CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income	Treasury Stock	Noncontrolling Interests
Beginning Balance at Aug. 31, 2012	$ 2,107,335	$ 232	$ 1,752,847	$ 766,934	$ 106,275	$ (521,231)	$ 2,278
Beginning Balance (in shares) at Aug. 31, 2012		206,028,577
Shares issued upon exercise of stock options	3,366	$ 5	3,361
Shares issued upon exercise of stock options (in shares)		256,419
Shares issued under employee stock purchase plan	$ 14,919	$ 1	14,918
Shares issued under employee stock purchase plan (in shares)	902,691	902,691
Vesting of restricted stock awards (in shares)		4,504,249
Purchases of treasury stock under employee stock plans	$ (20,290)					(20,290)
Purchases of treasury stock under employee stock plans (in shares)	(1,184,162)	(1,184,162)
Treasury shares purchased	$ (129,262)					(129,262)
Treasury shares purchased (in shares)		(7,342,904)
Recognition of stock-based compensation	67,824		67,824
Excess tax benefit of stock awards	14,459		14,459
Declared dividends	(67,241)			(67,241)
Comprehensive income	345,064			371,482	(25,027)		(1,391)
Acquisition/Adjustment of noncontrolling interests	36,548						36,548
Purchase of noncontrolling interests	(17,500)						(17,500)
Capital contribution of noncontrolling interests	316						316
Foreign currency adjustments attributable to noncontrolling interests	29						29
Ending Balance at Aug. 31, 2013	2,355,567	$ 238	1,853,409	1,071,175	81,248	(670,783)	20,280
Ending Balance (in shares) at Aug. 31, 2013		203,164,870
Shares issued upon exercise of stock options (in shares)		1,251
Shares issued under employee stock purchase plan	$ 15,773	$ 6	15,767
Shares issued under employee stock purchase plan (in shares)	1,077,071	1,077,071
Vesting of restricted stock awards (in shares)		5,120,099
Purchases of treasury stock under employee stock plans	$ (34,312)					(34,312)
Purchases of treasury stock under employee stock plans (in shares)	(1,569,059)	(1,569,059)
Treasury shares purchased	$ (260,274)					(260,274)
Treasury shares purchased (in shares)		(13,680,382)
Recognition of stock-based compensation	8,186		8,186
Excess tax benefit of stock awards	(2,396)		(2,396)
Declared dividends	(66,716)			(66,716)
Comprehensive income	247,979			241,313	5,714		952
Acquisition/Adjustment of noncontrolling interests	5,174						5,174
Purchase of noncontrolling interests	(1,720)		(747)				(973)
Sale of noncontrolling interest	(6,898)						(6,898)
Foreign currency adjustments attributable to noncontrolling interests	5						5
Ending Balance at Aug. 31, 2014	$ 2,260,368	$ 244	1,874,219	1,245,772	86,962	(965,369)	18,540
Ending Balance (in shares) at Aug. 31, 2014	194,113,850	194,113,850
Shares issued upon exercise of stock options (in shares)		36,165
Shares issued under employee stock purchase plan	$ 18,060	$ 2	18,058
Shares issued under employee stock purchase plan (in shares)	1,005,916	1,005,916
Vesting of restricted stock awards		$ 1	(1)
Vesting of restricted stock awards (in shares)		1,706,944
Purchases of treasury stock under employee stock plans	$ (7,606)					(7,606)
Purchases of treasury stock under employee stock plans (in shares)	(402,143)	(402,143)
Treasury shares purchased	$ (85,576)					(85,576)
Treasury shares purchased (in shares)		(4,392,664)
Recognition of stock-based compensation	62,826		62,826
Excess tax benefit of stock awards	2		2
Declared dividends	(60,881)			(60,881)
Comprehensive income	147,796			284,019	(137,816)		1,593
Acquisition/Adjustment of noncontrolling interests	329						329
Purchase of noncontrolling interests	(345)						(345)
Foreign currency adjustments attributable to noncontrolling interests	38						38
Ending Balance at Aug. 31, 2015	$ 2,335,011	$ 247	$ 1,955,104	$ 1,468,910	$ (50,854)	$ (1,058,551)	$ 20,155
Ending Balance (in shares) at Aug. 31, 2015	192,068,068	192,068,068