Consolidated Statement of Changes in Stockholders' Equity (USD $) In Thousands, except Share data	Common Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]	Total
Balance at Sep. 25, 2010	$ 38,453	$ (2,854)	$ 344,976	$ 380,575
Balance (in Shares) at Sep. 25, 2010	18,491,000
Issuance of common stock upon exercise of stock options	4,608			4,608
Issuance of common stock upon exercise of stock options (in Shares)	214,000
Issuance of common stock for employee stock purchase plan	769			769
Issuance of common stock for employee stock purchase plan (in Shares)	20,000
Foreign currency translation adjustment		(1,060)		(1,060)
Issuance of common stock to directors	75			75
Issuance of common stock to directors (in Shares)	2,000
Dividends declared			(8,754)	(8,754)
Share-based compensation	1,112			1,112
Net earnings			55,063	55,063
Balance at Sep. 24, 2011	45,017	(3,914)	391,285	432,388
Balance (in Shares) at Sep. 24, 2011	18,727,000
Issuance of common stock upon exercise of stock options	3,332			3,332
Issuance of common stock upon exercise of stock options (in Shares)	105,000
Issuance of common stock for employee stock purchase plan	896			896
Issuance of common stock for employee stock purchase plan (in Shares)	20,000
Foreign currency translation adjustment		782		782
Issuance of common stock under deferred stock plan	687			687
Issuance of common stock under deferred stock plan (in Shares)	70,000
Dividends declared			(9,795)	(9,795)
Share-based compensation	1,246			1,246
Repurchase of common stock	(8,167)			(8,167)
Repurchase of common stock (in Shares)	(142,000)			(142,038)
Net earnings			54,118	54,118
Balance at Sep. 29, 2012	43,011	(3,132)	435,608	475,487
Balance (in Shares) at Sep. 29, 2012	18,780,000			18,780,000
Issuance of common stock upon exercise of stock options	2,905			2,905
Issuance of common stock upon exercise of stock options (in Shares)	80,000
Issuance of common stock for employee stock purchase plan	1,043			1,043
Issuance of common stock for employee stock purchase plan (in Shares)	20,000
Foreign currency translation adjustment		(571)		(571)
Unrealized holding loss on marketable securities		(2,227)		(2,227)
Issuance of common stock under deferred stock plan	103			103
Issuance of common stock under deferred stock plan (in Shares)	1,000
Dividends declared			(12,010)	(12,010)
Share-based compensation	1,954			1,954
Repurchase of common stock	(14,500)			(14,500)
Repurchase of common stock (in Shares)	(204,000)			(204,397)
Net earnings			64,381	64,381
Balance at Sep. 28, 2013	$ 34,516	$ (5,930)	$ 487,979	$ 516,565
Balance (in Shares) at Sep. 28, 2013	18,677,000			18,677,000