Financing Arrangements (Narrative) (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Apr. 30, 2017	Dec. 21, 2016	Oct. 21, 2015	Aug. 13, 2015
Line of Credit Facility [Line Items]
Ownership percentage of domestic subsidiaries				100.00%
Finance leases		$ 20,700,000					$ 50,000,000
Finance leases	$ 17,200,000
Foreign subsidiaries borrowings amount	16,200,000	26,100,000
Foreign subsidiaries bank guarantee amount	$ 33,800,000	$ 27,500,000
Weighted average interest rate	5.80%	5.80%	6.10%
Arkansas Development Finance Authority | Southwest Steel Processing LLC
Line of Credit Facility [Line Items]
Maximum borrowing capacity						$ 11,000,000.0
Amount outstanding	$ 8,400,000
Revolving credit facility
Line of Credit Facility [Line Items]
Senior notes, interest rate	2.85%
Amount outstanding	$ 173,200,000	$ 165,100,000
Foreign Line of Credit
Line of Credit Facility [Line Items]
Senior notes, interest rate	3.25%
Amount outstanding	$ 4,600,000	12,600,000
Senior Notes | Senior Notes Due 2027
Line of Credit Facility [Line Items]
Aggregate principal amount				$ 350,000,000.0
Senior Notes | Senior Notes 6.625% Due 2027
Line of Credit Facility [Line Items]
Senior notes, interest rate	6.625%		6.625%	6.625%
Amount outstanding	$ 350,000,000	350,000,000
Banco Bolbao Vizcaya Argentaria, S.A. | Line of Credit | Revolving credit facility | Financing Agreement
Line of Credit Facility [Line Items]
Maximum borrowing capacity					$ 11,200,000.0
Amount outstanding	$ 0
Banco Bolbao Vizcaya Argentaria, S.A. | Line of Credit | Foreign Line of Credit
Line of Credit Facility [Line Items]
Maximum borrowing capacity					$ 28,100,000.0
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, 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
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