Allowance for Credit Losses - Summary of Allowance for Credit Losses (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Allowance for credit losses and recorded investment in financing receivables
Financing Receivable, Allowance for Credit Losses, Beginning balance	$ 2,257	$ 848
Financing Receivable, Allowance for Credit Losses, Provisions	261	1,919
Financing Receivable, Allowance for Credit Losses, Recoveries	48	5,565
Financing Receivable, Allowance for Credit Losses, Charge-offs	0	(6,321)
Financing Receivable, Allowance for Credit Losses, Ending balance	2,566	2,011
Allowance resulting from individual impairment evaluation	2,566	2,011
Allowance resulting from collective impairment evaluation	0	0
Recorded investment in financing receivables
Balance individually evaluated for impairment	113,318	118,236
Balance collectively evaluated for impairment	0	0
Finance Leases Financing Receivable [Member]
Allowance for credit losses and recorded investment in financing receivables
Financing Receivable, Allowance for Credit Losses, Beginning balance	210	378
Financing Receivable, Allowance for Credit Losses, Provisions	261	47
Financing Receivable, Allowance for Credit Losses, Recoveries	48	111
Financing Receivable, Allowance for Credit Losses, Charge-offs	0	(365)
Financing Receivable, Allowance for Credit Losses, Ending balance	519	171
Allowance resulting from individual impairment evaluation	519	171
Allowance resulting from collective impairment evaluation	0	0
Recorded investment in financing receivables
Balance individually evaluated for impairment	100,436	105,468
Balance collectively evaluated for impairment	0	0
Notes Receivable [Member]
Allowance for credit losses and recorded investment in financing receivables
Financing Receivable, Allowance for Credit Losses, Beginning balance	2,047	470
Financing Receivable, Allowance for Credit Losses, Provisions	0	1,872
Financing Receivable, Allowance for Credit Losses, Recoveries	0	5,454
Financing Receivable, Allowance for Credit Losses, Charge-offs	0	(5,956)
Financing Receivable, Allowance for Credit Losses, Ending balance	2,047	1,840
Allowance resulting from individual impairment evaluation	2,047	1,840
Allowance resulting from collective impairment evaluation	0	0
Recorded investment in financing receivables
Balance individually evaluated for impairment	12,882	12,768
Balance collectively evaluated for impairment	$ 0	$ 0