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, 2015	Dec. 31, 2014	Dec. 31, 2013
Goodwill [Roll Forward]
Goodwill at beginning of period			$ 72,365	$ 58,554	$ 54,387
Acquisitions			47,735	13,811	4,167
Impairments			(56,166)	0	0
Goodwill at end of period	$ 63,934		63,934	72,365	58,554
Grain
Goodwill [Roll Forward]
Goodwill at beginning of period			46,422	38,165	38,165
Acquisitions			0	8,257	0
Impairments	(54,200)		(46,422)
Goodwill at end of period	0		0	46,422	38,165
Plant Nutrient
Goodwill [Roll Forward]
Goodwill at beginning of period			21,776	16,222	16,222
Acquisitions			47,735	5,554	0
Impairments		$ (2,000)	(9,744)
Goodwill at end of period	59,767		59,767	21,776	16,222
Rail
Goodwill [Roll Forward]
Goodwill at beginning of period			4,167	$ 4,167	0
Acquisitions			0		4,167
Impairments			0
Goodwill at end of period	$ 4,167		$ 4,167	$ 4,167	$ 4,167