CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Feb. 28, 2018	Aug. 31, 2017
CONSOLIDATED BALANCE SHEETS [Abstract]
Receivables, allowance for doubtful account	$ 0	$ 7
Other non-current assets, fair value of derivative instruments	4,030	2,547
Other long-term liabilities, fair value of derivative instruments	670	682
Other long-term liabilities, defined benefit plan	$ 5,688	$ 5,051
Common stock, par value per share	$ 0.0001	$ 0.0001
Common stock, shares authorized	45,000,000	45,000,000
Common stock, shares issued	31,310,880	31,275,727
Common stock, shares outstanding	30,414,382	30,400,742
Treasury stock, shares	896,498	874,985