Selected Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Net sales	$ 366.0	$ 352.2	$ 350.9	$ 343.8	$ 306.8	$ 312.7	$ 329.4	$ 328.0	$ 1,412.9	$ 1,276.9	$ 1,463.8
Gross profit	61.6	57.2	60.3	55.5	46.6	54.3	54.3	47.8	234.6	203.0	235.2
Net income	6.0	10.2	3.2	10.1	6.7	13.8	9.0	2.7	29.5	32.2	48.7
Net income attributable to noncontrolling interest	(0.2)	(0.2)	(0.2)	(0.3)	(0.2)	(0.3)	0.0	0.0	(0.9)	(0.5)	(0.6)
Net income attributable to ParkOhio common shareholders	$ 5.8	$ 10.0	$ 3.0	$ 9.8	$ 6.5	$ 13.5	$ 9.0	$ 2.7	$ 28.6	$ 31.7	$ 48.1
Earnings per common share attributable to ParkOhio common shareholders:
Basic (in dollars per share)	$ 0.48	$ 0.82	$ 0.25	$ 0.80	$ 0.53	$ 1.12	$ 0.74	$ 0.22	$ 2.34	$ 2.62	$ 3.94
Diluted (in dollars per share)	0.46	0.80	0.24	0.79	0.53	1.10	0.73	0.22	2.30	2.58	3.88
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
Litigation settlement gain				$ 3.3					$ 3.3	$ 0.0	$ (2.2)
Loss on extinguishment of debt									11.0	0.0	0.0
Net impact of U.S. Tax Act	$ 4.2								4.2	0.0	0.0
Asset impairment charge								$ 4.0	$ 0.0	$ 4.0	$ 0.0
Senior Notes 8.125% Due 2021 | Senior Notes
Earnings per common share attributable to ParkOhio common shareholders:
Loss on extinguishment of debt			$ 11.0