General (Details) - USD ($) $ in Millions	3 Months Ended				9 Months Ended		12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Sale of Business [Abstract]
Gain (loss) on sale of assets	$ 0.8		$ 0.0		$ 0.8	$ (1.7)
Leases [Abstract]
Right-of-use assets	64.3				64.3		$ 61.3
Operating lease liabilities, Other current liabilities	11.1				11.1
Operating lease liabilities, Other noncurrent liabilities	52.9				52.9
Operating leases, right-of-use liabilities	64.0				64.0
New Accounting Guidance Adopted [Abstract]
Retained earnings	476.6				476.6		472.1
Vehicular Thermal Solutions [Member]
Sale of Business [Abstract]
Gain (loss) on sale of assets	0.8
Selling price	$ 6.0				6.0
Real Estate Leases [Member]
Leases [Abstract]
Right-of-use assets							61.3
Operating lease liabilities, Other current liabilities							12.4
Operating lease liabilities, Other noncurrent liabilities							48.9
Build to Suit Arrangements [Member]
Leases [Abstract]
Right-of-use assets							5.2
Operating leases, right-of-use liabilities							5.2
AIAC Air Conditioning South Africa (Pty) Ltd [Member]
Sale of Business [Abstract]
Selling price				$ 0.5
Gain (loss) on sale of business				(1.7)
Gain (loss) on write-off of accumulated foreign currency translation				$ (0.8)
AIAC Air Conditioning South Africa (Pty) Ltd [Member] | Maximum [Member]
Sale of Business [Abstract]
Annual net sales attributable to disposed business							$ 2.0
Nikkei Heat Exchanger Company, Ltd [Member]
Sale of Business [Abstract]
Ownership percentage		50.00%
Selling price		$ 3.8
Gain (loss) on sale of business		0.1			$ 0.1
Gain (loss) on write-off of accumulated foreign currency translation		$ 0.6
ASU 2014-09 [Member]
New Accounting Guidance Adopted [Abstract]
Retained earnings								$ 0.7
ASU 2016-16 [Member]
New Accounting Guidance Adopted [Abstract]
Retained earnings								$ (8.3)