Collateralized Receivables and Transfers of Financial Assets Collateralized Receivables and Transfers of Financial Assets, Allowance for Collateralized Receivables (Details) - Collateralized Receivables [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	$ (607)	$ (672)
Allowance for Loan and Lease Losses, Write-offs	1,024	617
Provision for Loan and Lease Losses	(1,353)	(552)
Total activity	(329)	65
Ending balance	$ (936)	$ (607)