Contingencies (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Government Assets Guaranteed Under Contract [Member]
Guarantor Obligations [Line Items]
Assets guaranteed under contract	$ 12,319
Percentage of assets expected to be sold	100.00%
Industrial Assets Guaranteed Under Contract [Member]
Guarantor Obligations [Line Items]
Assets guaranteed under contract	$ 11,756	$ 3,813
Percentage of assets expected to be sold	100.00%	100.00%
Agricultural Assets Guaranteed Under Contract [Member]
Guarantor Obligations [Line Items]
Assets guaranteed under contract	$ 6,873	$ 11,415
Percentage of assets expected to be sold	100.00%	100.00%