Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended								6 Months Ended		9 Months Ended		12 Months Ended
	Aug. 31, 2018	May 31, 2018	Feb. 28, 2018	Nov. 30, 2017	Aug. 31, 2017	May 31, 2017	Feb. 28, 2017	Nov. 30, 2016	Feb. 28, 2018	Feb. 28, 2017	May 31, 2018	May 31, 2017	Aug. 31, 2018	Aug. 31, 2017	Aug. 31, 2016
Income Statement [Abstract]
Revenues	$ 8,583,982	$ 9,087,328	$ 6,980,153	$ 8,031,884	$ 7,996,339	$ 8,638,410	$ 7,400,773	$ 8,001,904	$ 15,012,037	$ 15,402,677	$ 24,099,365	$ 24,041,087	$ 32,683,347	$ 32,037,426	$ 30,355,260
Cost of goods sold	8,192,620	8,841,361	6,844,849	7,711,057	7,904,713	8,417,264	7,165,265	7,655,524	14,555,906	14,820,789	23,397,267	23,238,053	31,589,887	31,142,766	29,386,515
Gross profit	391,362	245,967	135,304	320,827	91,626	221,146	235,508	346,380	456,131	581,888	702,098	803,034	1,093,460	894,660	968,745
Marketing, general and administrative	186,291	161,579	186,713	139,500	145,236	155,347	160,166	151,258	326,213	311,424	487,792	466,771	674,083	612,007	601,266
Reserve and impairment charges (recoveries), net	(18,765)	(3,811)	(11,346)	(3,787)	39,170	326,779	72,373	18,357	(15,133)	90,730	(18,944)	417,509	(37,709)	456,679	75,036
Operating earnings (loss)	223,836	88,199	(40,063)	185,114	(92,780)	(260,980)	2,969	176,765	145,051	179,734	233,250	(81,246)	457,086	(174,026)	292,443
(Gain) loss on disposal of business	(61)	(124,050)	(7,705)	0	704	(1,224)	(1,395)	4,105	(7,705)	2,710	(131,755)	1,486	(131,816)	2,190	0
Interest expense	18,984	49,340	40,176	40,702	53,828	39,201	39,945	38,265	80,878	78,210	130,218	117,411	149,202	171,239	113,704
Other (income) loss	(27,015)	(14,622)	(11,364)	(25,014)	(25,407)	(11,952)	(18,083)	(44,509)	(36,378)	(62,592)	(51,000)	(74,544)	(78,015)	(99,951)	(47,609)
Equity (income) loss from investments	(16,404)	(59,308)	(39,441)	(38,362)	(12,817)	(48,393)	(35,800)	(40,328)	(77,803)	(76,128)	(137,111)	(124,521)	(153,515)	(137,338)	(175,777)
Income (loss) before income taxes	248,332	236,839	(21,729)	207,788	(109,088)	(238,612)	18,302	219,232	186,059	237,534	422,898	(1,078)	671,230	(110,166)	402,125
Income tax expense (benefit)	7,787	55,219	(187,688)	20,606	(34,761)	(166,124)	3,685	16,076	(167,082)	19,761	(111,863)	(146,363)	(104,076)	(181,124)	19,099
Net income (loss)	240,545	181,620	165,959	187,182	(74,327)	(72,488)	14,617	203,156	353,141	217,773	534,761	145,285	775,306	70,958	383,026
Net income (loss) attributable to noncontrolling interests	98	(187)	(48)	(464)	123	(955)	406	(208)	(512)	198	(699)	(757)	(601)	(634)	(223)
Comprehensive income attributable to CHS Inc.	$ 240,447	$ 181,807	$ 166,007	$ 187,646	$ (74,450)	$ (71,533)	$ 14,211	$ 203,364	$ 353,653	$ 217,575	$ 535,460	$ 146,042	$ 775,907	$ 71,592	$ 383,249