Pension and Other Postretirement Benefits - Additional Information (Detail) £ in Thousands	12 Months Ended
	Dec. 31, 2024 USD ($) Customer Employee Pension_Plan Employer	Dec. 31, 2023 USD ($)	Dec. 31, 2024 GBP (£) Pension_Plan	Dec. 31, 2023 GBP (£)	Dec. 31, 2022 USD ($)
Defined Benefit Plans And Other Postretirement Benefit Plans [Line Items]
Decrease in plan's benefit obligation	$ 4,857,000
Actuarial gain impact from lump-sum window	$ 977,000
Number of employers contributed to the plan | Employer	977
Multiemployer plan number of employer locations description	Approximately 977
Number of employees participate in the plan | Employee	0
Multiemployer plan number of employees description	Approximately 100,000
Total amount of assets collected	$ 14,700,000,000
Multiemployer plan pension significant plan asset description	approximately $14.7 billion
Percentage of funded status in excess	86.50%
Multiemployer plans funded status description	approximately 86.5%
Participation of corporation's employees in the plan	Less than 100
Participation of number of corporation's employees in the plan | Employee	100
Percentage of employers contributions	5.00%
Service period to avail existing pension plan	10 years
Number of basis points decrease on benefit plan discount rate		0.32%
Number of basis points increase on benefit plan discount rate	0.55%
Number of basis points decrease in discount rate on projected and accumulated benefit obligations	0.25%
Number of basis points increase in discount rate on projected and accumulated benefit obligations	0.25%
Increase in projected and accumulated benefit obligations due to 25 basis point decrease in discount rate	$ 5,000,000
Decrease in projected and accumulated benefit obligations due to 25 basis point increase in discount rate	5,000,000
Total lump sum payments	$ 3,880,000
Maximum maturity period of fixed income investments	10 years
Percentage point decrease in the expected long-term rate of return would increase annual pension expense	$ 2,300,000
Percentage point increase in the expected long-term rate of return would decrease annual pension expense	$ 2,300,000
Assumed health care cost trend rate for 2023	7.30%		7.30%
Various Equity Funds [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans [Line Items]
Target allocation	Each fund maintains a diversified holding in common stock of applicable companies (e.g., common stock of small capitalization companies if a small-cap fund, common stock of medium capitalization companies if a mid-cap fund, common stock of foreign corporations if an international fund, etc.).
Various Equity Funds [Member] | Primary Investment Objective [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans [Line Items]
Target allocation	Outperform the fund’s related index.
Various Fixed- Income Funds [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans [Line Items]
Target allocation	Invests primarily in a diversified portfolio of fixed-income securities of varying maturities or in commingled funds which invest in a diversified portfolio of fixed-income securities of varying maturities.
Various Fixed- Income Funds [Member] | Primary Investment Objective [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans [Line Items]
Target allocation	Achieve a rate of return that matches or exceeds the expected growth in plan liabilities.
Alternative Investments - Managed Funds [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans [Line Items]
Target allocation	Invests in equities and equity-like asset classes and strategies (such as public equities, venture capital, private equity, real estate, natural resources, and hedged strategies) and fixed-income securities approved by the Retirement Committee.
Alternative Investments - Managed Funds [Member] | Primary Investment Objective [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans [Line Items]
Target allocation	Generate a minimum annual inflation adjusted return of 5% and outperform a traditional 70/30 equities/bond portfolio.
Temporary Investment Funds [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans [Line Items]
Target allocation	Invests primarily in a diversified portfolio of investment grade money market instruments.
Temporary Investment Funds [Member] | Primary Investment Objective [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans [Line Items]
Target allocation	Achieve a market level of current income while maintaining stability of principal and liquidity.
Maximum [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans [Line Items]
Corporation's contributions	$ 300,000	$ 300,000
Contributions expected in 2025	$ 300,000
Defined benefit plan actuarial gain loss percentage	10.00%		10.00%
Minimum [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans [Line Items]
Defined benefit plan actuarial gain loss percentage	10.00%		10.00%
High-quality fixed-income investments maturity	10 years
Foreign Defined Benefits Pension Plans [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	$ 36,101,000	42,338,000	£ 28,800	£ 33,257
Accumulated benefit obligations	32,449,000	37,386,000	£ 25,887	£ 29,368
Defined contribution plan contribution required in current year	0	0
Defined contribution plan expected contribution required in 2024 to be fully funded	0
Contributions to defined contribution pension plan	267,000	235,000
Contributions to the defined contribution pension plan expected in 2025	$ 300,000
Number of additional defined benefit pension plans | Pension_Plan	2		2
Foreign Defined Benefits Pension Plans [Member] | Unfunded Plan [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans [Line Items]
Accumulated benefit obligations	$ 5,169,000	5,061,000
Defined Benefit Pension Plan [Member] | U.S. [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans [Line Items]
Number of defined benefit pension plans | Pension_Plan	1		1
Minimum contributions required	$ 5,438,000	339,000
Minimum contributions expected in 2025	3,000,000
Fair value of plan assets	158,704,000	163,929,000			$ 161,374,000
Accumulated benefit obligations	168,139,000	185,839,000
Actuarial gain impact from lump-sum window	977,000
Voluntary contributions made	6,206,000	1,108,000
Defined Benefit Pension Plan [Member] | U.S. [Member] | Alternative Investments - Managed Funds [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	6,081,000	6,035,000
Defined Benefit Pension Plan [Member] | Foreign Defined Benefits Pension Plans [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	36,101,000	42,338,000			$ 41,679,000
Voluntary contributions made	400,000	503,000
Defined Benefit Pension Plan [Member] | Ampco Pittsburgh [Member] | U.S. [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans [Line Items]
Minimum contributions expected in 2025	3,200,000
Voluntary contributions made	3,200,000	2,695,000
Nonqualified Defined Benefit Pension Plan [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans [Line Items]
Accumulated benefit obligations	8,022,000	8,526,000
Fair market value included in other noncurrent assets	3,026,000	3,245,000
Other Postretirement Benefit Plans [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans [Line Items]
Voluntary contributions made	$ 372,000	$ 423,000
Number of subsidiaries having postretirement health care benefits | Customer	2
Percentage decrease in other postretirement benefits in 2029	(4.75%)		(4.75%)
Year related to decrease in health care cost trend rate	2030
Other Postretirement Benefit Plans [Member] | Maximum [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans [Line Items]
Monthly reimbursement period	6 years