Significant Accounting Policies, Cumulative Effects on Consolidated Balance Sheet Resulting in Adoption of New Accounting Guidance (Details) - USD ($) $ in Millions	Mar. 31, 2019	Mar. 31, 2018
ASSETS [Abstract]
Inventories	$ 200.7	$ 191.3
Other current assets	65.8	70.1
Deferred income taxes	97.1	96.9
LIABILITIES AND SHAREHOLDERS' EQUITY [Abstract]
Deferred income taxes	8.2	9.9
Retained earnings	$ 472.1	394.9
Adjustments Due to New Accounting [Member]
ASSETS [Abstract]
Inventories		189.3
Other current assets		64.8
Deferred income taxes		96.7
LIABILITIES AND SHAREHOLDERS' EQUITY [Abstract]
Deferred income taxes		10.0
Retained earnings		387.3
ASU 2014-09 [Member]
ASSETS [Abstract]
Inventories		(2.0)
Other current assets		3.0
Deferred income taxes		(0.2)
LIABILITIES AND SHAREHOLDERS' EQUITY [Abstract]
Deferred income taxes		0.1
Retained earnings		0.7
ASU 2016-16 [Member]
ASSETS [Abstract]
Inventories		0.0
Other current assets		(8.3)
Deferred income taxes		0.0
LIABILITIES AND SHAREHOLDERS' EQUITY [Abstract]
Deferred income taxes		0.0
Retained earnings		$ (8.3)