Derivative Financial Instruments and Hedging Activities - Derivatives (Details) $ in Thousands, bbl in Millions	3 Months Ended	12 Months Ended
	Nov. 30, 2019 USD ($) bbl	Aug. 31, 2019 USD ($) bbl
Derivative [Line Items]
Derivative Liability, Noncurrent	$ 6,800	$ 7,400
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	152,237	180,894
Derivative Assets	183,068	246,728
Derivative Asset, Fair Value, Gross Amount Not Offset on Balance Sheet	30,831	65,834
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	157,911	191,073
Derivative Liabilities	202,322	244,019
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	3,030	4,191
Derivative Liability, Fair Value, Gross Amount Not Offset on Balance Sheet	41,381	48,755
Embedded Derivative, Gain on Embedded Derivative	$ 1,600
Credit Rating Agencies Threshold, Minimum	66.67%
Derivative Asset, Noncurrent, Excluding Fair Value Hedges	$ 18,600	26,600
CF Nitrogen LLC [Member]
Derivative [Line Items]
Annual Payment Receivable Contingent On Investment Credit Rating	5,000
Embedded derivative asset	17,900
Foreign exchange derivatives | Not Designated as Hedging Instrument
Derivative [Line Items]
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	1,886	3,226
Derivative Assets	5,518	10,334
Derivative Asset, Fair Value, Gross Amount Not Offset on Balance Sheet	3,632	7,108
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	15,665	13,501
Derivative Liabilities	19,297	20,609
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	0	0
Derivative Liability, Fair Value, Gross Amount Not Offset on Balance Sheet	3,632	7,108
Derivative, Notional Amount	972,200	894,700
Embedded Derivative Financial Instruments [Member] | Not Designated as Hedging Instrument
Derivative [Line Items]
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	17,933	21,364
Derivative Assets	17,933	21,364
Derivative Asset, Fair Value, Gross Amount Not Offset on Balance Sheet	0	0
Commodity derivatives | Not Designated as Hedging Instrument
Derivative [Line Items]
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	132,418	156,304
Derivative Assets	159,617	215,030
Derivative Asset, Fair Value, Gross Amount Not Offset on Balance Sheet	27,199	58,726
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	142,246	177,572
Derivative Liabilities	183,025	223,410
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	3,030	4,191
Derivative Liability, Fair Value, Gross Amount Not Offset on Balance Sheet	37,749	$ 41,647
Fair Value Hedging | Interest rate swap derivatives | Designated as Hedging Instrument
Derivative [Line Items]
Derivative, Notional Amount	$ 365,000
Cash Flow Hedging
Derivative [Line Items]
Aggregate notional amount of cash flow hedges (in barrels) | bbl	9.1	7.7
Cash Flow Hedging | Designated as Hedging Instrument
Derivative [Line Items]
Derivative Assets	$ 26,112	$ 33,179
Derivative Liabilities	$ 5,387	$ 5,351