Restatement of Previously Issued Financial Information - Summary of Impacts of the Restatement Adjustments on Previously Reported Consolidated Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended
	Nov. 30, 2018	Nov. 30, 2017
Cash flows from operating activities:
Net income (loss)	$ 347,115	$ 187,182
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	118,603	120,148
Amortization of deferred major repair costs	19,176	16,418
Equity (income) loss from investments	(66,508)	(38,362)
Distributions from equity investments	18,887	12,514
Provision for doubtful accounts	5,009	(3,601)
Deferred taxes		16,346
Other, net	(3,162)	375
Changes in operating assets and liabilities, net of acquisitions:
Receivables	(182,767)	(56,700)
Inventories	(416,196)	(513,023)
Derivative assets	(139,694)	(63,926)
Margin and related deposits	(63,476)	(893)
Supplier advance payments	(110,672)	(293,536)
Other current assets and other assets	12,541	6,323
Customer margin deposits and credit balances	(3,697)	(18,045)
Customer advance payments	(83,271)	(10,251)
Accounts payable and accrued expenses	299,741	453,219
Derivative liabilities	(159,385)	(99,956)
Other liabilities	7,015	4,376
Net cash provided by (used in) operating activities	(94,798)	(153,540)
Cash flows from investing activities:
Acquisition of property, plant and equipment	(104,750)	(85,824)
Proceeds from disposition of property, plant and equipment	5,752	56,079
Proceeds from sale of business	1,730	29,457
Expenditures for major repairs	(3,441)	(1,039)
Investments redeemed		5,195
Changes in CHS Capital notes receivable, net	(126,865)	(69,227)
Financing extended to customers	(3,928)	(15,778)
Financing extended to customers		16,520
Other investing activities, net	4,090	1,847
Net cash provided by (used in) investing activities	(154,776)	(62,770)
Cash flows from financing activities:
Proceeds from lines of credit and long-term borrowings		8,006,980
Payments on lines of credit, long-term borrowings and capital lease obligations	(4,317,479)	(7,654,661)
Preferred stock dividends paid	(42,167)	(42,167)
Redemptions of equities	(24,072)	(3,682)
Other financing activities, net	3,503	(21,257)
Net cash provided by (used in) financing activities	49,061	285,213
Effect of exchange rate changes on cash and cash equivalents	(1,535)	2,236
Net increase (decrease) in cash and cash equivalents and restricted cash	(202,048)	71,139
Cash and cash equivalents and restricted cash at beginning of period	543,940	272,272
Cash and cash equivalents and restricted cash at end of period	$ 341,892	343,411
As Previously Reported
Cash flows from operating activities:
Net income (loss)		179,619
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization		120,148
Amortization of deferred major repair costs		16,418
Equity (income) loss from investments		(38,362)
Distributions from equity investments		12,514
Provision for doubtful accounts		(3,601)
Deferred taxes		15,044
Other, net		2,976
Changes in operating assets and liabilities, net of acquisitions:
Receivables		(80,637)
Inventories		(472,180)
Derivative assets		67,365
Margin and related deposits		(893)
Supplier advance payments		(292,905)
Other current assets and other assets		2,689
Customer margin deposits and credit balances		(18,045)
Customer advance payments		1,278
Accounts payable and accrued expenses		441,071
Derivative liabilities		(97,329)
Other liabilities		4,376
Net cash provided by (used in) operating activities		(140,454)
Cash flows from investing activities:
Acquisition of property, plant and equipment		(85,824)
Proceeds from disposition of property, plant and equipment		56,079
Proceeds from sale of business		29,457
Expenditures for major repairs		(1,039)
Investments redeemed		5,195
Changes in CHS Capital notes receivable, net		(69,227)
Financing extended to customers		(15,778)
Financing extended to customers		16,520
Other investing activities, net		1,847
Net cash provided by (used in) investing activities		(62,770)
Cash flows from financing activities:
Proceeds from lines of credit and long-term borrowings		8,006,980
Payments on lines of credit, long-term borrowings and capital lease obligations		(7,657,713)
Preferred stock dividends paid		(42,167)
Redemptions of equities		(3,682)
Other financing activities, net		(31,680)
Net cash provided by (used in) financing activities		271,738
Effect of exchange rate changes on cash and cash equivalents		2,236
Net increase (decrease) in cash and cash equivalents and restricted cash		70,750
Cash and cash equivalents and restricted cash at beginning of period		181,379
Cash and cash equivalents and restricted cash at end of period		252,129
Restatement Adjustments
Cash flows from operating activities:
Net income (loss)		7,563
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization		0
Amortization of deferred major repair costs		0
Equity (income) loss from investments		0
Distributions from equity investments		0
Provision for doubtful accounts		0
Deferred taxes		1,302
Other, net		(2,601)
Changes in operating assets and liabilities, net of acquisitions:
Receivables		23,937
Inventories		(40,843)
Derivative assets		(3,439)
Margin and related deposits		0
Supplier advance payments		(631)
Other current assets and other assets		883
Customer margin deposits and credit balances		0
Customer advance payments		(11,529)
Accounts payable and accrued expenses		12,148
Derivative liabilities		(2,627)
Other liabilities		0
Net cash provided by (used in) operating activities		(15,837)
Cash flows from investing activities:
Acquisition of property, plant and equipment		0
Proceeds from disposition of property, plant and equipment		0
Proceeds from sale of business		0
Expenditures for major repairs		0
Investments redeemed		0
Changes in CHS Capital notes receivable, net		0
Financing extended to customers		0
Financing extended to customers		0
Other investing activities, net		0
Net cash provided by (used in) investing activities		0
Cash flows from financing activities:
Proceeds from lines of credit and long-term borrowings		0
Payments on lines of credit, long-term borrowings and capital lease obligations		3,052
Preferred stock dividends paid		0
Redemptions of equities		0
Other financing activities, net		10,423
Net cash provided by (used in) financing activities		13,475
Effect of exchange rate changes on cash and cash equivalents		0
Net increase (decrease) in cash and cash equivalents and restricted cash		(2,362)
Cash and cash equivalents and restricted cash at beginning of period		0
Cash and cash equivalents and restricted cash at end of period		(2,362)
As Restated
Cash flows from operating activities:
Net income (loss)		187,182
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization		120,148
Amortization of deferred major repair costs		16,418
Equity (income) loss from investments		(38,362)
Distributions from equity investments		12,514
Provision for doubtful accounts		(3,601)
Deferred taxes		16,346
Other, net		375
Changes in operating assets and liabilities, net of acquisitions:
Receivables		(56,700)
Inventories		(513,023)
Derivative assets		63,926
Margin and related deposits		(893)
Supplier advance payments		(293,536)
Other current assets and other assets		3,572
Customer margin deposits and credit balances		(18,045)
Customer advance payments		(10,251)
Accounts payable and accrued expenses		453,219
Derivative liabilities		(99,956)
Other liabilities		4,376
Net cash provided by (used in) operating activities		(156,291)
Cash flows from investing activities:
Acquisition of property, plant and equipment		(85,824)
Proceeds from disposition of property, plant and equipment		56,079
Proceeds from sale of business		29,457
Expenditures for major repairs		(1,039)
Investments redeemed		5,195
Changes in CHS Capital notes receivable, net		(69,227)
Financing extended to customers		(15,778)
Financing extended to customers		16,520
Other investing activities, net		1,847
Net cash provided by (used in) investing activities		(62,770)
Cash flows from financing activities:
Proceeds from lines of credit and long-term borrowings		8,006,980
Payments on lines of credit, long-term borrowings and capital lease obligations		(7,654,661)
Preferred stock dividends paid		(42,167)
Redemptions of equities		(3,682)
Other financing activities, net		(21,257)
Net cash provided by (used in) financing activities		285,213
Effect of exchange rate changes on cash and cash equivalents		2,236
Net increase (decrease) in cash and cash equivalents and restricted cash		68,388
Cash and cash equivalents and restricted cash at beginning of period		181,379
Cash and cash equivalents and restricted cash at end of period		249,767
Accounting Standards Update 2016-18
Changes in operating assets and liabilities, net of acquisitions:
Other current assets and other assets		2,751
Net cash provided by (used in) operating activities		2,751
Cash flows from financing activities:
Net increase (decrease) in cash and cash equivalents and restricted cash		2,751
Cash and cash equivalents and restricted cash at beginning of period		90,893
Cash and cash equivalents and restricted cash at end of period		$ 93,644