Accumulated Other Comprehensive Income (Loss) Reclassification Adjustments (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Document Period End Date				Jun. 30, 2017
Interest expense		$ (32.2)	$ (24.3)	$ (63.0)	$ (35.8)
Total reclassifications for the period		0.8	1.0	(3.4)	1.8
Interest Rate Hedges | Reclassification out of Accumulated Other Comprehensive Income [Member]
Interest expense		(0.1)	0.0	(0.4)	(0.1)
Net actuarial loss amortization | Reclassification out of Accumulated Other Comprehensive Income [Member]
Net periodic benefit cost	[1]	0.9	1.0	(3.0)	1.9
Net actuarial loss amortization, tax		(0.5)	(0.5)	1.0	(1.0)
Pension and Other Post-retirement Benefits
Total reclassifications for the period		$ 0.9	$ 1.0	$ (3.0)	$ 1.9

[1] Pension and other post-retirement benefits AOCI components are included in the computation of net periodic benefit cost (refer to note 14).