Derivative Instruments (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Derivative, Cost of Hedge Net of Cash Received	$ 4.2	$ 4.6
Other Current Liabilities [Member]
Derivative [Line Items]
Derivative, Cost of Hedge Net of Cash Received	2.0	2.0
Other Noncurrent Liabilities [Member]
Derivative [Line Items]
Derivative, Cost of Hedge Net of Cash Received	$ 2.2	$ 2.6