Financing Arrangements (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Jun. 30, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2015
Line of Credit Facility [Line Items]
Percentage ownership	100.00%
Finance lease agreement, amount					$ 50,000,000.0
Southwest Steel Processing LLC | Arkansas Development Finance Authority
Line of Credit Facility [Line Items]
Maximum borrowing capacity					$ 11,000,000.0
Borrowings outstanding		$ 7,800,000
Machinery and Equipment
Line of Credit Facility [Line Items]
Finance lease obligations		$ 16,700,000
Senior Notes Due 2027 | Senior Notes | Park-Ohio Industries, Inc.
Line of Credit Facility [Line Items]
Aggregate principal amount	$ 350,000,000.0
Stated interest rate	6.625%
Revolving credit facility
Line of Credit Facility [Line Items]
Stated interest rate		1.37%
Revolving credit facility | Seventh Amendment Credit Agreement | Park-Ohio Industries, Inc.
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 350,000,000.0
Revolving credit facility | Amendment No. 1 to Seventh Amended and Restated Credit Agreement | Park-Ohio Industries, Inc.
Line of Credit Facility [Line Items]
Maximum borrowing capacity				$ 375,000,000.0
Increase in additional borrowing capacity				100,000,000.0
Bank guarantees and letters of credit outstanding		$ 30,600,000	$ 33,800,000
Revolving credit facility | Financing Agreement | Line of Credit | Banco Bolbao Vizcaya Argentaria, S.A.
Line of Credit Facility [Line Items]
Maximum borrowing capacity		11,200,000
Borrowings outstanding		$ 0
Revolving Credit Facility Canadian Sub-Limit | Seventh Amendment Credit Agreement | Park-Ohio Industries, Inc.
Line of Credit Facility [Line Items]
Maximum borrowing capacity	35,000,000.0
Revolving Credit Facility Canadian Sub-Limit | Amendment No. 1 to Seventh Amended and Restated Credit Agreement | Park-Ohio Industries, Inc.
Line of Credit Facility [Line Items]
Maximum borrowing capacity				40,000,000.0
Revolving Credit Facility European Sub-Limit | Seventh Amendment Credit Agreement | Park-Ohio Industries, Inc.
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 25,000,000.0
Revolving Credit Facility European Sub-Limit | Amendment No. 1 to Seventh Amended and Restated Credit Agreement | Park-Ohio Industries, Inc.
Line of Credit Facility [Line Items]
Maximum borrowing capacity				$ 30,000,000.0
Industrial Equipment Group European Facilities
Line of Credit Facility [Line Items]
Stated interest rate		3.25%
Industrial Equipment Group European Facilities | Line of Credit | Banco Bolbao Vizcaya Argentaria, S.A.
Line of Credit Facility [Line Items]
Maximum borrowing capacity		$ 28,000,000.0