Consolidated Statements of Income - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Net sales	$ 405.9	$ 414.3	$ 432.2	$ 405.7	$ 366.0	$ 352.2	$ 350.9	$ 343.8	$ 1,658.1	$ 1,412.9	$ 1,276.9
Cost of sales									1,386.6	1,180.1	1,075.7
Gross profit	67.4	65.9	73.1	65.1	61.3	56.7	59.8	55.0	271.5	232.8	201.2
Selling, general and administrative expenses									176.1	152.3	134.2
Gain on sale of assets			(1.9)						(1.9)	0.0	0.0
Litigation settlement gain								(3.3)	0.0	(3.3)	0.0
Asset impairment charge									0.0	0.0	4.0
Operating income									97.3	83.8	63.0
Other components of pension income and other postretirement benefits expense, net									8.8	6.4	6.2
Interest expense, net									(34.3)	(31.5)	(28.2)
Loss on extinguishment of debt							(11.0)		0.0	(11.0)	0.0
Income before income taxes									71.8	47.7	41.0
Income tax expense									(16.6)	(18.2)	(8.8)
Net income	15.3	14.7	15.0	10.2	6.0	10.2	3.2	10.1	55.2	29.5	32.2
Net income attributable to noncontrolling interest	(0.5)	(0.5)	(0.2)	(0.4)	(0.2)	(0.2)	(0.2)	(0.3)	(1.6)	(0.9)	(0.5)
Net income attributable to ParkOhio common shareholders	$ 14.8	$ 14.2	$ 14.8	$ 9.8	$ 5.8	$ 10.0	$ 3.0	$ 9.8	$ 53.6	$ 28.6	$ 31.7
Earnings per common share attributable to ParkOhio common shareholders:
Basic (in dollars per share)	$ 1.21	$ 1.15	$ 1.20	$ 0.80	$ 0.48	$ 0.82	$ 0.25	$ 0.80	$ 4.37	$ 2.34	$ 2.62
Diluted (in dollars per share)	$ 1.19	$ 1.14	$ 1.18	$ 0.78	$ 0.46	$ 0.80	$ 0.24	$ 0.79	$ 4.28	$ 2.30	$ 2.58
Weighted-average shares used to compute earnings per share:
Basic (in shares)									12,255,490	12,211,978	12,126,264
Diluted (in shares)									12,508,513	12,455,941	12,274,452