CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $) In Thousands, except Share data	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, 2011	$ 375,838	$ 3	$ 383,549	$ 5,242	$ (22,915)	$ 28,238	$ (18,279)
Balance (in shares) at Aug. 31, 2011		30,696,000					796,000
Purchase of treasury stock	(3,154)						(3,154)
Purchase of treasury stock (in shares)							46,000
Stock Issued During Period, Shares, Treasury Stock Reissued	(196,850)	(197,000)					(197,000)
Stock Issued During Period, Value, Treasury Stock Reissued			(4,953)				4,953
Issuance of restricted stock award (in shares)		353,000
Forfeiture of restricted stock awards (in shares)		(2,000)
Exercise of stock options (in shares)		6,000
Exercise of stock options	89		89
Stock-based compensation	6,907		5,469	1,438
Dividend paid to stockholders	(18,120)					(18,120)
Net income	67,621					67,621
Other Comprehensive Income (Loss), Net of Tax	(10,267)				(10,267)
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		30,856,000					645,000
Purchase of treasury stock	(3,467)						(3,467)
Purchase of treasury stock (in shares)							45,000
Stock Issued During Period, Shares, Treasury Stock Reissued	0
Issuance of restricted stock award (in shares)		64,000
Forfeiture of restricted stock awards (in shares)		(2,000)
Exercise of stock options (in shares)		6,000
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		30,924,000					690,000
Purchase of treasury stock	(4,773)						(4,773)
Purchase of treasury stock (in shares)							51,000
Stock Issued During Period, Shares, Treasury Stock Reissued	0
Issuance of restricted stock award (in shares)		24,000
Forfeiture of restricted stock awards (in shares)		(2,000)
Exercise of stock options (in shares)		5,000
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		30,951,000					741,000