Leases (Details 1) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Credit risk profile by creditworthiness category of direct financing lease receivables
Credit risk profile by creditworthiness category of direct financing lease receivables, Total	$ 450,642	$ 478,735
Very low risk to low risk
Credit risk profile by creditworthiness category of direct financing lease receivables
Credit risk profile by creditworthiness category of direct financing lease receivables, Total	192,853	203,388
Moderate
Credit risk profile by creditworthiness category of direct financing lease receivables
Credit risk profile by creditworthiness category of direct financing lease receivables, Total	194,234	197,484
Moderately high to high risk
Credit risk profile by creditworthiness category of direct financing lease receivables
Credit risk profile by creditworthiness category of direct financing lease receivables, Total	$ 63,555	$ 77,863