Income Taxes (Components Of Provision For Income Taxes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Aug. 31, 2017	Aug. 31, 2016	Aug. 31, 2015
Current:
Federal	$ 30,352	$ 20,137	$ 14,597
State	3,921	3,791	3,576
Current	34,273	23,928	18,173
Deferred:
Federal	(2,378)	4,372	10,592
State	(91)	137	(1,528)
Deferred	(2,469)	4,509	9,064
Provision for income taxes	$ 31,804	$ 28,437	$ 27,237