CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Treasury Stock	Retained Earnings	Accumulated Other Comprehensive Loss	Stock Held in Trust	Deferred Compensation Liability
Shares, Issued at Aug. 31, 2015		78,933
Beginning Balance at Aug. 31, 2015	$ 673,001	$ 15,787	$ 104,308	$ (600,630)	$ 1,367,176	$ (213,640)	$ (4,292)	$ 4,292
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) earnings	(105,174)				(105,174)
Total other comprehensive income (loss), net of tax	(38,183)					(38,183)
Company stock contribution to employee benefit plans and other (in shares)		20
Company stock contribution to employee benefit plans and other	453	$ 4	449
Restricted stock awards, vesting and withhold to cover (in shares)		235
Restricted stock awards issuance and vesting	0	$ 47	(47)
Cash dividend ($0.04 per share)	(2,357)				(2,357)
Treasury stock repurchases	(17,101)			(17,101)
Stock based compensation expense	10,442		10,442
Stock option exercises (in shares)		175
Stock Issued During Period, Value, Stock Options Exercised	3,564	$ 35	3,529
Cash receipts from exercise of options	3,564
Excess tax benefit (shortfall) on stock option exercises	(3,943)		(3,943)
Stock issued to, acquired for and distributed from rabbi trust (in shares)		30
Stock issued to, acquired for and distributed from rabbi trust	248	$ 6	242				1,646	(1,646)
Shares, Issued at Aug. 31, 2016		79,393
Ending Balance at Aug. 31, 2016	520,950	$ 15,879	114,980	(617,731)	1,259,645	(251,823)	(2,646)	2,646
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) earnings	(66,213)				(66,213)
Total other comprehensive income (loss), net of tax	24,562					24,562
Company stock contribution to employee benefit plans and other (in shares)		17
Company stock contribution to employee benefit plans and other	893	$ 3	890
Restricted stock awards, vesting and withhold to cover (in shares)		397
Restricted stock awards issuance and vesting	0	$ 79	(79)
Cash dividend ($0.04 per share)	(2,390)				(2,390)
Stock based compensation expense	16,733		16,733
Stock option exercises (in shares)		374
Stock Issued During Period, Value, Stock Options Exercised	7,762	$ 75	7,687
Cash receipts from exercise of options	7,762
Excess tax benefit (shortfall) on stock option exercises	(2,042)		(2,042)
Stock issued to, acquired for and distributed from rabbi trust (in shares)		19
Stock issued to, acquired for and distributed from rabbi trust	284	$ 4	280				(50)	50
Shares, Issued at Aug. 31, 2017		80,200
Ending Balance at Aug. 31, 2017	500,539	$ 16,040	138,449	(617,731)	1,191,042	(227,261)	(2,696)	2,696
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) earnings	(21,648)				(21,648)
Total other comprehensive income (loss), net of tax	53,016					53,016
Company stock contribution to employee benefit plans and other (in shares)		20
Company stock contribution to employee benefit plans and other	539	$ 4	535
Restricted stock awards, vesting and withhold to cover (in shares)		400
Restricted stock awards issuance and vesting	0	$ 80	(80)
Cash dividend ($0.04 per share)	(2,439)				(2,439)
Stock based compensation expense	14,457		14,457
Stock option exercises (in shares)		780
Stock Issued During Period, Value, Stock Options Exercised		$ 156	14,984
Cash receipts from exercise of options	15,140
Adjustment to Additional Paid in Capital, Income Tax Effect from Net Settlement of Equity Awards	(1,281)		(1,281)
Stock issued to, acquired for and distributed from rabbi trust (in shares)		25
Stock issued to, acquired for and distributed from rabbi trust	389	$ 5	384				246	(246)
Shares, Issued at Aug. 31, 2018		81,424
Ending Balance at Aug. 31, 2018	$ 558,712	$ 16,285	$ 167,448	$ (617,731)	$ 1,166,955	$ (174,245)	$ (2,450)	$ 2,450