Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions		12 Months Ended
		Mar. 31, 2020		Mar. 31, 2019
Other comprehensive loss [Abstract]
Beginning balance		$ 533.9
Other comprehensive income (loss) before reclassifications		(59.4)		$ (44.7)
Reclassifications for amortization of unrecognized net loss	[1]	5.8		5.4
Reclassifications for realized losses - net	[2]	0.5		0.2
Reclassifications for foreign currency translation (gains) losses		(0.6)	[3]	0.8	[4]
Income taxes		8.8		0.2
Total other comprehensive income (loss)		(44.9)		(38.1)
Ending balance		487.9		533.9
Nikkei Heat Exchanger Company, Ltd [Member]
Other comprehensive loss [Abstract]
Gain (loss) on write-off of accumulated foreign currency translation		0.6
AIAC Air Conditioning South Africa Pty Ltd [Member]
Other comprehensive loss [Abstract]
Gain (loss) on write-off of accumulated foreign currency translation				(0.8)
Accumulated Other Comprehensive Loss [Member]
Other comprehensive loss [Abstract]
Beginning balance		(178.4)		(140.3)
Ending balance		(223.3)		(178.4)
Foreign Currency Translation [Member]
Other comprehensive loss [Abstract]
Beginning balance		(42.6)		(5.5)
Other comprehensive income (loss) before reclassifications		(18.2)		(37.9)
Reclassifications for amortization of unrecognized net loss	[1]	0.0		0.0
Reclassifications for realized losses - net	[2]	0.0		0.0
Reclassifications for foreign currency translation (gains) losses		(0.6)	[3]	0.8	[4]
Income taxes		0.0		0.0
Total other comprehensive income (loss)		(18.8)		(37.1)
Ending balance		(61.4)		(42.6)
Defined Benefit Plans [Member]
Other comprehensive loss [Abstract]
Beginning balance		(136.3)		(134.9)
Other comprehensive income (loss) before reclassifications		(38.7)		(7.1)
Reclassifications for amortization of unrecognized net loss	[1]	5.8		5.4
Reclassifications for realized losses - net	[2]	0.0		0.0
Reclassifications for foreign currency translation (gains) losses		0.0	[3]	0.0	[4]
Income taxes		8.3		0.3
Total other comprehensive income (loss)		(24.6)		(1.4)
Ending balance		(160.9)		(136.3)
Cash Flow Hedges [Member]
Other comprehensive loss [Abstract]
Beginning balance		0.5		0.1
Other comprehensive income (loss) before reclassifications		(2.5)		0.3
Reclassifications for amortization of unrecognized net loss	[1]	0.0		0.0
Reclassifications for realized losses - net	[2]	0.5		0.2
Reclassifications for foreign currency translation (gains) losses		0.0	[3]	0.0	[4]
Income taxes		0.5		(0.1)
Total other comprehensive income (loss)		(1.5)		0.4
Ending balance		$ (1.0)		$ 0.5

[1] Amounts are included in the calculation of net periodic benefit cost for the Company’s defined benefit plans, which include pension and other postretirement plans.  See Note 18 for additional information about the Company’s pension plans.

[2] Amounts represent net gains and losses associated with cash flow hedges that were reclassified to net earnings.  See Note 19 for additional information regarding derivative instruments.

[3] As a result of the sale of its investment in NEX during fiscal 2020, the Company wrote off $0.6 million of accumulated foreign currency translation gains.

[4] As a result of the sale of a business in South Africa during fiscal 2019, the Company wrote off $0.8 million of accumulated foreign currency translation losses.