Supplemental Guarantor Information (Consolidating Statements of Income (Loss) and Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Mar. 31, 2017	Jun. 30, 2018	Jun. 30, 2017
Consolidating statement of operations
Net sales	$ 432.2	$ 350.9		$ 837.9	$ 694.7
Cost of sales	359.1	291.1		699.7	579.9
Gross profit	73.1	59.8		138.2	114.8
Selling, general and administrative expenses	47.6	37.0		90.4	74.7
Litigation settlement gain	0.0	0.0	$ (3.3)	0.0	(3.3)
Income (loss) from subsidiaries	0.0	0.0		0.0	0.0
Operating income (loss)	25.5	22.8		47.8	43.4
Other components of pension income and other postretirement benefits expense, net	2.1	1.5		4.4	3.1
Gain on sale of assets	1.9	0.0		1.9	0.0
Interest expense	(8.8)	(7.9)		(17.2)	(15.3)
Loss on extinguishment of debt	0.0	(11.0)		0.0	(11.0)
Income (loss) before income taxes	20.7	5.4		36.9	20.2
Income tax expense	(5.5)	(2.1)		(11.3)	(6.8)
Net income (loss)	15.2	3.3		25.6	13.4
Net (income) loss attributable to noncontrolling interests	(0.2)	(0.2)		(0.6)	(0.5)
Net income attributable to Park-Ohio Industries Inc. common shareholder	15.0	3.1		25.0	12.9
Other comprehensive income (loss)
Currency translation	(10.3)	7.5		(6.2)	11.5
Pension and OPEB activity, net of tax adjustments	0.0	0.2		1.4	0.4
Total comprehensive income, net of tax	4.9	11.0		20.8	25.3
Comprehensive (income) loss attributable to noncontrolling interest	(0.2)	(0.2)		(0.6)	(0.5)
Comprehensive income attributable to Park-Ohio Industries Inc. common shareholder	4.7	10.8		20.2	24.8
Reportable Legal Entities | Parent
Consolidating statement of operations
Net sales	0.0	0.0		0.0	0.0
Cost of sales	0.8	0.5		1.5	1.0
Gross profit	(0.8)	(0.5)		(1.5)	(1.0)
Selling, general and administrative expenses	16.0	7.2		25.4	14.6
Litigation settlement gain					0.0
Income (loss) from subsidiaries	38.0	27.6		63.9	50.8
Operating income (loss)	21.2	19.9		37.0	35.2
Other components of pension income and other postretirement benefits expense, net	2.1	1.5		4.4	3.1
Gain on sale of assets	0.0			0.0
Interest expense	(8.1)	(7.1)		(15.8)	(13.9)
Loss on extinguishment of debt		(11.0)			(11.0)
Income (loss) before income taxes	15.2	3.3		25.6	13.4
Income tax expense	0.0	0.0		0.0	0.0
Net income (loss)	15.2	3.3		25.6	13.4
Net (income) loss attributable to noncontrolling interests	(0.2)	(0.2)		(0.6)	(0.5)
Net income attributable to Park-Ohio Industries Inc. common shareholder	15.0	3.1		25.0	12.9
Other comprehensive income (loss)
Currency translation	(10.3)	7.5		(6.2)	11.5
Pension and OPEB activity, net of tax adjustments	0.0	0.2		1.4	0.4
Total comprehensive income, net of tax	4.9	11.0		20.8	25.3
Comprehensive (income) loss attributable to noncontrolling interest	(0.2)	(0.2)		(0.6)	(0.5)
Comprehensive income attributable to Park-Ohio Industries Inc. common shareholder	4.7	10.8		20.2	24.8
Reportable Legal Entities | Combined Guarantor Subsidiaries
Consolidating statement of operations
Net sales	319.8	256.9		611.1	516.2
Cost of sales	269.8	216.7		516.7	439.5
Gross profit	50.0	40.2		94.4	76.7
Selling, general and administrative expenses	23.2	18.3		45.8	37.3
Litigation settlement gain					(3.3)
Income (loss) from subsidiaries	12.1	4.9		17.8	9.3
Operating income (loss)	38.9	26.8		66.4	52.0
Other components of pension income and other postretirement benefits expense, net	0.0	0.0		0.0	0.0
Gain on sale of assets	1.9			1.9
Interest expense	0.0	0.0		0.0	0.0
Loss on extinguishment of debt		0.0			0.0
Income (loss) before income taxes	40.8	26.8		68.3	52.0
Income tax expense	(3.5)	0.4		(5.7)	(2.1)
Net income (loss)	37.3	27.2		62.6	49.9
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	37.3	27.2		62.6	49.9
Other comprehensive income (loss)
Currency translation	0.0	0.0		0.0	0.0
Pension and OPEB activity, net of tax adjustments	0.0	0.2		1.4	0.4
Total comprehensive income, net of tax	37.3	27.4		64.0	50.3
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	37.3	27.4		64.0	50.3
Reportable Legal Entities | Combined Non-Guarantor Subsidiaries
Consolidating statement of operations
Net sales	112.4	94.0		226.8	178.5
Cost of sales	88.5	73.9		181.5	139.4
Gross profit	23.9	20.1		45.3	39.1
Selling, general and administrative expenses	8.4	11.5		19.2	22.8
Litigation settlement gain					0.0
Income (loss) from subsidiaries	0.0	0.0		0.0	0.0
Operating income (loss)	15.5	8.6		26.1	16.3
Other components of pension income and other postretirement benefits expense, net	0.0	0.0		0.0	0.0
Gain on sale of assets	0.0			0.0
Interest expense	(0.7)	(0.8)		(1.4)	(1.4)
Loss on extinguishment of debt		0.0			0.0
Income (loss) before income taxes	14.8	7.8		24.7	14.9
Income tax expense	(2.0)	(2.5)		(5.6)	(4.7)
Net income (loss)	12.8	5.3		19.1	10.2
Net (income) loss attributable to noncontrolling interests	(0.2)	(0.2)		(0.6)	(0.5)
Net income attributable to Park-Ohio Industries Inc. common shareholder	12.6	5.1		18.5	9.7
Other comprehensive income (loss)
Currency translation	(10.3)	7.5		(6.2)	11.5
Pension and OPEB activity, net of tax adjustments	0.0	0.0		0.0	0.0
Total comprehensive income, net of tax	2.5	12.8		12.9	21.7
Comprehensive (income) loss attributable to noncontrolling interest	(0.2)	(0.2)		(0.6)	(0.5)
Comprehensive income attributable to Park-Ohio Industries Inc. common shareholder	2.3	12.6		12.3	21.2
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
Litigation settlement gain					0.0
Income (loss) from subsidiaries	(50.1)	(32.5)		(81.7)	(60.1)
Operating income (loss)	(50.1)	(32.5)		(81.7)	(60.1)
Other components of pension income and other postretirement benefits expense, net	0.0	0.0		0.0	0.0
Gain on sale of assets	0.0			0.0
Interest expense	0.0	0.0		0.0	0.0
Loss on extinguishment of debt		0.0			0.0
Income (loss) before income taxes	(50.1)	(32.5)		(81.7)	(60.1)
Income tax expense	0.0	0.0		0.0	0.0
Net income (loss)	(50.1)	(32.5)		(81.7)	(60.1)
Net (income) loss attributable to noncontrolling interests	0.2	0.2		0.6	0.5
Net income attributable to Park-Ohio Industries Inc. common shareholder	(49.9)	(32.3)		(81.1)	(59.6)
Other comprehensive income (loss)
Currency translation	10.3	(7.5)		6.2	(11.5)
Pension and OPEB activity, net of tax adjustments	0.0	(0.2)		(1.4)	(0.4)
Total comprehensive income, net of tax	(39.8)	(40.2)		(76.9)	(72.0)
Comprehensive (income) loss attributable to noncontrolling interest	0.2	0.2		0.6	0.5
Comprehensive income attributable to Park-Ohio Industries Inc. common shareholder	$ (39.6)	$ (40.0)		$ (76.3)	$ (71.5)