Pension and Employee Benefit Plans (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011
Defined Benefit Plan Disclosure [Line Items]
Portion of employee contribution which is matched (in hundredths)	50.00%	50.00%	50.00%
Contribution by employee (in hundredths)	5.00%	5.00%	5.00%
Defined contribution plan cost recognized	$ 4.1	$ 4.4	$ 4.3
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit plan curtailment charge			1.6
Change in benefit obligation [Roll Forward]
Benefit obligation at beginning of year	281.8	246.0
Service cost	0.6	1.4	1.9
Interest cost	13.5	13.9	13.7
Actuarial loss	27.1	35.6
Benefits paid	(12.6)	(13.8)
Settlement Curtailment adjustment	0	0
Currency translation adjustment	(0.8)	(1.3)
Benefit obligation at end of year	309.6	281.8	246.0
Change in plan assets [Roll Forward]
Fair value of plan assets at beginning of year	186.6	182.1
Actual return on plan assets	16.2	5.5
Benefits paid	(12.6)	(13.8)
Employer contributions	10.4	12.8
Fair value of plan assets at end of year	200.6	186.6	182.1
Funded status at end of year	(109.0)	(95.2)
Amounts recognized in the consolidated balance sheet consist of [Abstract]
Current liability	(1.0)	(1.1)
Noncurrent liability	(108.0)	(94.1)
Total liability	(109.0)	(95.2)
Amounts recognized in accumulated other comprehensive loss consist of [Abstract]
Net actuarial loss (gain)	176.4	154.4
Prior service credit	0	0
Total	176.4	154.4
Pension plans with accumulated benefit obligations in excess of plan assets [Abstract]
Projected benefit obligation	309.6	281.8
Accumulated benefit obligation	307.2	280.3
Fair value of the plan assets	200.6	186.6
Components of net periodic benefit costs [Abstract]
Service cost	0.6	1.4	1.9
Interest cost	13.5	13.9	13.7
Expected return on plan assets	(16.1)	(15.7)	(15.2)
Amortization of [Abstract]
Unrecognized net loss (gain)	5.0	7.0	7.7
Unrecognized prior service cost (credit)	0	0	0.4
Adjustment for settlement/curtailment	0	0	1.6
Net periodic benefit cost (income)	3.0	6.6	10.1
Other changes in plan assets and benefit obligation recognized in other comprehensive loss (income) [Abstract]
Net actuarial loss (gain)	27.0	45.7	(3.7)
Prior service (credits) costs	0	0	(1.6)
Reversal of amortization items [Abstract]
Net actuarial loss (gain)	(5.0)	(7.0)	(7.7)
Prior service costs (credit)	0	0	(0.4)
Total recognized in other comprehensive loss (income)	22.0	38.7	(13.4)
Total recognized in net periodic benefit costs and other comprehensive income	25.0	45.3	(3.3)
Estimated net actuarial loss that will be amortized	6.3
Estimated future benefit payments [Abstract]
Anticipated contributions for 2014 fiscal year	8.0
2014	14.5
2015	15.1
2016	15.5
2017	16.2
2018	17.5
2019-2023	92.5
Postretirement Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit plan curtailment charge		0.3	2.1
Future costs cap (in hundredths)	200.00%
Change in benefit obligation [Roll Forward]
Benefit obligation at beginning of year	7.2	6.6
Service cost	0.1	0	0
Interest cost	0.3	0.4	0.4
Actuarial loss	0.1	0.5
Benefits paid	(0.2)	(0.5)
Settlement Curtailment adjustment	0	0.2
Currency translation adjustment	0	0
Benefit obligation at end of year	7.5	7.2	6.6
Change in plan assets [Roll Forward]
Fair value of plan assets at beginning of year	0	0
Actual return on plan assets	0	0
Benefits paid	(0.2)	(0.5)
Employer contributions	0.2	0.5
Fair value of plan assets at end of year	0	0	0
Funded status at end of year	(7.5)	(7.2)
Amounts recognized in the consolidated balance sheet consist of [Abstract]
Current liability	(0.8)	(0.8)
Noncurrent liability	(6.7)	(6.4)
Total liability	(7.5)	(7.2)
Amounts recognized in accumulated other comprehensive loss consist of [Abstract]
Net actuarial loss (gain)	(0.3)	(0.4)
Prior service credit	(1.5)	(3.0)
Total	(1.8)	(3.4)
Components of net periodic benefit costs [Abstract]
Service cost	0.1	0	0
Interest cost	0.3	0.4	0.4
Expected return on plan assets	0	0	0
Amortization of [Abstract]
Unrecognized net loss (gain)	0	0	(0.1)
Unrecognized prior service cost (credit)	(1.5)	(1.7)	(1.8)
Adjustment for settlement/curtailment	0	(0.3)	(2.1)
Net periodic benefit cost (income)	(1.1)	(1.6)	(3.6)
Other changes in plan assets and benefit obligation recognized in other comprehensive loss (income) [Abstract]
Net actuarial loss (gain)	0	0.7	(2.2)
Prior service (credits) costs	0	0.3	2.3
Reversal of amortization items [Abstract]
Net actuarial loss (gain)	0.1	0	0.1
Prior service costs (credit)	1.5	1.7	1.8
Total recognized in other comprehensive loss (income)	1.6	2.7	2.0
Total recognized in net periodic benefit costs and other comprehensive income	0.5	1.1	(1.6)
Estimated prior service credit that will be amortized	1.2
Assumed healthcare cost trend rates [Abstract]
Healthcare costs trend rate assumed for next year (pre-65) (in hundredths)	7.50%	7.50%
Healthcare costs trend rate assumed for next year (post-65) (in hundredths)	7.50%	7.50%
Ultimate trend rate (in hundredths)	5.00%	5.00%
Year the rate reaches the ultimate trend rate	2019	2017
Effect of one percentage point change in assumed health care cost trend rates [Abstract]
Effect on total of service and interest cost on one percentage point increase	0.1
Effect on total of service and interest cost on one percentage point decrease	0.1
Effect on postretirement benefit obligation for one percentage point increase	0.2
Effect on postretirement benefit obligation for one percentage point decrease	(0.2)
U.S. Pension Plans [Member]
Change in plan assets [Roll Forward]
Fair value of plan assets at beginning of year	186.6
Employer contributions	9.2	11.5	17.9
Fair value of plan assets at end of year	$ 200.6	$ 186.6
Weighted-average assumptions used in calculating benefit obligation [Abstract]
Discount rate (in hundredths)	4.40%	4.90%
Weighted-average assumptions used in calculating costs under the plan [Abstract]
Discount rate (in hundredths)	4.90%	5.80%	5.90%
Expected return on plan assets (in hundredths)	8.00%	8.00%	8.10%
Defined Benefit Plan, Information about Plan Assets [Abstract]
Target allocation (in hundredths)	100.00%	100.00%
Plan assets (in hundredths)	100.00%	100.00%
Modine common stock included in the plan assets (in shares)	0	0
Expected return on plan assets for next fiscal year (in hundredths)	8.00%
U.S. Pension Plans [Member] | Equity Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Target allocation (in hundredths)	55.00%	55.00%
Plan assets (in hundredths)	57.00%	56.00%
U.S. Pension Plans [Member] | Debt Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Target allocation (in hundredths)	38.00%	38.00%
Plan assets (in hundredths)	37.00%	37.00%
U.S. Pension Plans [Member] | Alternative Assets [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Target allocation (in hundredths)	5.00%	5.00%
Plan assets (in hundredths)	5.00%	5.00%
U.S. Pension Plans [Member] | Cash [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Target allocation (in hundredths)	2.00%	2.00%
Plan assets (in hundredths)	1.00%	2.00%
Foreign Pension Plans [Member]
Weighted-average assumptions used in calculating benefit obligation [Abstract]
Discount rate (in hundredths)	3.50%	5.00%
Weighted-average assumptions used in calculating costs under the plan [Abstract]
Discount rate (in hundredths)	5.00%	5.80%	5.00%
U.S. Postretirement Plans [Member]
Weighted-average assumptions used in calculating benefit obligation [Abstract]
Discount rate (in hundredths)	3.70%	4.40%
Weighted-average assumptions used in calculating costs under the plan [Abstract]
Discount rate (in hundredths)	4.40%	5.40%	5.40%