Hedging Activities and Fair Value Measurements, Derivative Instruments included in the Condensed Consolidated Statements of Comprehensive (Loss) Income (Details) - Interest Rate Swap Contracts [Member] - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Gains and Losses on Derivatives Designated as Cash Flow Hedges [Abstract]
Gain (loss) recognized in AOCI on derivatives	[1]	$ 3.1	$ (6.1)	$ 13.4	$ (6.3)
Loss reclassified from AOCI into income	[1]	$ (3.1)	$ (4.7)	$ (7.9)	$ (9.8)

[1] Losses on derivatives reclassified from accumulated other comprehensive income ("AOCI") into income were included in "Interest expense" in the Condensed Consolidated Statements of Operations, the same income statement line item as the earnings effect of the hedged item.