Warranties (Schedule Of Product Warranty Liability) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Feb. 29, 2012	Feb. 28, 2011	Feb. 29, 2012	Feb. 28, 2011
Warranties [Abstract]
Product warranty accrual balance, beginning of period	$ 3,745	$ 1,796	$ 3,651	$ 1,862
Liabilities accrued for warranties during the period	836	843	1,735	1,685
Warranty claims paid during the period	(752)	(723)	(1,557)	(1,631)
Product warranty accrual balance, end of period	$ 3,829	$ 1,916	$ 3,829	$ 1,916