Revenue Recognition, Impacts of Adopting New Accounting Guidance (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Mar. 31, 2018
Consolidated Statement of Operations [Abstract]
Net sales	$ 548.9	$ 508.3	$ 1,115.0	$ 1,023.8
Net earnings attributable to Modine	$ 38.5	$ 15.9	$ 60.5	$ 32.9
Net earnings per share attributable to Modine shareholders [Abstract]
Basic (in dollars per share)	$ 0.76	$ 0.32	$ 1.19	$ 0.66
Diluted (in dollars per share)	$ 0.75	$ 0.31	$ 1.18	$ 0.65
ASSETS [Abstract]
Inventories	$ 210.6		$ 210.6		$ 191.3
Other current assets	68.4		68.4		70.1
Deferred income taxes	99.7		99.7		96.9
LIABILITIES AND SHAREHOLDERS' EQUITY [Abstract]
Deferred income taxes	8.7		8.7		9.9
Retained earnings	447.8		447.8		$ 394.9
Impact of New Accounting Guidance [Member] | ASU 2014-09 [Member]
Consolidated Statement of Operations [Abstract]
Net sales	1.6		0.4
Net earnings attributable to Modine	$ 0.3		$ 0.1
Net earnings per share attributable to Modine shareholders [Abstract]
Basic (in dollars per share)	$ 0		$ 0
Diluted (in dollars per share)	$ 0		$ 0
ASSETS [Abstract]
Inventories	$ 1.6		$ 1.6
Other current assets	(2.6)		(2.6)
Deferred income taxes	0.1		0.1
LIABILITIES AND SHAREHOLDERS' EQUITY [Abstract]
Deferred income taxes	(0.2)		(0.2)
Retained earnings	(0.7)		(0.7)
Results Without Impact of New Accounting Guidance [Member] | ASU 2014-09 [Member]
Consolidated Statement of Operations [Abstract]
Net sales	550.5		1,115.4
Net earnings attributable to Modine	$ 38.8		$ 60.6
Net earnings per share attributable to Modine shareholders [Abstract]
Basic (in dollars per share)	$ 0.76		$ 1.19
Diluted (in dollars per share)	$ 0.75		$ 1.18
ASSETS [Abstract]
Inventories	$ 212.2		$ 212.2
Other current assets	65.8		65.8
Deferred income taxes	99.8		99.8
LIABILITIES AND SHAREHOLDERS' EQUITY [Abstract]
Deferred income taxes	8.5		8.5
Retained earnings	$ 447.1		$ 447.1