Derivative Instruments and Hedging Activities (Narrative) (Details) - USD ($) $ in Millions		3 Months Ended	12 Months Ended
	Feb. 01, 2017	Dec. 31, 2017	Dec. 31, 2017
Derivative [Line Items]
Unrealized Gain (Loss) on Price Risk Cash Flow Derivatives, before Tax			$ (1.3)
Derivative, Maturity Date		Jan. 01, 2021
Acquisition, Cash Consideration Paid Canadian Dollars	$ 1,125.0
Derivative Instruments, Gain (Loss) Reclassification from Accumulated OCI to Income, Estimated Net Amount to be Transferred			$ 0.1