Accounts Receivable, Net of Allowance (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Change in Accounting Estimate [Line Items]
Provisions for doubtful accounts	$ 1.4	$ 0.3	$ 2.2	$ 1.1
Financing Receivable [Member]
Change in Accounting Estimate [Line Items]
Increase in cash collections from non-recourse financing arrangement			29.0
Financing Receivable [Member] | Interest Expense [Member]
Change in Accounting Estimate [Line Items]
Non-recourse financing arrangement, discount charge			$ 1.1
Uncollectible Receivables [Member]
Change in Accounting Estimate [Line Items]
Change in estimate, provision for doubtful accounts				$ 0.5