Allowance for Credit Losses - Summary of Allowance for Credit Losses (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Allowance for credit losses and recorded investment in financing receivables
Balance at January 1	$ 4.4	$ 4.6
Write-offs	0.1	0.0
Balance at June 30	4.3	4.6
Finance Leases Financing Receivable [Member]
Allowance for credit losses and recorded investment in financing receivables
Balance at January 1	0.3	0.5
Write-offs	0.1	0.0
Balance at June 30	0.2	0.5
Notes Receivable [Member]
Allowance for credit losses and recorded investment in financing receivables
Balance at January 1	4.1	4.1
Write-offs	0.0	0.0
Balance at June 30	$ 4.1	$ 4.1