Financing Arrangements (Narrative) (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Apr. 30, 2017	Oct. 21, 2015	Aug. 13, 2015
Line of Credit Facility [Line Items]
Ownership percentage of domestic subsidiaries				100.00%
Lease agreement, capacity						$ 50,000,000.0
Finance leases	$ 18,700,000	$ 17,200,000
Foreign subsidiaries borrowings amount	13,000,000.0	16,200,000
Foreign subsidiaries bank guarantee amount	$ 34,900,000	$ 33,800,000
Weighted average interest rate	5.40%	5.80%	5.80%
Arkansas Development Finance Authority | Southwest Steel Processing LLC
Line of Credit Facility [Line Items]
Maximum borrowing capacity					$ 11,000,000.0
Credit facility outstanding	$ 6,900,000
Revolving credit facility
Line of Credit Facility [Line Items]
Senior notes, interest rate	1.35%
Debt outstanding	$ 143,700,000	$ 173,200,000
Foreign Line of Credit
Line of Credit Facility [Line Items]
Senior notes, interest rate	3.25%
Debt outstanding	$ 0	4,600,000
Senior Notes | Senior Notes Due 2027
Line of Credit Facility [Line Items]
Aggregate principal amount				$ 350,000,000.0
Senior Notes | Senior Notes due 2027
Line of Credit Facility [Line Items]
Senior notes, interest rate	6.625%			6.625%
Debt outstanding	$ 350,000,000.0	$ 350,000,000.0
Banco Bolbao Vizcaya Argentaria, S.A. | Line of Credit | Revolving credit facility | Financing Agreement
Line of Credit Facility [Line Items]
Maximum borrowing capacity	12,300,000
Credit facility outstanding	0
Banco Bolbao Vizcaya Argentaria, S.A. | Line of Credit | Foreign Line of Credit
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 30,700,000
Park-Ohio Industries, Inc. | Revolving credit facility | Seventh Amendment Credit Agreement
Line of Credit Facility [Line Items]
Maximum borrowing capacity			$ 350,000,000.0
Park-Ohio Industries, Inc. | Revolving credit facility | Amendment No. 1 to Seventh Amended And Restated Credit Agreement
Line of Credit Facility [Line Items]
Maximum borrowing capacity			375,000,000.0
Accordion feature, increase limit			100,000,000.0
Park-Ohio Industries, Inc. | Revolving credit facility, Canadian sub-limit | Seventh Amendment Credit Agreement
Line of Credit Facility [Line Items]
Maximum borrowing capacity			35,000,000.0
Park-Ohio Industries, Inc. | Revolving credit facility, Canadian sub-limit | Amendment No. 1 to Seventh Amended And Restated Credit Agreement
Line of Credit Facility [Line Items]
Maximum borrowing capacity			40,000,000.0
Park-Ohio Industries, Inc. | Revolving credit facility, European sub-limit | Seventh Amendment Credit Agreement
Line of Credit Facility [Line Items]
Maximum borrowing capacity			25,000,000.0
Park-Ohio Industries, Inc. | Revolving credit facility, European sub-limit | Amendment No. 1 to Seventh Amended And Restated Credit Agreement
Line of Credit Facility [Line Items]
Maximum borrowing capacity			$ 30,000,000.0