Pension and Post-retirement and Other Benefit Plans - Pre-Tax Changes in Projected Benefit Obligations and Plan Assets Recognized in Other Comprehensive Income (Details) - USD ($) $ in Millions		12 Months Ended
	Aug. 31, 2015	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Prior service cost (credit)	$ 1.2
Pensions
Defined Benefit Plan Disclosure [Line Items]
Actuarial (gain) loss		$ 15.6
Prior service cost (credit)		0.0
Amortization of net actuarial gain (loss)		(4.8)
Amortization of prior service credit (cost)		0.0
Total (income) loss recognized in other comprehensive income		(10.8)
Total recognized in net periodic benefit cost and other comprehensive income		11.7
Other post-retirement benefits
Defined Benefit Plan Disclosure [Line Items]
Actuarial (gain) loss		(0.5)
Prior service cost (credit)		(0.1)
Amortization of net actuarial gain (loss)		0.0
Amortization of prior service credit (cost)		2.5
Total (income) loss recognized in other comprehensive income		(1.9)
Total recognized in net periodic benefit cost and other comprehensive income		$ (0.4)