Supplemental Guarantor Information (Condensed Consolidating Balance Sheets) (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 72.6	$ 54.4	$ 49.5	$ 48.4
Accounts receivable, net	231.4	194.4
Inventories, net	268.3	240.6
Receivable from affiliates	17.2	12.8
Other current assets	70.3	53.3
Total current assets	659.8	555.5
Investments in subsidiaries	0.0	0.0
Intercompany advances	0.0	0.0
Property, plant and equipment, net	173.7	169.6
Goodwill	92.0	86.6
Intangible assets, net	97.5	96.6
Other long-term assets	79.3	71.3
Total assets	1,102.3	979.6
Current liabilities:
Trade accounts payable	169.4	133.7
Payable to affiliates	7.1	7.0
Current portion of long-term debt and short-term debt	18.1	30.8
Accrued expenses and other	89.2	78.6
Total current liabilities	283.8	250.1
Long-term liabilities, less current portion:
Debt	492.3	439.0
Deferred income taxes	29.0	29.0
Other long-term liabilities	21.3	29.8
Total long-term liabilities	542.6	497.8
Intercompany advances	0.0	0.0
Total Park-Ohio Industries, Inc. and Subsidiaries shareholder's equity	265.5	221.7
Noncontrolling interests	10.4	10.0
Total equity	275.9	231.7
Total liabilities and shareholder's equity	1,102.3	979.6
Reportable Legal Entities | Parent
Current assets:
Cash and cash equivalents	0.0	0.0	0.0	0.0
Accounts receivable, net	0.0	0.0
Inventories, net	0.0	0.0
Receivable from affiliates	0.0	0.0
Other current assets	0.6	0.7
Total current assets	0.6	0.7
Investments in subsidiaries	546.4	492.8
Intercompany advances	300.1	296.5
Property, plant and equipment, net	6.1	6.2
Goodwill	0.0	0.0
Intangible assets, net	0.0	0.0
Other long-term assets	67.1	62.8
Total assets	920.3	859.0
Current liabilities:
Trade accounts payable	0.0	0.0
Payable to affiliates	0.0	0.0
Current portion of long-term debt and short-term debt	0.0	13.2
Accrued expenses and other	13.4	10.5
Total current liabilities	13.4	23.7
Long-term liabilities, less current portion:
Debt	442.7	389.2
Deferred income taxes	0.0	0.0
Other long-term liabilities	15.2	16.1
Total long-term liabilities	457.9	405.3
Intercompany advances	173.1	198.3
Total Park-Ohio Industries, Inc. and Subsidiaries shareholder's equity	265.5	221.7
Noncontrolling interests	10.4	10.0
Total equity	275.9	231.7
Total liabilities and shareholder's equity	920.3	859.0
Reportable Legal Entities | Combined Guarantor Subsidiaries
Current assets:
Cash and cash equivalents	0.0	0.0	0.0	0.1
Accounts receivable, net	150.6	125.2
Inventories, net	190.2	172.9
Receivable from affiliates	0.0	0.0
Other current assets	40.2	28.3
Total current assets	381.0	326.4
Investments in subsidiaries	249.4	213.8
Intercompany advances	83.0	78.1
Property, plant and equipment, net	101.5	98.2
Goodwill	58.9	56.8
Intangible assets, net	61.3	64.8
Other long-term assets	4.6	4.5
Total assets	939.7	842.6
Current liabilities:
Trade accounts payable	122.8	100.3
Payable to affiliates	0.0	0.0
Current portion of long-term debt and short-term debt	6.6	6.4
Accrued expenses and other	35.0	36.8
Total current liabilities	164.4	143.5
Long-term liabilities, less current portion:
Debt	10.6	12.2
Deferred income taxes	19.4	20.4
Other long-term liabilities	1.0	8.5
Total long-term liabilities	31.0	41.1
Intercompany advances	226.6	192.2
Total Park-Ohio Industries, Inc. and Subsidiaries shareholder's equity	517.7	465.8
Noncontrolling interests	0.0	0.0
Total equity	517.7	465.8
Total liabilities and shareholder's equity	939.7	842.6
Reportable Legal Entities | Combined Non-Guarantor Subsidiaries
Current assets:
Cash and cash equivalents	72.6	54.4	49.5	48.3
Accounts receivable, net	80.8	69.2
Inventories, net	78.1	67.7
Receivable from affiliates	17.2	12.8
Other current assets	29.5	24.3
Total current assets	278.2	228.4
Investments in subsidiaries	0.0	0.0
Intercompany advances	107.2	110.5
Property, plant and equipment, net	66.1	65.2
Goodwill	33.1	29.8
Intangible assets, net	36.2	31.8
Other long-term assets	7.6	4.0
Total assets	528.4	469.7
Current liabilities:
Trade accounts payable	46.6	33.4
Payable to affiliates	7.1	7.0
Current portion of long-term debt and short-term debt	11.5	11.2
Accrued expenses and other	40.8	31.3
Total current liabilities	106.0	82.9
Long-term liabilities, less current portion:
Debt	39.0	37.6
Deferred income taxes	9.6	8.6
Other long-term liabilities	5.1	5.2
Total long-term liabilities	53.7	51.4
Intercompany advances	90.6	94.6
Total Park-Ohio Industries, Inc. and Subsidiaries shareholder's equity	267.7	230.8
Noncontrolling interests	10.4	10.0
Total equity	278.1	240.8
Total liabilities and shareholder's equity	528.4	469.7
Reclassifications/ Eliminations
Current assets:
Cash and cash equivalents	0.0	0.0	$ 0.0	$ 0.0
Accounts receivable, net	0.0	0.0
Inventories, net	0.0	0.0
Receivable from affiliates	0.0	0.0
Other current assets	0.0	0.0
Total current assets	0.0	0.0
Investments in subsidiaries	(795.8)	(706.6)
Intercompany advances	(490.3)	(485.1)
Property, plant and equipment, net	0.0	0.0
Goodwill	0.0	0.0
Intangible assets, net	0.0	0.0
Other long-term assets	0.0	0.0
Total assets	(1,286.1)	(1,191.7)
Current liabilities:
Trade accounts payable	0.0	0.0
Payable to affiliates	0.0	0.0
Current portion of long-term debt and short-term debt	0.0	0.0
Accrued expenses and other	0.0	0.0
Total current liabilities	0.0	0.0
Long-term liabilities, less current portion:
Debt	0.0	0.0
Deferred income taxes	0.0	0.0
Other long-term liabilities	0.0	0.0
Total long-term liabilities	0.0	0.0
Intercompany advances	(490.3)	(485.1)
Total Park-Ohio Industries, Inc. and Subsidiaries shareholder's equity	(785.4)	(696.6)
Noncontrolling interests	(10.4)	(10.0)
Total equity	(795.8)	(706.6)
Total liabilities and shareholder's equity	$ (1,286.1)	$ (1,191.7)