Valuation And Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Aug. 31, 2017	Aug. 31, 2016	Aug. 31, 2015
Allowance For Doubtful Accounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of period	$ 8,312	$ 9,706	$ 4,857
Charges to costs and expenses	483	800	5,840
Deductions	1,348	2,194	991
Balance at end of period	7,447	8,312	9,706
Allowance For Inventory Obsolescence [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of period	4,656	4,405	2,858
Charges to costs and expenses	1,133	1,262	3,302
Charged to other accounts	49	(30)	(147)
Deductions	827	980	1,608
Balance at end of period	5,011	4,656	4,405
Deferred Tax Asset Valuation Allowance [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of period	2,825	2,949
Charges to costs and expenses			2,949
Deductions	21	124
Balance at end of period	$ 2,804	$ 2,825	$ 2,949