Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Components of basic and diluted earnings per share [Abstract]
Net earnings (loss) attributable to Modine	$ 15.9	$ (4.1)	$ 32.9	$ 4.5
Less: Undistributed earnings attributable to unvested shares	(0.1)	0.0	(0.3)	(0.1)
Net earnings (loss) available to Modine shareholders	$ 15.8	$ (4.1)	$ 32.6	$ 4.4
Weighted-average shares outstanding - basic (in shares)	49.8	47.1	49.6	47.0
Effect of dilutive securities (in shares)	0.9	0.0	0.8	0.3
Weighted-average shares outstanding - diluted (in shares)	50.7	47.1	50.4	47.3
Earnings per share [Abstract]
Net earnings (loss) per share - basic (in dollars per share)	$ 0.32	$ (0.09)	$ 0.66	$ 0.09
Net earnings (loss) per share - diluted (in dollars per share)	$ 0.31	$ (0.09)	$ 0.65	$ 0.09
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive securities (in shares)		0.4
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earning per share (in shares)	0.3	1.1	0.3	1.1