Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	May 31, 2017	May 31, 2016	May 31, 2017	May 31, 2016
Increase (Decrease) In Accumulated Other Comprehensive Loss [Roll Forward}
Balance - Beginning of period			$ 501,432	$ 538,551
Other comprehensive income (loss) before reclassifications	$ (694)	$ 1,485	(1,439)	(416)
Income tax expense	0	0	(194)	0
Other comprehensive income (loss) before reclassifications, net of tax	(694)	1,485	(1,633)	(416)
Amounts reclassified from accumulated other comprehensive loss	420	102	670	580
Income tax benefit	(154)	(37)	(244)	(170)
Amounts reclassified from accumulated other comprehensive loss, net of tax	266	65	426	410
Total other comprehensive income (loss), net of tax	(428)	1,550	(1,207)	(6)
Balance - May 31 (End of period)	517,558	488,930	517,558	488,930
Foreign Currency Translation Adjustments
Increase (Decrease) In Accumulated Other Comprehensive Loss [Roll Forward}
Balance - Beginning of period	(35,333)	(35,910)	(34,539)	(34,009)
Other comprehensive income (loss) before reclassifications	(694)	1,485	(1,488)	(416)
Income tax expense	0	0	0	0
Other comprehensive income (loss) before reclassifications, net of tax	(694)	1,485	(1,488)	(416)
Amounts reclassified from accumulated other comprehensive loss	0	0	0	0
Income tax benefit	0	0	0	0
Amounts reclassified from accumulated other comprehensive loss, net of tax	0	0	0	0
Total other comprehensive income (loss), net of tax	(694)	1,485	(1,488)	(416)
Balance - May 31 (End of period)	(36,027)	(34,425)	(36,027)	(34,425)
Pension Obligations, net
Increase (Decrease) In Accumulated Other Comprehensive Loss [Roll Forward}
Balance - Beginning of period	(5,561)	(4,168)	(5,576)	(4,273)
Other comprehensive income (loss) before reclassifications	0	0	49	0
Income tax expense	0	0	(194)	0
Other comprehensive income (loss) before reclassifications, net of tax	0	0	(145)	0
Amounts reclassified from accumulated other comprehensive loss	420	102	670	268
Income tax benefit	(154)	(37)	(244)	(98)
Amounts reclassified from accumulated other comprehensive loss, net of tax	266	65	426	170
Total other comprehensive income (loss), net of tax	266	65	281	170
Balance - May 31 (End of period)	(5,295)	(4,103)	(5,295)	(4,103)
Net Unrealized Gain (Loss) on Cash Flow Hedges
Increase (Decrease) In Accumulated Other Comprehensive Loss [Roll Forward}
Balance - Beginning of period		0		(240)
Other comprehensive income (loss) before reclassifications		0		0
Income tax expense		0		0
Other comprehensive income (loss) before reclassifications, net of tax		0		0
Amounts reclassified from accumulated other comprehensive loss		0		312
Income tax benefit		0		(72)
Amounts reclassified from accumulated other comprehensive loss, net of tax		0		240
Total other comprehensive income (loss), net of tax		0		240
Balance - May 31 (End of period)		0		0
AOCI Attributable to Parent
Increase (Decrease) In Accumulated Other Comprehensive Loss [Roll Forward}
Balance - Beginning of period	(40,894)	(40,078)	(40,115)	(38,522)
Balance - May 31 (End of period)	$ (41,322)	$ (38,528)	$ (41,322)	$ (38,528)