Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Common Shares [Member]	Additional Paid-In Capital (APIC) [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income [Member]	Treasury Stock [Member]
Beginning balance at Aug. 25, 2012	$ 144,691	$ 25,888	$ 28,496	$ 477,490	$ (3,686)	$ (383,497)
Beginning balance (in shares) at Aug. 25, 2012		51,776,000				(23,122,000)
Stock option exercises	$ 75		9			$ 66
Stock option exercises (in shares)	4,000					4,000
Creation/utilization of APIC pool due to stock award	$ 86		86
Issuance of restricted stock	438		(729)			$ 1,167
Issuance of restricted stock (in shares)						71,000
Vesting of directors' stock units	158		158
Stock-based compensation, net of forfeitures	1,511		1,314			$ 197
Stock-based compensation, net of forfeitures (in shares)						12,000
Payments for the purchase of common stock	(12,718)					$ (12,718)
Payments for the purchase of common stock (in shares)						(882,000)
Prior service cost and actuarial loss, net of tax	1,650				1,650
Plan amendment, net of tax	2,676				2,676
Unrealized appreciation of investments, net of tax	209				209
Net income	31,953			31,953
Ending balance at Aug. 31, 2013	170,729	$ 25,888	29,334	509,443	849	$ (394,785)
Ending balance (in shares) at Aug. 31, 2013		51,776,000				(23,917,000)
Stock option exercises	$ 2,057		771			$ 1,286
Stock option exercises (in shares)	77,833					78,000
Creation/utilization of APIC pool due to stock award	$ 441		441
Issuance of restricted stock	1,500		(779)			$ 2,279
Issuance of restricted stock (in shares)						137,000
Stock-based compensation, net of forfeitures	1,965		1,905			$ 60
Stock-based compensation, net of forfeitures (in shares)						3,000
Payments for the purchase of common stock	(26,340)					$ (26,340)
Payments for the purchase of common stock (in shares)						(1,028,000)
Prior service cost and actuarial loss, net of tax	(5,024)				(5,024)
Plan amendment, net of tax	2,216				2,216
Unrealized appreciation of investments, net of tax	151				151
Net income	45,053			45,053
Ending balance at Aug. 30, 2014	$ 192,748	$ 25,888	31,672	554,496	(1,808)	$ (417,500)
Ending balance (in shares) at Aug. 30, 2014		51,776,000				(24,727,000)
Stock option exercises (in shares)	0
Creation/utilization of APIC pool due to stock award	$ 124		124
Issuance of restricted stock	1,410		(1,950)			$ 3,360
Issuance of restricted stock (in shares)						199,000
Stock-based compensation, net of forfeitures	2,221		2,172			$ 49
Stock-based compensation, net of forfeitures (in shares)						3,000
Payments for the purchase of common stock	(6,519)					$ (6,519)
Cash dividends paid and accrued on common stock	(9,765)			(9,765)
Payments for the purchase of common stock (in shares)						(300,000)
Prior service cost and actuarial loss, net of tax	(2,917)				(2,917)
Plan amendment, net of tax	2,451				2,451
Net income	41,210			41,210
Ending balance at Aug. 29, 2015	$ 220,963	$ 25,888	$ 32,018	$ 585,941	$ (2,274)	$ (420,610)
Ending balance (in shares) at Aug. 29, 2015		51,776,000				(24,825,000)