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, 2013	$ 2,355,567	$ 238	$ 1,853,409	$ 1,071,175	$ 81,248	$ (670,783)	$ 20,280
Beginning 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
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
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
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
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
Declared dividends to noncontrolling interests	1,500						1,500
Acquisition/Adjustment of noncontrolling interests							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
Shares issued upon exercise of stock options (in shares)		19,109
Shares issued under employee stock purchase plan	$ 20,911	$ 1	20,910
Shares issued under employee stock purchase plan (in shares)		1,246,947
Vesting of restricted stock awards		$ 2	(2)
Vesting of restricted stock awards (in shares)		1,817,635
Purchases of treasury stock under employee stock plans	$ (10,656)					(10,656)
Purchases of treasury stock under employee stock plans (in shares)	(462,900)	(462,900)
Treasury shares purchased	$ (148,340)					(148,340)
Treasury shares purchased (in shares)		(7,690,387)
Recognition of stock-based compensation	58,997		58,997
Declared dividends	(62,185)			(62,185)
Comprehensive income	265,873			254,095	10,977		801
Declared dividends to noncontrolling interests	(1,500)						(1,500)
Purchase of noncontrolling interests	(600)		(484)				(116)
Foreign currency adjustments attributable to noncontrolling interests	(14)						(14)
Ending Balance at Aug. 31, 2016	$ 2,457,497	$ 250	$ 2,034,525	$ 1,660,820	$ (39,877)	$ (1,217,547)	$ 19,326
Ending Balance (in shares) at Aug. 31, 2016	186,998,472	186,998,472