Pensions (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer	$ 2.1	$ 2.8	$ 5.9	$ 6.2
Pension [Member]
Pension plans [Abstract]
Service cost	0.1	0.2	0.4	0.5
Interest cost	3.3	3.2	9.8	9.7
Expected return on plan assets	(4.2)	(3.9)	(12.6)	(11.8)
Amortization of unrecognized net loss	1.4	1.6	4.2	4.7
Net periodic benefit cost	$ 0.6	$ 1.1	$ 1.8	$ 3.1