Concentration of Risk and Segment Data (Segment Assets) (Details 5) - USD ($) $ in Thousands	Aug. 31, 2017	Aug. 31, 2016
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 11,095,995	$ 10,322,677
EMS [Member] | Operating Segments [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	2,778,820	2,615,237
DMS [Member] | Operating Segments [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	5,290,468	5,012,798
Other non-allocated assets | Operating Segments [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 3,026,707	$ 2,694,642