Leases (Details 1) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Credit risk profile by creditworthiness category of direct financing lease receivables
Credit risk profile by creditworthiness category of direct financing lease receivables, Total	$ 449,310	$ 434,690
Very low risk to low risk [Member]
Credit risk profile by creditworthiness category of direct financing lease receivables
Credit risk profile by creditworthiness category of direct financing lease receivables, Total	198,496	203,556
Moderate [Member]
Credit risk profile by creditworthiness category of direct financing lease receivables
Credit risk profile by creditworthiness category of direct financing lease receivables, Total	158,790	164,761
Moderately high to high risk [Member]
Credit risk profile by creditworthiness category of direct financing lease receivables
Credit risk profile by creditworthiness category of direct financing lease receivables, Total	$ 92,024	$ 66,373