Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Aug. 31, 2017	Aug. 31, 2016	Aug. 31, 2015
Increase (Decrease) In Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	$ 501,432	$ 538,551	$ 775,977
Other comprehensive income (loss) before reclassifications	4,188	(2,669)	(31,530)
Income tax benefit (expense)	(194)	167	688
Other comprehensive income (loss) before reclassifications, net of tax	3,994	(2,502)	(30,842)
Amounts reclassified from accumulated other comprehensive loss	851	1,000	5,498
Income tax benefit	(23)	(91)	(537)
Amounts reclassified from accumulated other comprehensive loss, net of tax	828	909	4,961
Total other comprehensive income (loss), net of tax	4,822	(1,593)	(25,881)
Ending Balance	537,493	501,432	538,551
Foreign Currency Translation Adjustments
Increase (Decrease) In Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(34,539)	(34,009)	(10,663)
Other comprehensive income (loss) before reclassifications	2,711	(530)	(23,346)
Income tax benefit (expense)	0	0	0
Other comprehensive income (loss) before reclassifications, net of tax	2,711	(530)	(23,346)
Amounts reclassified from accumulated other comprehensive loss	0	0	0
Income tax benefit	0	0	0
Amounts reclassified from accumulated other comprehensive loss, net of tax	0	0	0
Total other comprehensive income (loss), net of tax	2,711	(530)	(23,346)
Ending Balance	(31,828)	(34,539)	(34,009)
Pension Obligations, net
Increase (Decrease) In Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(5,576)	(4,273)	(2,036)
Other comprehensive income (loss) before reclassifications	1,477	(2,139)	(2,874)
Income tax benefit (expense)	(194)	167	260
Other comprehensive income (loss) before reclassifications, net of tax	1,283	(1,972)	(2,614)
Amounts reclassified from accumulated other comprehensive loss	851	688	575
Income tax benefit	(23)	(19)	(198)
Amounts reclassified from accumulated other comprehensive loss, net of tax	828	669	377
Total other comprehensive income (loss), net of tax	2,111	(1,303)	(2,237)
Ending Balance	(3,465)	(5,576)	(4,273)
Net Unrealized Gain (Loss) on Cash Flow Hedges
Increase (Decrease) In Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	0	(240)	58
Other comprehensive income (loss) before reclassifications	0	0	(5,310)
Income tax benefit (expense)	0	0	428
Other comprehensive income (loss) before reclassifications, net of tax	0	0	(4,882)
Amounts reclassified from accumulated other comprehensive loss	0	312	4,923
Income tax benefit	0	(72)	(339)
Amounts reclassified from accumulated other comprehensive loss, net of tax	0	240	4,584
Total other comprehensive income (loss), net of tax	0	240	(298)
Ending Balance	0	0	(240)
Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) In Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(40,115)	(38,522)	(12,641)
Ending Balance	$ (35,293)	$ (40,115)	$ (38,522)