Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Segment Reporting Information [Line Items]
Revenues from external customers	$ 993,662	$ 1,064,244	$ 1,845,678	$ 1,952,123
Income (loss) before income taxes	(19,065)	23,109	(24,635)	201
Identifiable assets	1,911,425	2,107,415	1,911,425	2,107,415	$ 2,232,849
Operating Segments | Grain
Segment Reporting Information [Line Items]
Revenues from external customers	488,447	522,989	966,975	1,061,803
Income (loss) before income taxes	6,929	(13,037)	1,856	(30,442)
Identifiable assets	783,316	879,055	783,316	879,055	961,114
Operating Segments | Ethanol
Segment Reporting Information [Line Items]
Revenues from external customers	187,831	142,520	341,984	257,213
Income (loss) before income taxes	4,660	6,187	6,376	3,507
Identifiable assets	170,730	192,470	170,730	192,470	171,115
Operating Segments | Plant Nutrient
Segment Reporting Information [Line Items]
Revenues from external customers	264,736	320,036	411,323	487,027
Income (loss) before income taxes	(25,825)	23,535	(19,154)	25,239
Identifiable assets	351,871	448,225	351,871	448,225	484,455
Operating Segments | Rail
Segment Reporting Information [Line Items]
Revenues from external customers	38,149	40,342	78,539	79,951
Income (loss) before income taxes	5,860	6,569	11,938	15,944
Identifiable assets	448,417	388,456	448,417	388,456	398,446
Operating Segments | Retail
Segment Reporting Information [Line Items]
Revenues from external customers	14,499	38,357	46,857	66,129
Income (loss) before income taxes	(6,718)	1,010	(13,564)	(1,066)
Identifiable assets	11,830	43,878	11,830	43,878	31,257
Segment Reconciling Items
Segment Reporting Information [Line Items]
Revenues from external customers	486	643	1,014	2,720
Segment Reconciling Items | Grain
Segment Reporting Information [Line Items]
Revenues from external customers	141	174	207	1,625
Segment Reconciling Items | Plant Nutrient
Segment Reporting Information [Line Items]
Revenues from external customers	70	114	241	361
Segment Reconciling Items | Rail
Segment Reporting Information [Line Items]
Revenues from external customers	275	355	566	734
Other
Segment Reporting Information [Line Items]
Income (loss) before income taxes	(3,907)	(2,173)	(12,077)	(13,073)
Identifiable assets	145,261	155,331	145,261	155,331	$ 186,462
Noncontrolling interests
Segment Reporting Information [Line Items]
Income (loss) before income taxes	$ (64)	$ 1,018	$ (10)	$ 92