Note 14 - Stockholders' Equity (Details Textual) - USD ($) $ / shares in Units, $ in Thousands			8 Months Ended		12 Months Ended
	Mar. 26, 2018	Jan. 31, 2018	Aug. 31, 2018	Aug. 31, 2017	Aug. 31, 2018	Aug. 31, 2017		Aug. 31, 2016		Aug. 30, 2018
Preferred Stock, Shares Authorized			10,000,000	10,000,000	10,000,000	10,000,000
Preferred Stock, Par or Stated Value Per Share			$ 0.01	$ 0.01	$ 0.01	$ 0.01
Preferred Stock, Shares Outstanding, Ending Balance			0	0	0	0
Preferred Stock, Shares Issued, Total			0	0	0	0
Common Stock, Shares Authorized			150,000,000	150,000,000	150,000,000	150,000,000
Common Stock, Par or Stated Value Per Share			$ 0.01	$ 0.01	$ 0.01	$ 0.01
Common Stock, Shares, Issued, Total			39,264,849	51,845,132	39,264,849	51,845,132				39,264,849
Treasury Stock, Shares, Retired		13,292,689
Treasury Stock, Retired, Cost Method, Amount		$ 1,700,000
Treasury Stock, Shares, Ending Balance			1,072,263	12,822,100	1,072,263	12,822,100
Treasury Stock, Shares, Acquired				1,554,822	1,534,398
Treasury Stock, Value, Acquired, Cost Method				$ 252,800	$ 302,441	$ 253,131		$ 352,283
Stock Repurchase Program, Increase in Authorized Amount	$ 300,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount			$ 241,700		$ 241,700
Shares Paid for Tax Withholding for Share Based Compensation			8,070	49,771	8,070	49,771		27,625
Payments Related to Tax Withholding for Share-based Compensation			$ 1,500	$ 7,800	$ 1,500	$ 7,800		$ 4,500
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period				132,194	26,599	132,000	[1]	69,000	[2]
Common Stock [Member]
Treasury Stock, Retired, Cost Method, Amount		100			$ 133
Additional Paid-in Capital [Member]
Treasury Stock, Retired, Cost Method, Amount		186,700			186,717
Retained Earnings [Member]
Treasury Stock, Retired, Cost Method, Amount		$ 1,500,000			$ 1,510,355

[1] The 132,194 restricted stock awards that vested during fiscal 2017 were comprised of: 73,522 of awards relating to restricted stock granted on November 1, 2013, which cliff vested 60% after three years, 17,328 of awards relating to restricted stock granted on October 16, 2015, which vested 20% annually upon the anniversary date of the grant and 30,162 of awards relating to restricted stock granted on October 16, 2015, which were modified to accelerate vest 100% in conjunction with employee severance. Additionally, 11,182 awards vested related to other grants.

[2] The 69,244 restricted stock awards that vested during fiscal 2016 were comprised of: 37,079 of awards relating to restricted stock granted on November 8, 2010 (remaining 40%) and 14,683 restricted stock awards that were granted on April 8, 2013, which cliff vest 20% annually upon the anniversary date of the grant. Additionally, 17,482 awards vested related to other grants.