Correction of immaterial errors (Details) - USD ($) $ in Thousands	3 Months Ended
	Nov. 30, 2015	Nov. 30, 2014
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Cost of goods sold	$ 7,316,974	$ 8,907,441
Gross profit	411,818	592,027
Operating earnings	259,814	430,059
Interest expense, net	6,993	21,905
Income before income taxes	289,855	435,658
Depreciation and amortization	100,350	83,180
Accounts payable and accrued expenses	596,881	546,637
Net Cash Provided by (Used in) Operating Activities	416,099	26,537
Acquisition of property, plant and equipment	(251,678)	(302,701)
Expenditures for Major Repairs	(18,897)	(1,337)
Net Cash Provided by (Used in) Investing Activities	(400,480)	(830,755)
Principal payments on capital lease obligations		(10,129)
Other financing activities, net	0	148
Net Cash Provided by (Used in) Financing Activities	$ 285,900	347,950
Scenario, Previously Reported [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Cost of goods sold		8,908,745
Gross profit		590,723
Operating earnings		428,755
Interest expense, net		20,601
Income before income taxes		435,658
Depreciation and amortization		73,322
Accounts payable and accrued expenses		510,966
Net Cash Provided by (Used in) Operating Activities		(18,992)
Acquisition of property, plant and equipment		(267,279)
Expenditures for Major Repairs		(1,088)
Net Cash Provided by (Used in) Investing Activities		(795,084)
Principal payments on capital lease obligations		0
Other financing activities, net		(118)
Net Cash Provided by (Used in) Financing Activities		357,808
Scenario, Adjustment [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Cost of goods sold		(1,304)
Gross profit		1,304
Operating earnings		1,304
Interest expense, net		1,304
Income before income taxes		0
Depreciation and amortization		9,858
Accounts payable and accrued expenses		35,671
Net Cash Provided by (Used in) Operating Activities		45,529
Acquisition of property, plant and equipment		(35,422)
Expenditures for Major Repairs		(249)
Net Cash Provided by (Used in) Investing Activities		(35,671)
Principal payments on capital lease obligations		(10,129)
Other financing activities, net		266
Net Cash Provided by (Used in) Financing Activities		$ (9,858)