Segment Information (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Mar. 31, 2021
Segment Information [Abstract]
Net sales		$ 478.9	$ 461.4	$ 973.5	$ 809.2
Gross profit		$ 66.3	$ 80.8	$ 139.5	$ 126.9
Gross profit (% of sales)		13.80%	17.50%	14.30%	15.70%
Operating income (loss)		$ 10.5	$ 28.5	$ 19.2	$ 25.3
Total assets		1,322.0		1,322.0		$ 1,276.7
BHVAC [Member]
Segment Information [Abstract]
Net sales		77.5	68.5	144.1	122.6
CIS [Member]
Segment Information [Abstract]
Net sales		153.5	128.2	307.6	244.7
HDE [Member]
Segment Information [Abstract]
Net sales		195.8	165.6	397.6	289.1
Automotive [Member]
Segment Information [Abstract]
Net sales		65.4	109.9	151.6	172.0
Segment Total [Member]
Segment Information [Abstract]
Net sales		492.2	472.2	1,000.9	828.4
Operating Segments [Member]
Segment Information [Abstract]
Net sales		478.9	461.4	973.5	809.2
Gross profit		$ 65.4	$ 81.2	$ 138.2	$ 127.3
Gross profit (% of sales)		13.30%	17.20%	13.80%	15.40%
Operating income (loss)		$ 16.0	$ 40.0	$ 42.3	$ 40.8
Operating Segments [Member] | BHVAC [Member]
Segment Information [Abstract]
Net sales		77.4	68.2	142.8	122.1
Gross profit		$ 21.6	$ 23.3	$ 37.8	$ 39.1
Gross profit (% of sales)		27.80%	34.10%	26.20%	31.90%
Operating income (loss)		$ 10.0	$ 13.5	$ 15.7	$ 20.7
Total assets		204.2		204.2		181.1
Operating Segments [Member] | CIS [Member]
Segment Information [Abstract]
Net sales		151.2	126.9	303.4	241.7
Gross profit		$ 18.3	$ 17.7	$ 39.1	$ 31.9
Gross profit (% of sales)		11.90%	13.80%	12.70%	13.00%
Operating income (loss)		$ 5.8	$ 5.2	$ 13.3	$ 5.1
Total assets		551.5		551.5		540.1
Operating Segments [Member] | HDE [Member]
Segment Information [Abstract]
Net sales		185.8	157.6	377.7	275.9
Gross profit		$ 18.3	$ 23.6	$ 40.9	$ 34.9
Gross profit (% of sales)		9.40%	14.20%	10.30%	12.10%
Operating income (loss)		$ 5.8	$ 13.3	$ 14.7	$ 10.8
Total assets		451.0		451.0		438.7
Operating Segments [Member] | Automotive [Member]
Segment Information [Abstract]
Net sales		64.5	108.7	149.6	169.5
Gross profit		$ 7.2	$ 16.6	$ 20.4	$ 21.4
Gross profit (% of sales)		11.00%	15.20%	13.40%	12.50%
Operating income (loss)		$ (5.6)	$ 8.0	$ (1.4)	$ 4.2
Total assets		117.6		117.6		124.2
Inter-segment Sales [Member]
Segment Information [Abstract]
Net sales		13.3	10.8	27.4	19.2
Inter-segment Sales [Member] | BHVAC [Member]
Segment Information [Abstract]
Net sales		0.1	0.3	1.3	0.5
Inter-segment Sales [Member] | CIS [Member]
Segment Information [Abstract]
Net sales		2.3	1.3	4.2	3.0
Inter-segment Sales [Member] | HDE [Member]
Segment Information [Abstract]
Net sales		10.0	8.0	19.9	13.2
Inter-segment Sales [Member] | Automotive [Member]
Segment Information [Abstract]
Net sales		0.9	1.2	2.0	2.5
Corporate and Eliminations [Member]
Segment Information [Abstract]
Net sales		(13.3)	(10.8)	(27.4)	(19.2)
Gross profit		$ 0.9	$ (0.4)	$ 1.3	$ (0.4)
Gross profit (% of sales)		0.00%	0.00%	0.00%	0.00%
Operating income (loss)		$ (5.5)	$ (11.5)	$ (23.1)	$ (15.5)
Total assets	[1]	(2.3)		(2.3)		(7.4)
Corporate [Member]
Segment Information [Abstract]
Total assets		$ 23.2		$ 23.2		$ 17.5

[1] At September 30, 2021 and March 31, 2021, Corporate assets totaled $23.2 million and $17.5 million, respectively and were more than offset by eliminations for intercompany balances, including accounts receivable.