Valuation And Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Aug. 31, 2018	Aug. 31, 2017	Aug. 31, 2016
Allowance For Doubtful Accounts [Member]
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at beginning of period	$ 7,447	$ 8,312	$ 9,706
Charges to costs and expenses	744	483	800
Deductions	4,606	1,348	2,194
Balance at end of period	3,585	7,447	8,312
Deferred Tax Asset Valuation Allowance [Member]
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at beginning of period	2,804	2,825	2,949
Charges to costs and expenses	758
Deductions		21	124
Balance at end of period	$ 3,562	$ 2,804	$ 2,825