Supplemental Guarantor Information (Consolidating Statements of Income (Loss) and Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended				9 Months Ended
	Sep. 30, 2017	Mar. 31, 2017	Sep. 30, 2016	Mar. 31, 2016	Sep. 30, 2017	Sep. 30, 2016
Consolidating statement of operations
Net sales	$ 352.2		$ 312.7		$ 1,046.9	$ 970.1
Cost of sales	295.0		258.4		873.9	813.7
Gross profit	57.2		54.3		173.0	156.4
Selling, general and administrative expenses	36.2		33.2		108.8	99.0
Asset impairment	0.0		0.0	$ 4.0	0.0	4.0
Litigation settlement gain	0.0	$ (3.3)	0.0		(3.3)	0.0
Income (loss) from subsidiaries	0.0		0.0		0.0	0.0
Operating income (loss)	21.0		21.1		67.5	53.4
Interest expense	7.8		7.2		23.1	21.3
Loss on extinguishment of debt	0.0		0.0		11.0	0.0
Income (loss) before income taxes	13.2		13.9		33.4	32.1
Income tax expense	2.8		0.0		9.6	6.1
Net income (loss)	10.4		13.9		23.8	26.0
Net (income) loss attributable to noncontrolling interests	(0.2)		(0.3)		(0.7)	(0.3)
Net income attributable to Park-Ohio Industries Inc. common shareholder	10.2		13.6		23.1	25.7
Other comprehensive income (loss)
Foreign currency translation adjustment	7.5		(1.3)		18.9	(5.3)
Pension and OPEB activity, net of tax adjustments	0.2		0.3		0.6	0.7
Total comprehensive income, net of tax	18.1		12.9		43.3	21.4
Comprehensive (income) loss attributable to noncontrolling interest	(0.2)		(0.3)		(0.7)	(0.3)
Comprehensive income attributable to Park-Ohio Industries Inc. common shareholder	17.9		12.6		42.6	21.1
Reportable Legal Entities | Parent
Consolidating statement of operations
Net sales	0.0		0.0		0.0	0.0
Cost of sales	0.0		0.0		0.0	0.0
Gross profit	0.0		0.0		0.0	0.0
Selling, general and administrative expenses	7.0		7.7		19.5	18.0
Asset impairment						0.0
Litigation settlement gain					0.0
Income (loss) from subsidiaries	24.6		28.4		75.4	64.2
Operating income (loss)	17.6		20.7		55.9	46.2
Interest expense	7.2		6.8		21.1	20.2
Loss on extinguishment of debt	0.0				11.0
Income (loss) before income taxes	10.4		13.9		23.8	26.0
Income tax expense	0.0		0.0		0.0	0.0
Net income (loss)	10.4		13.9		23.8	26.0
Net (income) loss attributable to noncontrolling interests	(0.2)		(0.3)		(0.7)	(0.3)
Net income attributable to Park-Ohio Industries Inc. common shareholder	10.2		13.6		23.1	25.7
Other comprehensive income (loss)
Foreign currency translation adjustment	7.5		(1.3)		18.9	(5.3)
Pension and OPEB activity, net of tax adjustments	0.2		0.3		0.6	0.7
Total comprehensive income, net of tax	18.1		12.9		43.3	21.4
Comprehensive (income) loss attributable to noncontrolling interest	(0.2)		(0.3)		(0.7)	(0.3)
Comprehensive income attributable to Park-Ohio Industries Inc. common shareholder	17.9		12.6		42.6	21.1
Reportable Legal Entities | Combined Guarantor Subsidiaries
Consolidating statement of operations
Net sales	258.4		242.1		774.6	751.7
Cost of sales	220.6		205.3		660.1	645.8
Gross profit	37.8		36.8		114.5	105.9
Selling, general and administrative expenses	18.4		17.8		55.7	54.3
Asset impairment						4.0
Litigation settlement gain					(3.3)
Income (loss) from subsidiaries	6.8		5.8		16.1	13.9
Operating income (loss)	26.2		24.8		78.2	61.5
Interest expense	0.0		0.0		0.0	0.0
Loss on extinguishment of debt	0.0				0.0
Income (loss) before income taxes	26.2		24.8		78.2	61.5
Income tax expense	1.9		(3.0)		4.0	(1.3)
Net income (loss)	24.3		27.8		74.2	62.8
Net (income) loss attributable to noncontrolling interests	0.0		0.0		0.0	0.0
Net income attributable to Park-Ohio Industries Inc. common shareholder	24.3		27.8		74.2	62.8
Other comprehensive income (loss)
Foreign currency translation adjustment	0.0		0.0		0.0	0.0
Pension and OPEB activity, net of tax adjustments	0.2		0.0		0.6	0.4
Total comprehensive income, net of tax	24.5		27.8		74.8	63.2
Comprehensive (income) loss attributable to noncontrolling interest	0.0		0.0		0.0	0.0
Comprehensive income attributable to Park-Ohio Industries Inc. common shareholder	24.5		27.8		74.8	63.2
Reportable Legal Entities | Combined Non-Guarantor Subsidiaries
Consolidating statement of operations
Net sales	93.8		70.6		272.3	218.4
Cost of sales	74.4		53.1		213.8	167.9
Gross profit	19.4		17.5		58.5	50.5
Selling, general and administrative expenses	10.8		7.7		33.6	26.7
Asset impairment						0.0
Litigation settlement gain					0.0
Income (loss) from subsidiaries	0.0		0.0		0.0	0.0
Operating income (loss)	8.6		9.8		24.9	23.8
Interest expense	0.6		0.4		2.0	1.1
Loss on extinguishment of debt	0.0				0.0
Income (loss) before income taxes	8.0		9.4		22.9	22.7
Income tax expense	0.9		3.0		5.6	7.4
Net income (loss)	7.1		6.4		17.3	15.3
Net (income) loss attributable to noncontrolling interests	(0.2)		(0.3)		(0.7)	(0.3)
Net income attributable to Park-Ohio Industries Inc. common shareholder	6.9		6.1		16.6	15.0
Other comprehensive income (loss)
Foreign currency translation adjustment	7.5		(1.3)		18.9	(5.3)
Pension and OPEB activity, net of tax adjustments	0.0		0.0		0.0	0.0
Total comprehensive income, net of tax	14.6		5.1		36.2	10.0
Comprehensive (income) loss attributable to noncontrolling interest	(0.2)		(0.3)		(0.7)	(0.3)
Comprehensive income attributable to Park-Ohio Industries Inc. common shareholder	14.4		4.8		35.5	9.7
Reclassifications/ Eliminations
Consolidating statement of operations
Net sales	0.0		0.0		0.0	0.0
Cost of sales	0.0		0.0		0.0	0.0
Gross profit	0.0		0.0		0.0	0.0
Selling, general and administrative expenses	0.0		0.0		0.0	0.0
Asset impairment						0.0
Litigation settlement gain					0.0
Income (loss) from subsidiaries	(31.4)		(34.2)		(91.5)	(78.1)
Operating income (loss)	(31.4)		(34.2)		(91.5)	(78.1)
Interest expense	0.0		0.0		0.0	0.0
Loss on extinguishment of debt	0.0				0.0
Income (loss) before income taxes	(31.4)		(34.2)		(91.5)	(78.1)
Income tax expense	0.0		0.0		0.0	0.0
Net income (loss)	(31.4)		(34.2)		(91.5)	(78.1)
Net (income) loss attributable to noncontrolling interests	0.2		0.3		0.7	0.3
Net income attributable to Park-Ohio Industries Inc. common shareholder	(31.2)		(33.9)		(90.8)	(77.8)
Other comprehensive income (loss)
Foreign currency translation adjustment	(7.5)		1.3		(18.9)	5.3
Pension and OPEB activity, net of tax adjustments	(0.2)		0.0		(0.6)	(0.4)
Total comprehensive income, net of tax	(39.1)		(32.9)		(111.0)	(73.2)
Comprehensive (income) loss attributable to noncontrolling interest	0.2		0.3		0.7	0.3
Comprehensive income attributable to Park-Ohio Industries Inc. common shareholder	$ (38.9)		$ (32.6)		$ (110.3)	$ (72.9)