Selected Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 360.4	$ 340.2	$ 228.3	$ 366.3	$ 379.5	$ 403.4	$ 415.3	$ 420.1	$ 1,295.2	$ 1,618.3	$ 1,658.1
Gross profit	50.8	49.7	14.2	53.9	62.3	66.5	66.2	65.3	168.6	260.3	271.5
Net income (loss)	5.7	5.2	(17.0)	1.3	7.7	12.4	7.9	11.7	(4.8)	39.7	55.2
Net loss (income) attributable to noncontrolling interest	(0.1)	0.1	0.4	(0.1)	(0.1)	(0.2)	(0.3)	(0.5)	0.3	(1.1)	(1.6)
Net (loss) income attributable to ParkOhio common shareholders	$ 5.6	$ 5.3	$ (16.6)	$ 1.2	$ 7.6	$ 12.2	$ 7.6	$ 11.2	$ (4.5)	$ 38.6	$ 53.6
Earnings (loss) per common share attributable to ParkOhio common shareholders:
Basic (in dollars per share)	$ 0.46	$ 0.44	$ (1.38)	$ 0.10	$ 0.62	$ 1.00	$ 0.62	$ 0.92	$ (0.37)	$ 3.16	$ 4.37
Diluted (in dollars per share)	0.45	0.44	(1.38)	0.10	0.61	0.99	0.61	0.90	(0.37)	3.12	4.28
Cash dividends per common share (in dollars per share)	$ 0.125	$ 0	$ 0	$ 0.125	$ 0.125	$ 0.125	$ 0.125	$ 0.125	$ 0.25	$ 0.50	$ 0.50
Retirement and resignation of former President							$ 4.3