Segment Information (Details) - USD ($) $ in Millions	3 Months Ended				9 Months Ended
	Dec. 31, 2020		Sep. 30, 2020	Dec. 31, 2019	Dec. 31, 2020		Dec. 31, 2019	Mar. 31, 2020
Segment Reporting Information [Abstract]
Net sales	$ 484.3			$ 473.4	$ 1,293.5		$ 1,502.6
Gross profit	$ 82.7			$ 73.5	$ 209.6		$ 232.6
Gross profit (% of sales)	17.10%			15.50%	16.20%		15.50%
Operating (loss) income	$ (108.7)			$ 8.2	$ (83.4)		$ 32.3
Total assets	1,306.7				1,306.7			$ 1,536.1
Impairment charges	134.4			0.0	134.4		0.0
Change in deferred tax asset valuation allowance	116.5		$ 6.6		109.9
CIS [Member]
Segment Reporting Information [Abstract]
Net sales	129.0			147.5	385.6		473.0
BHVAC [Member]
Segment Reporting Information [Abstract]
Net sales	68.7			64.9	178.2		169.9
HDE [Member]
Segment Reporting Information [Abstract]
Net sales	185.6			164.9	474.7		568.5
Automotive [Member]
Segment Reporting Information [Abstract]
Net sales	113.9			110.5	285.9		339.8
Impairment charges	(1.7)
Total Segments [Member]
Segment Reporting Information [Abstract]
Net sales	497.2			487.8	1,324.4		1,551.2
Operating Segments [Member]
Segment Reporting Information [Abstract]
Net sales	484.3			473.4	1,293.5		1,502.6
Gross profit	$ 82.7			$ 74.8	$ 210.0		$ 233.8
Gross profit (% of sales)	16.60%			15.30%	15.90%		15.10%
Operating (loss) income	$ (98.0)			$ 26.2	$ (57.2)		$ 82.6
Operating Segments [Member] | CIS [Member]
Segment Reporting Information [Abstract]
Net sales	128.3			146.3	382.8		469.9
Gross profit	$ 12.6			$ 22.7	$ 47.4		$ 69.9
Gross profit (% of sales)	9.80%			15.40%	12.30%		14.80%
Operating (loss) income	$ (1.7)			$ 8.3	$ 3.9		$ 25.8
Total assets	601.8				601.8			617.7
Operating Segments [Member] | BHVAC [Member]
Segment Reporting Information [Abstract]
Net sales	68.7			64.3	178.0		168.5
Gross profit	$ 25.7			$ 23.1	$ 61.9		$ 54.5
Gross profit (% of sales)	37.30%			35.50%	34.70%		32.10%
Operating (loss) income	$ 15.8			$ 13.5	$ 36.0		$ 27.6
Total assets	106.7				106.7			102.3
Operating Segments [Member] | HDE [Member]
Segment Reporting Information [Abstract]
Net sales	173.7			152.8	449.6		526.4
Gross profit	$ 26.0			$ 16.8	$ 60.9		$ 71.7
Gross profit (% of sales)	14.00%			10.20%	12.80%		12.60%
Operating (loss) income	$ 12.8			$ 2.8	$ 23.6		$ 27.2
Total assets	428.3				428.3			417.4
Operating Segments [Member] | Automotive [Member]
Segment Reporting Information [Abstract]
Net sales	113.6			110.0	283.1		337.8
Gross profit	$ 18.4			$ 12.2	$ 39.8		$ 37.7
Gross profit (% of sales)	16.10%			11.00%	13.90%		11.10%
Operating (loss) income	$ (124.9)			$ 1.6	$ (120.7)		$ 2.0
Total assets	161.2	[1]			161.2	[1]		272.5
Corporate and Eliminations [Member]
Segment Reporting Information [Abstract]
Net sales	(12.9)			(14.4)	(30.9)		(48.6)
Gross profit	$ 0.0			$ (1.3)	$ (0.4)		$ (1.2)
Gross profit (% of sales)	0.00%			0.00%	0.00%		0.00%
Operating (loss) income	$ (10.7)			$ (18.0)	$ (26.2)		$ (50.3)
Total assets	8.7	[2]			8.7	[2]		$ 126.2
Inter-segment Sales [Member]
Segment Reporting Information [Abstract]
Net sales	12.9			14.4	30.9		48.6
Inter-segment Sales [Member] | CIS [Member]
Segment Reporting Information [Abstract]
Net sales	0.7			1.2	2.8		3.1
Inter-segment Sales [Member] | BHVAC [Member]
Segment Reporting Information [Abstract]
Net sales	0.0			0.6	0.2		1.4
Inter-segment Sales [Member] | HDE [Member]
Segment Reporting Information [Abstract]
Net sales	11.9			12.1	25.1		42.1
Inter-segment Sales [Member] | Automotive [Member]
Segment Reporting Information [Abstract]
Net sales	$ 0.3			$ 0.5	$ 2.8		$ 2.0

[1] During the third quarter of fiscal 2021, the Company recorded impairment charges totaling $134.4 million within the Automotive segment, primarily related to the property, plant and equipment of the liquid-cooled automotive business, the sale of which is pending.  See Note 2 for additional information.

[2] During the nine months ended December 31, 2020, the Company recorded income tax charges totaling $109.9 million to increase the valuation allowance on deferred tax assets in the U.S, which are recorded at Corporate.  See Note 9 for additional information.