Goodwill and Other Intangible Assets Goodwill and Other Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Goodwill [Roll Forward]
Balance as of January 1, 2017			$ 63,934
Acquisitions			1,171
Impairments	$ 0	$ 0	(42,000)	$ 0
Balance as of September 30, 2017	23,105	$ 63,934	23,105	$ 63,934
Grain
Goodwill [Roll Forward]
Balance as of January 1, 2017			0
Acquisitions			1,171
Impairments			0
Balance as of September 30, 2017	1,171		1,171
Plant Nutrient
Goodwill [Roll Forward]
Balance as of January 1, 2017			59,767
Acquisitions			0
Impairments			(42,000)
Balance as of September 30, 2017	17,767		17,767
Rail
Goodwill [Roll Forward]
Balance as of January 1, 2017			4,167
Acquisitions			0
Impairments			0
Balance as of September 30, 2017	$ 4,167		$ 4,167