Allowance for Credit Losses - Summary of Allowance for Credit Losses (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Allowance for credit losses and recorded investment in financing receivables
January Balance	$ 4.5	$ 4.5
Provision for credit losses	0.3	0.1
Write-offs	(0.1)	(0.2)
June Balance	4.7	4.4
Finance Leases Financing Receivable [Member]
Allowance for credit losses and recorded investment in financing receivables
January Balance	0.4	0.4
Provision for credit losses	0.3	0.1
Write-offs	(0.1)	(0.2)
June Balance	0.6	0.3
Notes Receivable [Member]
Allowance for credit losses and recorded investment in financing receivables
January Balance	4.1	4.1
Provision for credit losses	0.0	0.0
Write-offs	0.0	0.0
June Balance	$ 4.1	$ 4.1