Goodwill and Other Intangible Assets (Changes in goodwill) (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Goodwill [Roll Forward]
Goodwill at beginning of period			$ 63,934	$ 72,365	$ 58,554
Acquisitions			0	47,735	13,811
Impairments			0	(56,166)	0
Goodwill at end of period	$ 63,934		63,934	63,934	72,365
Grain
Goodwill [Roll Forward]
Goodwill at beginning of period			0	46,422	38,165
Acquisitions			0	0	8,257
Impairments	(54,200)			(46,422)
Goodwill at end of period	0		0	0	46,422
Plant Nutrient
Goodwill [Roll Forward]
Goodwill at beginning of period			59,767	21,776	16,222
Acquisitions			0	47,735	5,554
Impairments		$ (2,000)		(9,744)
Goodwill at end of period	59,767		59,767	59,767	21,776
Rail
Goodwill [Roll Forward]
Goodwill at beginning of period			4,167	4,167	4,167
Acquisitions			0	0	0
Impairments				0
Goodwill at end of period	$ 4,167		$ 4,167	$ 4,167	$ 4,167