SEGMENT REPORTING - Information Regarding Geography and Countries (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Aug. 31, 2017	May 31, 2017	Feb. 28, 2017	Nov. 30, 2016	Aug. 31, 2016	May 31, 2016	Feb. 29, 2016	Nov. 30, 2015	Aug. 31, 2017	Aug. 31, 2016	Aug. 31, 2015
Segment Reporting Information [Line Items]
Net revenues	$ 9,149,958	$ 8,867,036	$ 8,317,671	$ 8,515,517	$ 8,489,238	$ 8,434,757	$ 7,945,565	$ 8,013,163	$ 34,850,182	$ 32,882,723	$ 31,047,931
Reimbursements	490,948	489,751	444,511	490,086	476,342	534,287	451,488	452,821	1,915,296	1,914,938	1,866,493
Revenues	9,640,906	$ 9,356,787	$ 8,762,182	$ 9,005,603	8,965,580	$ 8,969,044	$ 8,397,053	$ 8,465,984	36,765,478	34,797,661	32,914,424
Property and equipment, net as of August 31	1,140,598				956,542				1,140,598	956,542	801,884
North America
Segment Reporting Information [Line Items]
Net revenues									16,290,842	15,653,290	14,209,387
Reimbursements									963,911	970,248	891,443
Revenues									17,254,753	16,623,538	15,100,830
Property and equipment, net as of August 31	274,463				244,351				274,463	244,351	230,359
Europe
Segment Reporting Information [Line Items]
Net revenues									11,933,093	11,448,361	10,929,572
Reimbursements									622,579	635,362	628,342
Revenues									12,555,672	12,083,723	11,557,914
Property and equipment, net as of August 31	294,154				220,500				294,154	220,500	179,925
Growth Markets
Segment Reporting Information [Line Items]
Net revenues									6,626,247	5,781,072	5,908,972
Reimbursements									328,806	309,328	346,708
Revenues									6,955,053	6,090,400	6,255,680
Property and equipment, net as of August 31	$ 571,981				$ 491,691				$ 571,981	$ 491,691	$ 391,600