Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended				6 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Sep. 30, 2019	Jun. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Components of basic and diluted earnings per share [Abstract]
Net earnings (loss) attributable to Modine	$ 8.6	$ (8.6)	$ (4.7)	$ 8.0	$ 0.0	$ 3.3
Weighted-average shares outstanding - basic (in shares)	51.3		50.8		51.1	50.8
Effect of dilutive securities (in shares)	0.0		0.0		0.0	0.3
Weighted-average shares outstanding - diluted (in shares)	51.3		50.8		51.1	51.1
Earnings (loss) per share [Abstract]
Net earnings (loss) per share - basic (in dollars per share)	$ 0.17		$ (0.09)		$ 0	$ 0.07
Net earnings (loss) per share - diluted (in dollars per share)	$ 0.17		$ (0.09)		$ 0	$ 0.06
Antidilutive securities excluded from computation of earning per share [Abstract]
Potentially dilutive securities not included in computation of diluted net loss per share (in shares)			0.3
Stock Options [Member]
Antidilutive securities excluded from computation of earning per share [Abstract]
Antidilutive securities excluded from computation of earning per share (in shares)	1.0		0.9		1.1	0.8
Restricted Stock [Member]
Antidilutive securities excluded from computation of earning per share [Abstract]
Antidilutive securities excluded from computation of earning per share (in shares)	0.4		0.5		0.4	0.5