Note 13 - Stockholders' Equity (Details Textual) - USD ($) $ / shares in Units, $ in Millions				3 Months Ended				9 Months Ended
	Mar. 27, 2017	Jul. 05, 2016	Jul. 01, 2016	Feb. 28, 2017	[1]	Nov. 30, 2016		May 31, 2017	May 31, 2016	Aug. 31, 2016	Aug. 31, 2015
Treasury Stock, Shares								12,539,371		11,112,753
Common Stock, Shares, Outstanding								39,198,325	40,656,000	40,038,225	41,317,000
Stock Repurchase Program, Increase in Authorized Amount	$ 300.0
Stock Repurchase Program, Remaining Authorized Repurchase Amount								$ 288.2
Treasury Stock, Value, Acquired, Cost Method								$ 208.8	$ 189.5
Treasury Stock, Shares, Acquired								1,284,822	1,220,000
Shares Paid for Tax Withholding for Share Based Compensation								37,042	19,892
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								0		0
Preferred Stock, Shares Issued								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								51,737,696		51,150,978
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period				6,000		95,000	[2]	101,234	51,762
ASR Agreement [Member]
Treasury Stock, Value, Acquired, Cost Method			$ 120.0
Percent of Common Stock to Be Repurchased at Closing Price		80.00%
Treasury Stock, Shares, Acquired		595,607				102,916		103,000

[1] Of the 6,357 restricted stock awards that vested during the second quarter of fiscal 2017, 5,150 related to awards granted on February 3, 2014. The remaining 40% of these restricted stock awards cliff vest after five years on February 3, 2019 and are amortized to expense over the vesting period using the straight-line attribution method. The other restricted stock awards that vested related to awards granted in February 2015 in connection with the Code Red acquisition, which vested 100% on February 9, 2017.

[2] Of the 94,877 restricted stock awards that vested during the first quarter of fiscal 2017, 73,522 related to awards granted on November 1, 2013. The remaining 40% of these restricted stock awards cliff vest after five years on November 1, 2018 and are amortized to expense over the vesting period using the straight-line attribution method. The other restricted stock awards that vested related primarily to awards granted in November 2015, which vest 20% per year on the anniversary date of the award.