Consolidated Statements of Stockholders' Equity (USD $) In Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Noncontrolling Interest [Member]
Balance at Aug. 31, 2010	$ 493,140	$ 47,690	$ 249,734	$ (6,278)	$ 519,649	$ (322,777)	$ 5,122
Comprehensive income (loss)	97,970			56,285	40,996		689
Cash dividends paid	(19,389)				(19,389)
Cash distributions to noncontrolling interests	(700)						(700)
Capital contributions from noncontrolling interests	690						690
Purchase of treasury stock	(22,154)					(22,154)
Issuance of treasury stock	199		27			172
Stock options exercised	969	52	917
Restricted stock issued, net of forfeitures	0	121	(121)
Redemption of common stock to cover tax withholdings	(1,043)	(47)	(996)
Amortization of restricted stock	4,623		4,623
Balance at Aug. 31, 2011	554,305	47,816	254,184	50,007	541,256	(344,759)	5,801
Comprehensive income (loss)	(3,969)			(55,928)	50,887		1,072
Cash dividends paid	(20,938)				(20,938)
Cash distributions to noncontrolling interests	(580)						(580)
Purchase of treasury stock	(26,752)					(26,752)
Issuance of treasury stock	432		20			412
Stock options exercised	915	51	864
Restricted stock issued, net of forfeitures	0	108	(108)
Redemption of common stock to cover tax withholdings	(382)	(17)	(365)
Amortization of restricted stock	4,658		4,658
Balance at Aug. 31, 2012	507,689	47,958	259,253	(5,921)	571,205	(371,099)	6,293
Comprehensive income (loss)	33,776			6,603	26,099		1,074
Cash dividends paid	(22,934)				(22,934)
Cash distributions to noncontrolling interests	0
Purchase of treasury stock	(8,091)					(8,091)
Issuance of treasury stock	356		93			263
Stock options exercised	1,205	64	1,141
Restricted stock issued, net of forfeitures	0	93	(93)
Redemption of common stock to cover tax withholdings	(396)	(21)	(375)
Amortization of restricted stock	3,139		3,139
Balance at Aug. 31, 2013	$ 514,744	$ 48,094	$ 263,158	$ 682	$ 574,370	$ (378,927)	$ 7,367