Condensed Consolidated Statements of Income (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended				6 Months Ended		9 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Sep. 30, 2017	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Net sales	$ 414.3		$ 352.2				$ 1,252.2	$ 1,046.9
Cost of sales	348.4		295.5				1,048.1	875.4
Gross profit	65.9		56.7				204.1	171.5
Selling, general and administrative expenses	41.1		37.7				131.9	112.5
Gain on sale of assets	0.0		0.0				(1.9)	0.0
Litigation settlement gain	0.0		0.0				0.0	(3.3)
Operating income	24.8		19.0				74.1	62.3
Other components of pension income and other postretirement benefits expense, net	2.0		1.7				6.4	4.7
Interest expense, net	(8.9)		(7.8)				(26.1)	(23.1)
Loss on extinguishment of debt	0.0		0.0				0.0	(11.0)
Income before income taxes	17.9		12.9				54.4	32.9
Income tax expense	(3.2)		(2.7)				(14.5)	(9.4)
Net income	14.7		10.2				39.9	23.5
Net income attributable to noncontrolling interests	(0.5)		(0.2)				(1.1)	(0.7)
Net income attributable to Park-Ohio Holdings Corp. common shareholders	$ 14.2		$ 10.0				$ 38.8	$ 22.8
Earnings per common share attributable to Park-Ohio Holdings Corp. common shareholders:
Basic (in dollars per share)	$ 1.15		$ 0.82				$ 3.15	$ 1.87
Diluted (in dollars per share)	$ 1.14		$ 0.80				$ 3.09	$ 1.83
Weighted-average shares used to compute earnings per share:
Basic (in shares)	12.3		12.2				12.3	12.2
Diluted (in shares)	12.5		12.4				12.5	12.4
Dividends per common share (in dollars per share)		$ 0.125		$ 0.125	$ 0.375	$ 0.375