Industry Segment Information (Schedule Of Revenue By Geographical Areas)(Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Aug. 31, 2012	Aug. 31, 2011	Aug. 31, 2010
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 551,255	$ 478,890	$ 358,440
Percent of revenues	100.00%	100.00%	100.00%
Long lived tangible assets	56,180	58,465	57,646
Percent of long lived tangible assets	100.00%	100.00%	100.00%
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	354,649	307,694	204,465
Percent of revenues	64.00%	64.00%	57.00%
Long lived tangible assets	45,100	45,091	45,881
Percent of long lived tangible assets	80.00%	77.00%	80.00%
International [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	196,606	171,196	153,975
Percent of revenues	36.00%	36.00%	43.00%
Long lived tangible assets	$ 11,080	$ 13,374	$ 11,765
Percent of long lived tangible assets	20.00%	23.00%	20.00%