CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Tax benefit from stock-based compensation [Member]	Accumulated other comprehensive loss [Member]	Retained Earnings [Member]	Treasury Stock [Member]
Balance at Aug. 31, 2012	$ 418,914	$ 3	$ 384,154	$ 6,680	$ (33,182)	$ 77,739	$ (16,480)
Balance (in shares) at Aug. 31, 2012		30,856					645
Purchase of treasury stock	(3,467)						$ (3,467)
Purchase of treasury stock (in shares)							45
Issuance of restricted stock award (in shares)		64
Forfeiture of restricted stock awards (in shares)		(2)
Exercise of stock options (in shares)		6
Exercise of stock options	125		125
Stock-based compensation	7,638		6,302	1,336
Dividend paid to stockholders	(18,133)					(18,133)
Net income	84,265					84,265
Other Comprehensive Income (Loss), Net of Tax	(8,293)				(8,293)
Balance at Aug. 31, 2013	481,049	$ 3	390,581	8,016	(41,475)	143,871	$ (19,947)
Balance (in shares) at Aug. 31, 2013		30,924					690
Purchase of treasury stock	(4,773)						$ (4,773)
Purchase of treasury stock (in shares)							51
Issuance of restricted stock award (in shares)		24
Forfeiture of restricted stock awards (in shares)		(2)
Exercise of stock options (in shares)		5
Exercise of stock options	118		118
Stock-based compensation	7,940		6,451	1,489
Dividend paid to stockholders	(21,144)					(21,144)
Net income	92,886					92,886
Other Comprehensive Income (Loss), Net of Tax	(7,811)				(7,811)
Balance at Aug. 31, 2014	548,265	$ 3	397,150	9,505	(49,286)	215,613	$ (24,720)
Balance (in shares) at Aug. 31, 2014		30,951					741
Purchase of treasury stock	(4,677)						$ (4,677)
Purchase of treasury stock (in shares)							52
Issuance of restricted stock award (in shares)		33
Forfeiture of restricted stock awards (in shares)		(9)
Exercise of stock options (in shares)		3
Exercise of stock options	49		49
Stock-based compensation	7,175		5,969	1,206
Dividend paid to stockholders	(21,126)					(21,126)
Net income	89,124					89,124
Other Comprehensive Income (Loss), Net of Tax	(52,226)				(52,226)
Balance at Aug. 31, 2015	$ 566,584	$ 3	$ 403,168	$ 10,711	$ (101,512)	$ 283,611	$ (29,397)
Balance (in shares) at Aug. 31, 2015		30,978					793