Direct Financing Lease Receivables (Details 1) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Financing Receivable, Recorded Investment [Line Items]
Credit risk profile by creditworthiness category of direct financing lease receivables, Total	$ 412,195	$ 428,142
Very low risk to low risk [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit risk profile by creditworthiness category of direct financing lease receivables, Total	172,034	193,123
Moderate risk [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit risk profile by creditworthiness category of direct financing lease receivables, Total	175,056	177,400
Moderately high to High risk [Member]
Financing Receivable, Recorded Investment [Line Items]
Credit risk profile by creditworthiness category of direct financing lease receivables, Total	$ 65,105	$ 57,619