Note 14 - Stockholders' Equity (Details Textual) - USD ($) $ / shares in Units, $ in Thousands			12 Months Ended
	Jun. 24, 2019	Jan. 31, 2018	Aug. 31, 2019		Aug. 31, 2018		Aug. 31, 2017
Preferred Stock, Shares Authorized			10,000,000		10,000,000
Preferred Stock, Par or Stated Value Per Share			$ 0.01		$ 0.01
Preferred Stock, Shares Outstanding, Ending Balance			0		0
Preferred Stock, Shares Issued, Total			0		0
Common Stock, Shares Authorized			150,000,000		150,000,000
Common Stock, Par or Stated Value Per Share			$ 0.01		$ 0.01
Common Stock, Shares, Issued, Total			40,104,192		39,264,849
Treasury Stock, Shares, Retired		13,292,689
Treasury Stock, Retired, Cost Method, Amount					$ (0)
Treasury Stock, Shares, Ending Balance			1,986,352		1,072,263
Treasury Stock, Shares, Acquired			882,445		1,534,398
Treasury Stock, Value, Acquired, Cost Method			$ 213,130		$ 302,441		$ 253,131
Stock Repurchase Program, Increase in Authorized Amount	$ 210,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount			$ 238,600
Share-based Payment Arrangement, Shares Withheld for Tax Withholding Obligation			31,644		8,070		49,771
Payment, Tax Withholding, Share-based Payment Arrangement			$ 7,200		$ 1,500		$ 7,800
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period			85,401	[1]	26,599	[2]	132,000	[3]
Treasury Stock [Member]
Treasury Stock, Shares, Retired					13,292,689
Treasury Stock, Retired, Cost Method, Amount		$ (1,700,000)			$ (1,697,205)
Treasury Stock, Shares, Acquired			882,445		1,534,782		1,556,660
Treasury Stock, Value, Acquired, Cost Method			$ 213,130		$ 302,441		$ 253,131
Common Stock [Member]
Treasury Stock, Shares, Retired					13,292,689
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 85,401 restricted stock awards that vested during fiscal 2019 were comprised of: 42,276 of awards relating to restricted stock granted on November 1,2013 and 9,451 of awards relating to restricted stock granted on October 16, 2015, which vest at a rate of 20% annually upon the anniversary date of the grant, respectively, 18,691 of awards relating to restricted stock granted on February 9, 2015, which vest 100% upon the four year anniversary date of the grant, 8,924 of awards relating to restricted stock granted on June 30, 2017, which vest 60% after three years and 40% after five years. Additionally, there were 6,059 awards that vested related to other grants.

[2] The 26,599 restricted stock awards that vested during fiscal 2018 were comprised of: 9,765 of awards relating to restricted stock granted on October 16, 2015 and 8,600 of awards relating to restricted stock granted on June 30, 2017 which vest at a rate of 20% annually upon the anniversary date of the grant, respectively. Additionally, 8,234 awards vested related to other grants.

[3] 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.