Note 7 - Segment Information (Details) - Results of Operations (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	May 31, 2014	May 31, 2013	May 31, 2014	May 31, 2013	Aug. 31, 2013
Segment Reporting Information [Line Items]
Revenues from clients	$ 231,761	$ 214,613	$ 681,671	$ 638,779
Segment operating profit	73,037	71,637	222,833	198,885
Total assets	659,636	735,330	659,636	735,330	690,197
Capital expenditures	3,672	4,204	11,704	13,288
UNITED STATES
Segment Reporting Information [Line Items]
Revenues from clients	156,241	146,972	463,419	436,947
Segment operating profit	39,081	38,529	121,806	102,654
Total assets	363,959	502,108	363,959	502,108
Capital expenditures	3,099	3,580	10,529	8,889
Europe [Member]
Segment Reporting Information [Line Items]
Revenues from clients	58,265	52,358	167,993	155,638
Segment operating profit	24,732	25,333	75,155	74,275
Total assets	237,286	181,346	237,286	181,346
Capital expenditures	188	276	380	993
Asia Pacific [Member]
Segment Reporting Information [Line Items]
Revenues from clients	17,255	15,283	50,259	46,194
Segment operating profit	9,224	7,775	25,872	21,956
Total assets	58,391	51,876	58,391	51,876
Capital expenditures	$ 385	$ 348	$ 795	$ 3,406