,412)	(34,109)	(13,412)
Unrecognized Employee Benefit Costs [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			(40,563)	(57,652)
Net change			2,274	1,618
Ending Balance	(38,289)	(56,034)	(38,289)	(56,034)
Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			277	589
Net change			(701)	(477)
Ending Balance	(424)	112	(424)	112
Less: Noncontrolling Interest [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			498	261
Net change			(996)	103
Ending Balance	(498)	364	(498)	364
Accumulated Other Comprehensive Loss Attributable to Ampco-Pittsburgh [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			(55,106)	(68,695)
Net change			(17,218)	(1,003)
Ending Balance	(72,324)	(69,698)	(72,324)	(69,698)
Total Accumulated Other Comprehensive Loss [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			(54,608)	(68,434)
Net change			(18,214)	(900)
Ending Balance	$ (72,822)	$ (69,334)	$ (72,822)	$ (69,334)