Allowance for Credit Losses (Activity in Allowance for Doubtful Accounts) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance		$ 10	$ 22	$ 22
Reversal of provision	3	(7)	(22)	(12)
Ending Balance	3	3		10
Accounts Receivable Allowance for Doubtful Accounts [Member] | Operating Leases [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance		10	22	22
Reversal of provision		(7)		(12)
Ending Balance	3	3		10
Accounts Receivable Allowance for Doubtful Accounts [Member] | Finance Leases [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance
Reversal of provision
Ending Balance
Valuation Adjustments on Financing Receivables [Member] | Finance Leases [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance
Reversal of provision
Ending Balance