Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Other comprehensive income (Loss) [Abstract]
Beginning balance				$ 490.1
Other comprehensive income (loss) before reclassifications		$ (6.8)	$ 11.3	(31.0)	$ 27.8
Reclassifications for amortization of unrecognized net loss	[1]	1.3	1.3	2.6	2.6
Reclassifications for foreign currency translation losses	[2]	0.8		0.8
Income taxes		(0.1)	(0.4)	(0.5)	(0.9)
Total other comprehensive income (loss)		(4.8)	12.2	(28.1)	29.5
Ending balance		516.6		516.6
AIAC Air Conditioning South Africa Pty Ltd Member [Member]
Other comprehensive income (Loss) [Abstract]
Loss on write-off of accumulated foreign currency translation		(0.8)
Accumulated Other Comprehensive Loss [Member]
Other comprehensive income (Loss) [Abstract]
Beginning balance		(163.6)	(164.5)	(140.3)	(181.8)
Ending balance		(168.4)	(152.3)	(168.4)	(152.3)
Foreign Currency Translation [Member]
Other comprehensive income (Loss) [Abstract]
Beginning balance		(30.2)	(30.3)	(5.5)	(46.8)
Other comprehensive income (loss) before reclassifications		(6.1)	11.3	(30.8)	27.8
Reclassifications for amortization of unrecognized net loss	[1]	0.0	0.0	0.0	0.0
Reclassifications for foreign currency translation losses	[2]	0.8		0.8
Income taxes		0.0	0.0	0.0	0.0
Total other comprehensive income (loss)		(5.3)	11.3	(30.0)	27.8
Ending balance		(35.5)	(19.0)	(35.5)	(19.0)
Defined Benefit Plans [Member]
Other comprehensive income (Loss) [Abstract]
Beginning balance		(133.9)	(134.2)	(134.9)	(135.0)
Other comprehensive income (loss) before reclassifications		0.0	0.0	0.0	0.0
Reclassifications for amortization of unrecognized net loss	[1]	1.3	1.3	2.6	2.6
Reclassifications for foreign currency translation losses	[2]	0.0		0.0
Income taxes		(0.3)	(0.4)	(0.6)	(0.9)
Total other comprehensive income (loss)		1.0	0.9	2.0	1.7
Ending balance		(132.9)	$ (133.3)	(132.9)	$ (133.3)
Cash Flow Hedges [Member]
Other comprehensive income (Loss) [Abstract]
Beginning balance		0.5		0.1
Other comprehensive income (loss) before reclassifications		(0.7)		(0.2)
Reclassifications for amortization of unrecognized net loss	[1]	0.0		0.0
Reclassifications for foreign currency translation losses	[2]	0.0		0.0
Income taxes		0.2		0.1
Total other comprehensive income (loss)		(0.5)		(0.1)
Ending balance		$ 0.0		$ 0.0

[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 4 for additional information about the Company's pension plans.

[2] As a result of the sale of a business in South Africa during the second quarter of fiscal 2019, the Company wrote-off $0.8 million of accumulated foreign currency translation losses. See Note 1 for additional information about this transaction.