Accounts Receivable, Net of Allowance (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Schedule of Accounts Receivable, Net of Allowance [Line Items]
Provisions for doubtful accounts	$ 0.2	$ 1.3	$ 0.7	$ 1.7
Interest Expense [Member] | Financing Receivable [Member]
Schedule of Accounts Receivable, Net of Allowance [Line Items]
Non-recourse financing arrangement, discount charge	$ 1.7	$ 0.5	$ 2.6	$ 0.9