Selected Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 379.5	$ 403.4	$ 415.3	$ 420.1	$ 405.9	$ 414.3	$ 432.2	$ 405.7	$ 1,618.3	$ 1,658.1	$ 1,412.9
Gross profit	62.3	66.5	66.2	65.3	67.4	65.9	73.1	65.1	260.3	271.5	232.8
Net income	7.7	12.4	7.9	11.7	15.3	14.7	15.0	10.2	39.7	55.2	29.5
Net income attributable to noncontrolling interest	(0.1)	(0.2)	(0.3)	(0.5)	(0.5)	(0.5)	(0.2)	(0.4)	(1.1)	(1.6)	(0.9)
Net income attributable to ParkOhio common shareholders	$ 7.6	$ 12.2	$ 7.6	$ 11.2	$ 14.8	$ 14.2	$ 14.8	$ 9.8	$ 38.6	$ 53.6	$ 28.6
Earnings per common share attributable to ParkOhio common shareholders:
Basic (in dollars per share)	$ 0.62	$ 1.00	$ 0.62	$ 0.92	$ 1.21	$ 1.15	$ 1.20	$ 0.80	$ 3.16	$ 4.37	$ 2.34
Diluted (in dollars per share)	0.61	0.99	0.61	0.90	1.19	1.14	1.18	0.78	3.12	4.28	2.30
Cash dividends per common share (in dollars per share)	$ 0.125000	$ 0.125000	$ 0.125000	$ 0.125	$ 0.125	$ 0.125	$ 0.125	$ 0.125	$ 0.5	$ 0.5	$ 0.5
Retirement and resignation of former President			$ 4.3
Gain on sale of assets							$ 1.9		$ 0.0	$ 1.9	$ 0.0