Note 13 - Stockholders' Equity (Details Textual) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended			9 Months Ended
	May 19, 2016	May 31, 2016	Nov. 30, 2015		May 31, 2016	May 31, 2015	Aug. 31, 2015	Aug. 31, 2014
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period		15,000	37,000	[1]	51,762	68,178
Preferred Stock, Shares Issued		0	0		0		0
Preferred Stock, Shares Outstanding			0
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
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		50,907,581			50,907,581		50,328,423
Treasury Stock, Shares		10,251,413			10,251,413		9,011,521
Common Stock, Shares, Outstanding		40,656,168			40,656,168	41,531,000	41,316,902	41,793,000
Treasury Stock, Shares, Acquired					1,220,000
Treasury Stock, Value, Acquired, Cost Method					$ 189.5
Stock Repurchase Program, Additional Amount Authorized	$ 165.0
Stock Repurchase Program, Remaining Authorized Repurchase Amount		$ 359.7			$ 359.7
Shares Paid for Tax Withholding for Share Based Compensation					19,892	23,192

[1] All of the 37,079 restricted stock awards that vested during the first quarter of fiscal 2016 related to awards granted on November 8, 2010. The remaining 40% of these restricted stock awards cliff vested after five years on November 8, 2015 and were amortized to expense over the vesting period using the straight-line attribution method.